1

GOMPER SUNDAY

PG/M.Ed/09/50562

THE EFFECT OFNEEM ON THE WOOD PRESERVATION IN PLATEAU STATE

FACULTY OF EDUCATION

DEPARTMENT OF VOCATIONAL TEACHER EDUCATION

Chukwuma Ugwuoke

Digitally Signed by: Content manager’s Name

DN : CN = Webmaster’s name

O= University of Nigeria, Nsukka

OU = Innovation Centre

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THE EFFECT OF NEEM OIL ON WOOD PRESERVATION IN

PLATEAU STATE

BY

GOMPER, SUNDAY

PG/M.ED/09/50562

DEPARTMENT OF VOCATIONAL TEACHER EDUCATION,

(INDUSTRIAL TECHNICAL EDUCATION)

UNIVERSITY OF NIGERIA, NSUKKA

MARCH, 2013

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CHAPTER 1

INTRODUCTION

Background of the Study

Wood is an organic material with a hard fibrous tissue found in trees and many plants. It

is made up of compounds mainly of cellulose fibre having long, straight and strong

glucose molecules forming the skeleton of the plant wall (Porter & Rose, 2007).

According to Hodgson, Bear and Deer (2009), wood is made up of cellulose (up to 45%),

hemi cellulose (20-30%), lignin (25-30) and other substances. The main structural

component of wood cell is the cellulose which is the most common naturally occurring

composite on earth consisting of a linear chain of several hundreds to over ten thousand

linked D-glucose units (Klemn, Philip, Heanze & Wagenknecht, 1998). Wood is

classified into two distinct kinds known as hardwood and softwood which are derived

from deciduous and coniferous trees respectively. According to Woodford (2011), the

classification of wood as hardwood or softwood for use however is based on their biology

and anatomy hence some hardwoods are softer than some softwoods and vice versa which

have implications for how and where they are used.

Throughout history, people have relied on wood for needs varying from housing,

furniture, tools, transport, entertainment, learning, certification and multitude of other

products. According to Fuwape (2000), wood from time immemorial has been established

as a construction material in wood industries for variety of applications such as

construction of buildings, furniture items, bridges, boats, ships, lorries, tractor wagons and

aircraft carrier. Bamiro, Nurudeen and Akunu (1986) captured the use of wood to include

the production of musical components such as guitar, piano, violin, tambourines; in tool

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making such as hammer handles, pick axes, pulp and paper for the production of exercise

books, newspapers, magazines; sports wares such as hockey sticks, tennis bats, tennis

rackets and cricket bails are also made from wood.

The wide range use of wood, technological advancement, wood deterioration,

deforestation and population increase in Nigeria have placed a remarkable rise in demand

and use of timber. Okafor (1982); Sekumade and Oluwatayo (2011) observed that the

demand for timber is rising in every part of the country without a balanced supply to meet

this demand. Akpan, Apagu and Olufemi (2001) had asserted also that timber is gradually

becoming scarce and expensive particularly in Northern Nigeria and therefore

recommended the need to find alternative timber species to supplement the existing

economic species commonly in use which include Obeche, Mahogany, Iroko, Afara,

Sapele, Mansonia, Agba and several others. The wood industries in Plateau State have

quickly responded to this search for alternative timbers by exploring the use of lesser

known timbers such as Canarium Schweinfurthii(Atile), Ceiba Pentandra(Rimi),

Isoberlina Doka(Doka) and Daniellia Oliveri(Achuwale-Maje) for various constructions

except for the susceptibility of some of these timbers to wood deterioration(Keay,1989).

Fuwape(2000), however recommended the growing of these timbers in plantations to help

solve the problem of timber scarcity in the country and by extension, the northern part in

particular.

As important as timber is to the wood industries and the end users, there is

however the threat of wood degradation brought about by mechanical wear through

abrasive action, decomposition caused by physical agencies such as prolonged heating or

exposure to weather and chemical decomposition (Porter & Rose, 2007; Goodell,

Nicholas & Schultz, 2003). Another common major cause of wood degradation is bio-

deterioration which is the action of foreign biological agencies such as fungi, insects,

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bacteria and marine borers. According to Wong and Cheok (2001), wood degradation by

termites is a chronic problem in many tropical and even some temperate regions of the

world, resulting in serious monetary, material losses and an increasing demand for timber.

Wong and Cheok (2001) seem to concur with Ezeji‟s (1984) earlier position when he

reported that major destructive agents to buildings constructed of sound materials and

workmanship are the termites.

Termites are a type of insect pests which are classified as social because of their

characteristics to stay in groups. They mostly feed on dead plant material, mostly wood,

leaf litter, soil, or animal dung. According to Ezeji (1984), termites are insects which live

in communities and feed principally on wood substance called cellulose. The cellulose is

the structural framework of the primary cell wall of wood which forms 45% to 50% of the

wood substance. The major types of termites that attack and feed on wood‟s cellulose are

identified as the subterranean, damp wood and the dry wood termites (Ezeji, 1984;

Lebow, 2006; Jones, Kick-Raack & Pound, 2007).

Subterranean termites are ground-dwelling social insects living in colonies and

these termites have the ability to adjust the depth of their colony in soil depending on

temperature and moisture requirements (Jones, Kick-Raack & Pound, 2007; Lee, Wu &

Smith, 2003). These termites reach wood or cellulose materials above ground by

constructing and travelling through earthen (mud) tubes. The mature colony consists of

three castes; reproductives (king and queen), soldiers and workers. It takes about 4 to 5

years for a colony to reach its maximum size and it may consist of 60,000 to 200,000

workers who are in charge of destroying wood in search of food for their colony (Kamble,

1991).

Unlike subterranean termites, Dry-wood termites are very secretive insects and are

difficult to detect. They live deep inside wood and do not require any contact with the

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soil, except during periods when they swarm or when repair work is being done on

infested homes , they are seldom seen (University of California; 1996, Arango & Green,

2006). According to Ezeji (1984), these termites make narrow holes by eating out the

timber and that the galleries so made provide accommodation for the various members of

the colony. As the number of galleries increases, they merge to form large cavities in the

timber and the evidence of their infestations can hardly be noticed until they eat up the

wood leaving the casing.

Mathias and Lorella (2006) and the pest management bulletin of Whitmire Micro-

GenTermite(2008)however highlighted some of the evidences of wood infestation by the

various termites to include weight loss, loss of form and shape, wood easily breaks apart,

development of shelter tubes, galleries or tunnels in an irregular pattern, dull sound when

tapped and structural weakness. In Nigeria, the subterranean and dry-wood termites have

been identified as major cause of wood biodegradation (Femi-Ola & Aderibigbe, 2008;

Ezeji, 1984).Wood degradation by termites and other insects over the years according to

Matias and Lorella(2006) have been inhibited by using naturally resistant wood species

and the use of wood preservatives.

Wood preservatives are chemicals that are applied on wood in order to prolong its

service life. Thomasson, Capizzi, Dost, Morrell and Miller (1998) defined wood

preservative as any substance that for a reasonable length of time is effective in

preventing the development and action of wood fungi, termites and pests of various kinds.

Wood preservatives must meet two broad criteria; they must provide the desired wood

protection in the intended end use and must do so without presenting unreasonable risks to

people or the environment. Bamiro, Nurudeen and Akunu (1986), Lebow (2006) and

Kingsland (2011) enumerated the qualities of a good wood preservative to be: poisonous

to the destructive agents but harmless to its operators, easy to handle and apply to wood,

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odourless, cheap and easily obtainable, Chemically stable for a long period, leach and

evaporation proof.

Wood preservatives are classified into three general classes which are the Oil-type

or Oil borne preservatives, such as Creosote, Coal- Tar, Solignum and petroleum

solutions of pentachlorophenol; Water borne preservatives such as Chromated Copper

Arsenate, Ammoniacal Copper Zinc Arsenate and boron; and the Organic-Solvent

preservatives such as Chlorinated phenols and Sodium Pentachlorophenol (Porter & Rose,

2007; Lebow, 2006). These wood preservatives are applied on wood for either interior or

exterior wood constructions. The common methods of applying the wood preservatives

are brushing and spraying, dipping and soaking, hot and cold tank; and pressure treatment.

According to Thomasson, Capizzi, Dost, Morell and Miller (1998), preservatives are

applied on the basis of how and where the products will be used, the expected conditions

of exposure to wood destroying agents in the ground, above the ground and in marine

environment. The length of time over which these chemicals remain effective as stated by

Ezeji (1984), depends on a number of factors including the type of soil, exposure to

weather and the kind of termite involved.

The effectiveness of wood preservative against termites according to Edlund,

Evans and Henriksen (2006) is established when the preservative treated wood has high

resistance to termites infestation in situations close to the practical usage over a period

without losing its efficacy of protecting the wood. The question of effectiveness of the

highly toxic chemical preservatives to inhibit and destroy wood deteriorating agents and

in particular termites is not in doubt but the hazards associated with their use have led to

their ban in the United States of America and the 27 European Union countries(European

Union Commission, 2001; Dickey, 2003).

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The ban on the use of creosote, coal-tar, solignum, chromate copper arsenate,

ammonical copper arsenate, pentachlorophenol and several others due to the high level of

toxicity to the handlers of wood preservatives, residential and non-residential users of

treated wood and the environment, has opened up alternative development of low and non

toxic wood preservatives in the EU countries and the US. Some of these new wood

preservatives such as alkaline copper quaternary, concentrated borate, copper azole,

biguanide, and polyionenes are available only in the EU countries but very expensive and

are yet to reach non EU countries (Su, Zhang, Xie, Chen & He, 2002; Matias & Lorella.,

2006, EU Commission, 2001). There is therefore need for the developing countries to

look for alternative wood pest control preservatives that are low in toxic content or non

toxic to human beings and the environment. The possibility of getting an effective,

environmentally and humanly safe wood preservative may be found in organically based

sources such as plants and tree extracts; a likely source might be extracts from the neem

tree.

The neem tree (Azadirachta Indica A. Juss) is a tropical evergreen with wide

adaptability and like the Mahogany tree is known to be resistant to insect infestation

according to Giger (2001). The tree is native to India and Burma but transplanted to

Africa. Neem is one of the most versatile, multifarious trees of tropics, with immense

potentials as postulated by Girish and Shankara, (2008); they noted that neem tree

possesses maximum useful non-wood products (leaves, bark, flowers, fruits, seeds, gum,

oil and neem cake) than any other tree species. These non-wood products are known to

have anti-allergenic, anti-dermatic, anti-feeding, anti-fungal, anti-inflammatory, anti-

pyorrhoeic, anti-scabic, cardiac, diuretic, insecticidal, larvicidal, nematicidal, spermicidal

and other biological activities; because of these enormous applications, neem has become

a green treasure tree in many countries ( Giger, 2001; Girish & Shankara, 2008).

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In Nigeria, neem tree commonly known as Dogonyaro is now widely grown and

thrives well in the northern part of Nigeria. In Plateau State, there is high density of the

tree especially in the southern part of the State and the seeds are easy to collect from the

ground or could be harvested (Keay, 1989; Akpan, Apagu and Olufemi, 2001). Neem oil

is extracted from the seeds of neem tree which contain 45% of brown and bitter oil

(Hayden, 1998; Giger, 2001). The wide applications of neem extracts provided a window

for its oil to be examined if it can be used for wood preservation of predominant timbers

in Plateau State.

Statement of the Problem

The rising demand of timber in Nigeria and in Plateau State in particular has

forced the wood industries to resort to the use of lesser known and predominant timbers

available in the locality. Timbers such as Canarium Schweinfurthii (Atile), Ceiba

Pentandara (Rimi), Isoberlina Doka(Doka) and Daniellia Oliveri (Achuwale-Maje) are

used for various wood constructions(Keay, 1989). Some of these timbers however are

susceptible to termite infestation which leads to much damage to the structure of wood

with the effect of material, monetary and loss of lives. Termites especially the

Subterranean and damp-wood types are the most destructive and prevalent in the tropical

countries and in Nigeria in particular and if wood must continue to meet varied needs,

protection from termites during processing, merchandising and use must be provided

(Nair, 2006; Ezeji, 1984).

Termite infestation of wood can be halted with the conventional chemical

preservatives which have been in use for about two centuries ago. Some of the commonly

used preservatives such as creosote, coal-tar, solignum, chromate copper arsenate,

ammonical copper arsenate, pentachlorophenol and several others have been discovered

to be unsafe for humans and the environment because of their carcinogenic toxins which

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affect the skins and the lungs through contact and inhalation of the fumes respectively

(Su, Zhang, Xie, Chen & He, 2002; Matias & Lorella, 2006; EU Commission, 2001).

Also affected by the chemical preservatives is the environment within which they are used

because plant and aquatic lives are destroyed through leaching of the chemicals in the

waterways (Matias & Lorella, 2006; EU Commission, 2001).

In view of the major draw backs of the chemical preservatives, the European

Union countries and the United States had banned the use of these chemicals for wood

preservation in their countries. They had however developed alternative safe preservatives

which are expensive and unavailable to developing countries like Nigeria (Cowie, Logan

& Wood, 2009; EU Commission, 2001; UNEP, 2000).

The disturbing trend however is that these banned preservatives are still being sold and

used by the wood industries in Nigeria and by extension Plateau State (EU Commission,

2001; Dickey,2003; UNEP, 2000). There was therefore a need to search for alternative

wood preservatives that are very low in toxic content or non- toxic to humans and the

environment but effective to protect and ensure long service years of the predominant

timbers being used in Plateau State.

Purpose of the Study

The main purpose of the study was to determine the effect of neem oil as a

preservative for wood in Plateau State.

Specifically, the study was to determine:

1. The weight loss of termite infested untreated wood.

2. The effect of neem oil on the weight loss of termite infested treated wood.

3. The extent of deterioration of termite infested untreated wood.

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4. The effect of neem oil on the extent of deterioration of termite infested treated

wood.

5. The extent of termite infestation of untreated wood in exterior and interior

environments.

6. The effect of neem oil on the extent of termite infestation of treated wood in

exterior and interior environments.

Significance of the Study

The study will be of benefit to many individuals and groups, including woodwork

and building technology teachers and students, Industrialists and Entrepreneurs, the

Society, Environmental Protection Agency, Professional bodies, Government Policy

Makers, Research Institutes and the Wood industries.

The Woodwork and Building Technology Teachers will find neem oil as an

alternative preservative for application on various wood items and projects produced in

the school workshop and a new frontier of knowledge to enrich their teaching on wood

preservatives for the students. The students will also benefit from the use of neem oil as a

preservative on their various wood and building course practical projects.This is because

neem oil as an alternative preservative would be produced by wood finishing industries in

large quantity and will be readily available in the school shops for use.

The findings of the study will help Industrialists and Entrepreneurs to have a new

area of investment in the production and marketing of neem oil with the assurance of a

sustainable renewable source of raw material as there will be increase in the planting of

neem trees on account of the awareness of the potentials of neem oil. This circle is

capable of stimulating industrial growth in the processing of neem oil.

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The Society will find the study useful in exploring the economic benefit of raising

more neem trees and new market for the seeds and the oil having established the non toxic

nature of neem oil and as a substitute for the chemical preservative. The demand for neem

oil will also increase hence the motivation to raise more trees. The environmental safety

of the habitat as a result of using neem oil will also motivate the society to massively

plant neem trees as the health of the people will be secured.

The findings of the study will be beneficial to the Environmental Protection Agency in

their advocacy for a safer and healthier environment. It will make the enforcement of

environmental laws easier because of available substitute for the preservatives that

endanger lives and pollute the environment.

Woodwork and Building Technology professionals will benefit from the findings

of the study in enriching the list of recommended safe preservatives in their professional

brochures, in setting standards for the production and use of neem oil so that the efficacy

of its protection would not be compromised. The finding that neem oil is a substantiated

preservative, is capable of boosting the image of the professional body in public domain

as a body that is practically oriented than arm chair theorists.

Individual house builders, owners and those with intention to build will use

findings of the study in treating structural wood for their constructions with neem oil

having established that neem oil is non toxic, effective and can be used as a substitute for

the toxic preservatives that hitherto have been used to achieve protection for the wood,

environment and secure the health of the people.

The Wood Industries will use the findings of the study in obtaining neem oil as a

safer alternative preservative for protecting wood in building construction, furniture and

carpentry work, joinery, for interior and exterior protection of wood items and

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structures.For instance, that neem oil is found to provide high reduction in deterioration

levels due to termite infestation, the demand for it as an alternative preservative soars in

the local Nigerian markets. The cost of production will also be reduced as wood industries

may not rely on imported chemical preservatives for treating the wood that is used.

Government policy makers both at State and Federal levels will benefit from

findings of the study in enacting policies that support the massive raising of neem trees

and related processing industries having established the fact that neem oil has the capacity

to provide equally effective protection for wood, it is safe for the environment and can

serve as means of reducing poverty and unemployment levels in the country. Policies to

stop or regulate the importation of chemical preservatives can be developed thereby

saving foreign earnings for the country. The programmes of government in checking the

advancement of desert lands in the savannah regions will receive a boost with more neem

trees planted which also has implication for the climate change advocacy in the country.

Research Questions

1. What was the weight loss of termite infested untreated wood?

2. What was the effect of neem oil on the weight loss of termite infested treated

wood?

3. What was the extent of deterioration of termite infested untreated wood?

4. What was the effect of neem oil on the extent of deterioration of termite infested

treated wood?

5. What was the extent of termite infestation of untreated wood in exterior and

interior environments?

6. What was the effect of neem oil on the extent of termite infestation of treated

wood in exterior and interior environments?

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Delimitation of the Study

The study was delimited to wood weight loss, deterioration of timber, infestation

of termites on wood treated with neem oil exposed to interior and exterior environments.

It was also delimited to the following predominant timbers in Plateau-State: Canarium

Schweinfurthii (Atile), Ceiba Pentandra (Rimi), Isoberlina Doka(Doka) and Daniellia

Oliveri (Achuwale-Maje).

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CHAPTER II

REVIEW OF RELATED LITERATURE

The related literature for the study was reviewed under the following sub-

headings:

Conceptual Framework

Wood as a Material for Building Construction

Wood and Weight Loss

Main Trees for Building Construction in Nigeria

Predominant Hardwoods and Softwoods of Plateau State

Wood Deterioration

Termites and Termites Infestations of Wood

Wood Preservation in Nigeria and Plateau State

Toxic Preservatives and Treatment Methods

Alternative Non-Toxic Preservatives

Neem Tree and its Oil

Theoretical Framework

Theory of Wood Preservation

Theory of Penetration/ Retention of Preservatives

Theory of Osmotic Pressure Treatment

Review of Related Empirical Studies.

Summary of Review of Related Literature.

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NEEM

Oil

But

Neem

Oil

FIG. 1: Schema of Conceptual Framework for the Study on the Effect of Neem Oil as Wood Preservative in Plateau State (Designed by the researcher, 2012)

If Neem oil is not

effective in

preserving

alternative timbers

Transportation

Furniture

Building construction

Others

Entertainment

Sports equipment

Education materials

Demand for

timber

increased for

both durable

and non -

durable

timbers

Scarcity of

durable

Timbers e.g.

Iroko, Afara,

Mahogany,

Mansonia,,,

Search for

Alternative

Timbers

Neem oil if proven to

be effective

alternative wood

preservative for

predominant timbers Search for locally

available non -

toxic preservative

for use in Nigeria

and Plateau state

in particular

Alternative

preservatives available

in EU countries and

U.S.A, but unavailable

and too expensive for

developing countries

like Nigeria

Global Search for

alternative low

toxic and non-toxic

preservatives

Use of chemical

preservatives is

toxic to human and

the environment

Uses of Wood

Wood deterioration by

termites a challenge to

the use of alternative

Timbers

Use of Chemical

Preservatives on the

alternative timbers

To meet these uses

Alternative

Timbers

have been

found e.g.

Atile, Rimi,

Doka, Maje But

Neem Oil

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1. Conceptual Framework

Wood is the most common construction material used in carpentry, creating the

simplest to the most luxurious homes, sturdy furniture and smoothest papers used in

Education. Technology has opened countless new uses for wood and its by-products that, until

recently were never considered. The diverse use of wood however has created an insatiable

demand for wood in Nigeria and in particular Plateau State where the demand for wood has

forced the wood industry to seek for alternative local timbers to meet up with this demand

(Fuwape, 2000). A major challenge however for the predominant timbers for wood

construction in Plateau State like any other place in Nigeria and overseas is the destructive

activities of termites in addition to other pests, fungi and bacteria that damage wood and

reduce its service year (Nair, 2006). The extent of damage by termites is more noticeable on

susceptible softwood and hardwood but the use however of chemical preservatives on wood

would halt these attacks. According to Matias and Lorella (2006) however, some of the most

common of these chemicals in use are found to be very toxic to handlers, end users of wood

items and the environment; hence the need to look for non toxic and low toxic preservatives

as alternatives.

Alternative low and non toxic chemical preservatives have been developed in the EU

countries and the US but are found to be expensive even within the countries of use hence

unavailable to developing countries including Nigeria (EU Commission, 2001). A need

therefore to develop locally available low and non toxic preservatives that are equally

effective is pertinent to halt the infestation of termites of wood that are sourced from

predominant trees in Plateau State. In Plateau State, one of the trees with enormous

potentials of being a source of non-toxic or low toxicity wood preservative is the neem tree

and its extracts; one of the extracts of the neem tree is the seed from which oil could be

extracted. This study seeks to explore the use of neem oil as an alternative wood preservative

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for predominant timbers in Plateau State thereby increasing their service years and the variety

of timbers that can be used for various construction and aesthetic purposes.

Wood as a Material for Building Construction

Wood over the ages has always been a primary housing construction material. Once

man left the natural shelter of caves and began to build his own shelter where he wanted it, the

most universally available material was, usually, wood. Freas (2011) explained the use of

wood as a structure to include interior and exterior cladding, in laminates, in carpentry, in

ceilings, in walls and roofs, for floors, and several others. In Nigeria, the major area of

structural utilization of wood is in roof construction, the building industry alone consuming

about 80% of the country‟s estimated 20 million cubic meters of annual timber production

(Lucas, Olurunnisola and Adewole, 2006). According to a UNESCO-NIGERIA Technical

and Vocational Education Revitalization Project (2008), Wood is valuable as a building

material for a number of reasons. It is structurally useful because of its high strength in

relation to its density. It is comparatively easy to work to a variety of shapes either by hand or

by machine, is durable under appropriate conditions, and can give a good finished appearance

at reasonable total cost. Other advantages of using wood as a building material according to

Freas(2011) and Ezeji(1984) include low cost due to its light weight, durability if treated well

with preservatives, a non-conductor of heat and low energy consumption required to produce,

ease of transport and processing; it is an inexhaustible natural resource which depends on

infinite solar energy for its growth and production. The nature of wood use has, of course,

varied from region to region and changed with time. Log structures have been common in

many areas; and sapling-size supports for coverings of hide, cloth or leaves have been used by

many different cultures, particularly nomads, because of easy transportability and as man has

developed, so has his use of wood for shelter. Modern man in some areas still uses a great

deal of wood in housing, but he now has it available in a variety of forms which have resulted

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from technological advances. He has a considerable scientific background which permits

greater structural efficiency, and more effective protection from heat and cold; and from

destructive element such as fire, fungi, insects and weather which pose as problems of using

wood for building construction in Nigeria. Anaele (2010) recommends that appropriate

technology should be developed that will make use of locally available building material

resources and improve upon local procedures to reduce problems associated with inadequate

and costly building materials for construction in Nigeria.

Wood and Weight Loss

Wood is a natural and organic material, a hard fibrous tissue found in trees and many

plants. It is made up of organic compounds mainly composite of cellulose fibre having long,

straight and strong glucose molecules forming the skeleton of the plant wall (Porter and Rose,

2007). A study conducted by the University of Northern Iowa (2011) showed that though

cellulose is the main food for the termites, they find it difficult to digest it because of its

durable compound. The termites ingest cellulose when they feed on wood and while not many

organisms in the world can produce enzymes capable of breaking down cellulose, the

protozoa organisms within the termites digestive system do have the enzymes necessary to

break down cellulose.

The breaking down of the cellulose into digestible by-products enables the termites to

live off on the wood without actually digesting it themselves. Collaborating the findings of

the University of Iowa, Wong (2007) reports that when termites attack a piece of wood, they

are merely having a meal and that this feeding pattern reduces the wood cellulose with several

consequences for structural timber amongst which is the weight loss of the wood. Weight loss

of wood could be as a result of seasoning converted timber in which there is deliberate

attempt to reduce the moisture content in wood to enable the use of wood in a dry state and

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also prevent the attack of biodegradable organisms. The loss of weight in wood can also occur

in order to maintain the equilibrium moisture content, a situation where wood in construction

absorbs and loses moisture according to the level of humidity in the atmosphere (Porter and

Rose, 2007). Also, the attack of untreated wood by fungi, marine borers, bacteria and termites

leads to decay, loss of form and mass of wood; this is another major reason for weight loss in

wood.

Weight loss in wood for interior conditions according to Lee, Wu and Smith (2003);

Adetogun, Adegeye and Omole (2009) is determined by the formulae:

Weight loss (%) = [(W1-W2)/W1] × 100

Where, weight loss is expressed as percentage of the original dry weight,

W1 = sample weight prior to the termite test (gram); and W2 = sample weight

after the termite test (gram).

For the determination of weight loss of wood samples buried in the ground of a termite

mount, according to Ahmed, Ejaz, Riaz and Husain(2008), a correction factor has to be

calculated using the following procedures:

Derived formula for calculating C.F. is;

Weight of Wood Sample before burring = (W1) = 144g

Weight of Wood Sample after period of infestation = (W2) = 160g

Difference in weight = W2-W1=160-144=16g

So, 144g of wood gain the weight = 16g

C.F. =16/144= 0.112

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Example:-If weight of susceptible wood sample before a field test is 142g and after the

field test is 139g, then 139 is multiplied by 0.112 and the answer is subtracted from 139

because in 139 weight loss and gain are both included. Since we have to evaluate only weight

loss, then we have to subtract the weight gain due to soil moisture hence weight loss due to

termite attack is obtained, therefore:

139× 0.112 = 15.568g (weight due to soil moisture)

139-15.568= 123.432g (moisture free weight)

142g-123.432= 18.568g (weight loss due to termite infestation)

Percentage weight loss therefore is:

18.568/142×100= 13.07= 13% weight loss.

Main Trees of Building Construction in Nigeria

Every country and region of this world has its peculiar distribution of trees and

vegetation from which wood is processed for the different components of building

construction; in Nigeria, this is not different. The main trees for building construction in

Nigeria follow geographical patterns as obtainable in other Countries. Nigeria, a country

located slightly above the equatorial axis within the tropics is exposed to peculiar climate of

rainy, dry and harmattan seasons with varying intensities across various regions in the

country; based on its location, there is a vast distribution of trees and vegetation (Fuwape

,2000; Keay, 1989).

While the common trees vegetation in Nigeria might not include the distinctive South

Africa‟s baobab, Algeria and North Africa‟s pines and cedars nor Kenya‟s euphorbia and

acacia, distribution of trees for building construction in Nigeria differ between the usually dry

22

north and the mostly rainy south with the middle belt where Plateau State is located serving as

the transition zone (Community Portal of Nigeria, 2011).

The tree distributions in Southern part of Nigeria according to Okafor (1982), are

mainly those expected of a tropical rain forest region of West Africa and trees like mahogany,

iroko afara, agba, obeche and mansonia, abura, sapele and opepe define this region. Some

fruit plants like orange, mango and economic trees like rubber and palm trees (the most

abundant) are not left out while the mangrove swamp lines the creeks and the southern margin

to the atlantic. The vegetation thins down towards the north as it gradually makes a transition

from rain forest to Sahel savannah and to the fringes of Sahara desert, the tree distribution in

the northern Nigeria is in contrast to that of the South (Keay, 1989).

The main trees in the north comprise moderately sized neem, cottonwool (Rimi),

baobab, atile, doka, maje, dorowa, date palms, shrubs and plants in the extreme north . It

thus follows that the further one goes towards the north, the sparser the vegetation therefore,

the tallest and biggest trees for building construction are found in Southern Nigeria while the

north supports shrubs and moderately sized trees which are used for the same purpose.

Appendix A shows some Nigerian timber species that are commonly used for various

components in the building construction industry in Nigeria.

Predominant Hardwoods and Softwoods of Plateau State

The trees and timbers of Plateau- State are of the Guinea Savannah type comprising both of

hardwoods and softwoods. The mountain vegetation however of the isolated high mountains

and plateaus of the central and eastern part of Nigeria is not well developed because of the

great influence and interference by man and animals (Community Portal of Nigeria, 2011).

For instance, the Jos-Plateau, which is one of the highest points in Nigeria, is in a grassland

zone, but its vegetation depicts grassland at the top and base of the plateau while the slopes

23

favourably moisture laden wind, are covered by scattered forests and trees. The typical trees

of Plateau are the mango, guava, shea butter, atile, dorowa, rimi, boabab, doka, maje, acacia,

eucalyptus, neem and several other scanty species. Majority of these trees are deciduous but

are softwood and susceptible to termite infestations (Keay, 1989; Community Portal of

Nigeria, 2011). Some of the predominant timbers that are commonly used as wood for various

constructions that may require some form of protection from termite infestations are:

Atile(Canarium Schweinfurthii), Rimi(Ceiba Pentandra), Doka( Isoberlina Doka) and Maje(

Daniellia Oliveri). Appendix B shows high level of termite infestation of Rimi (Ceiba

Petandra) wood /zinc garage doors in Vom , Jos South LGA Plateau State.

Atile (Canarium Schweinfurthii)

Canarium schweinfurthii also known as Atile in vernacular language on the Plateau is a large

Agro- forest tree with its crown reaching to the upper canopy of the forest with a long,

smooth, straight and cylindrical trunk exceeding 50m, while the diameter above the heavy

root swellings can be up to4.5m. According to Keay (1989) and The Wood Explorer

Database (2011), Canarium Schweinfurthii is distributed throughout tropical Africa in the rain

forest and transitional forest from Senegal to Cameroon, Nigeria and extending to Ethiopia,

Tanzania, Angola and several other African countries where it is used for diverse functional

purposes.

Some of the functional uses of C.Schweinfurthii range from food to construction of

shelters and their furnishings. The converted timber as reported in the bulletin of

Woodworkers Source (2008) is used as a substitute for true mahogany, seasons slowly but

fairly well, works easily, stains and polishes well and that the timber is used as core veneer,

for decorative paneling, parquetry, furniture and flooring; locally, the wood is used for

mortars, planks, and canoes. Other uses include Joinery, Furniture components, Parquet

24

flooring, Plywood, Boxes and crates, Bent Parts, Cabinetmaking, Casks, Chairs, Chests,

Decorative plywood, Desks, Dining-room furniture, Drawer sides, Figured veneer, Fine

furniture, Flooring, Furniture , Furniture squares or stock, Hat racks, Kitchen cabinets,

Living-room suites, Office furniture, Packing cases, Radio, stereo, TV cabinets, Stools,

Structural plywood, Utility furniture, Utility plywood, Veneer and Wardrobes.

Canarium Schweinfurthii according to Scheffer and Morrell (1998) is very susceptible to

attack by termite and that the sapwood is readily attacked by powder-post beetles. The

heartwood of the timber is rated as extremely resistant to impregnation, but the sapwood

responds well to treatment.

Rimi(Ceiba Pentandra)

Ceiba Pentandra trees known as Rimi in Northern Nigeria belong to the family of Malvaceae

Species which includes the “baobab” trees of Africa. The trees are typically emergent

meaning that their large umbrella-shaped canopies emerge above the forest canopy (Keay,

1989). They are thus among the tallest trees in the tropical forest reaching as high as 60 m in

rainforests of the Amazon but in the savannah region of Northern Nigeria and in Plateau

State, they are scattered in farmlands(National Biodiversity Report, 2001). Their thick

columnar trunks often have large buttresses, young trunks and branches are armed with thick

conical spines, and are often green due to photosynthetic pigments. The trees lose their leaves

in the dry season, a conditioned termed "drought-deciduousness" but many are adapted to dry

conditions and are able to store water in the cortical cells of their trunk, at times this gives the

trunk a swollen or bulging appearance (Community Portal of Nigeria, 2002).

The tree‟s large and cylindrical trunk according to Keay(1989) has made the

indigenous people to prize the Ceiba for constructing enormous dugout canoes and the

construction process normally takes months to complete. Other uses of Ceiba both for interior

and external wood constructions include the production of block boards, boxes and crates,

25

decorative plywood, furniture components, insulating boards, moldings, paneling , rafts,

veneer, boat building, building materials, cabinetmaking, casks, Chairs, Chests, core stock,

desks, dining-room furniture, drawer sides, figured veneer, fine furniture, hat racks, interior

construction, interior trim, kitchen cabinets, Living-room suites(upholstery), office furniture,

Packing cases, plain veneer, plywood, radio, stereo, TV cabinets, Raft floats, Rustic furniture,

Stools, Wardrobes. The timber with such diverse areas of use however is prone to insect

attack particularly termites and decay, and liable to blue-stain unless converted rapidly after

felling (Community Portal of Nigeria, 2002; Woodworkers Source, 2008).

Doka( Isoberlinia Doka)

Isoberlinia Doka is a woodland tree which is common and widespread in west and central

Africa, where it often dominates the landscape in uncultivated areas of Guinea savannah

where Jos-Plateau is located. According to Keay(1989) and the bulletin of the Woodworkers

Source( 2008), this hardwood tree is quick to colonise clearings and abandoned land, and

grows gregariously, often establishing near-pure stands for varied uses.

Some of the uses of Isoberlinia Doka for both interior and external applications as listed by

Woodworkers Source (2008) and Keay(1989) include Boxes and crates, Core Stock,

Domestic flooring, Furniture , Joinery, Light construction, Marine construction, Pulpwood,

Railroad ties, Shipbuilding, Balusters, Barge fenders, Building construction, Building

materials, Casks, Chairs, Chests, Concealed parts (Furniture), Construction, Crossties, Desks,

Dining-room furniture, Docks, Dock-work, Dowell pins, Dowels, Drawer sides, Fine

furniture, Floor lamps, Flooring, Furniture components, Furniture squares or stock, Harbour-

work, Interior construction, Kitchen cabinets, Living-room suites, Moldings, Naval

architecture, Office furniture, Packing cases, Parquet flooring, Pulp/Paper products, Radio,

stereo, TV cabinets, Rafts, Stair-works, Stools, Stringers, Sub-flooring, Tables , Utility

furniture, Veneer, Wardrobes, Wharf construction. Scheffer and Morell (1998) and the Wood

26

Explorer Database (2011) noted that I. Doka even though a hardwood but it is susceptible to

termites, marine borer, powder-post beetles and pinhole borer attack. The heartwood of the

timber is resistant to impregnation of preservatives but the sapwood is treatable.

Maje /Achuwale(Daniellia Oliveri)

Daniellia Oliveri is commonly known as maje in vernacular in the northern part of Nigeria. It

is also referred to as the African copaiba balsam or Ilorin balsam. It belongs to the family

fabacae trees and is important both as timber and forest enrichment tree growing to a height of

between 30m to 45m with a trunk diameter of between 100cm and150cm. Daniellia Oliveri

according to Woodworkers Source (2008) and Olorunmaiye, Olorunmaiye and Fatoba(2009)

is vital in agro forestry systems, soil and water conservation; it belongs to fire resistance

savanna species. The distribution of the tree according to Keay(1989) shows that it grows in

the moisture savannah forests from Senegal to Sudan, Uganda, Zaire, and Nigeria. In Nigeria,

the tree is especially abundant in the moist savannah regions and southern part of Plateau

State in particular where the timber has been used for diverse purposes.

The wide range uses of D. Oliveri for interior and external constructions are found in

balusters, building construction, core stock, decorative plywood, decorative veneer, domestic

flooring, factory flooring, figured veneer, flooring, interior construction, interior trim, joinery,

light construction, millwork, moldings, parquet flooring, particleboard, plain veneer,

plywood, stair-works, stringers, structural plywood, sub-flooring, trimming, turnery, utility

plywood, and veneer production. D. Oliveri is a dense but perishable timber and prone to

termite attack if not treated with preservatives according to a report of a research conducted

by forest products research laboratory (http://www.nzdl.org, 2011) and this report was

supported by the Wood Explorer Database (2011) when it asserted that D. Oliveri is

susceptible to insect attack, and non-resistant to powder post beetles.

27

Wood Deterioration

Timbers are susceptible to rapid deterioration by variety of organisms if the prevailing

conditions around the wood are favourable to them. The wood in living trees and also in used

products would start to decay and decompose with the attack of organisms which is termed as

the biodegradation of wood (Hodgson, Beard and Deer, 2009). Fungi and insects (termites)

are the major causes of biodegradation which eventually leads to wood deterioration.

According to Goodell, Nicholas and Schultz (2003), wood degrading fungi, insects, bacteria

and marine borers cause damage(deterioration) resulting in billions of dollars being spent on

repair and replacement of wooden structures every year. The equivalent of one- tenth of the

forest products produced every year around the globe is estimated to be destroyed by these

biodegrading agents. Wong and Cheok (2001) identified biodegradation of wood by termites

as being chronic in many temperate and tropical regions of the world with very serious

consequences for the countries including Nigeria.

Termites and Infestations of Wood

Termites belong to the insect order Isoptera which means equal winged and refers to

the similar size and shape of the forewings and hind-wings (Hodgson, Beard and Deer, 2009).

Termites are most closely related to wood eating cockroaches and are some of the oldest

insects in existence. Hodgson, Beard and Deer (2009) posit that there is evidence that termites

have been in existence for about 100 million years. Termites are the only social insects with

simple metamorphosis that includes egg, nymphs and adult. All other social insects go

through complete metamorphosis that includes egg, larva, pupa; and adult. Animals, including

insects, cannot typically digest the cellulose in wood, paper, and cloth. Termites have evolved

to take advantage of this widely available food resource .They have protozoa (micro-

organisms) in their intestines which provide enzymes to digest cellulose. Although termites

are soft bodied insects, their hard, saw-toothed jaws work like shears and can bite off

28

extremely small fragments of wood until the whole susceptible wood is destroyed on account

of their infestations (Kamble, 1991).

Arang and Green (2006) noted that some of the clear indications of subterranean

termite infestations will be the appearance of shelter tubes made of soil and stemming from an

underground location near the building or wooden structures, galleries, loss of form and exit

holes. The shelter tubes protect the termites from desiccation as they travel between the soil

and their targets of attack.

Termites often infest interior of buildings and cause damage to timber, wood panels,

flooring, sheetrock, wallpaper, plastics, paper products and fabric made of plant fibres. They

also attack carpeting, art work, books, clothing and furniture; the most serious damage

involves the loss of structural strength of wood .The termites that have been identified in the

destruction of Interior wood are the subterranean and damp wood termites (Wong and

Cheok, 2001).

Subterranean termites can attack any unprotected wood or wood product. They live in and

obtain moisture from the soil. Although subterranean termites prefer the soil environment,

they will build mud tubes over exposed surfaces from the soil to wood as source of food

(Jones, Kick-Raack and Pound, 2007). The Damp wood termites on the other hand live in the

wood on which they feed and rely on the wood as a source of water. Consequently, these

termites attack only wood with a high moisture content but once established, they can extend

their activities into sound dry wood (Thomasson, 1998). The extent of damage of termites

attack can be visually inspected and rated according to the American Wood Preservers

Association (AWPA) standards E1-97(1999), American Society of Testing and Materials

(ASTM) standards D1758-06 and the NORDIC countries standards EN 252(2006). In the

rating process according to Lee, Wu and Smith (2003) three or five raters may be engaged by

the researcher to rate the wood samples after the infestation period using indicators such as

29

the presence of shelter tubes, galleries, loss of form and shape, exit holes, dull sound of wood

when tapped and hollowness of wood when poked with sharp instrument. The mean index of

the ratings is used to determine the extent of termite infestations.

Wood Preservation in Nigeria and Plateau State

Wood preservation in Nigeria has been around for millenniums predating the modern

methods of preserving wood which began at London in 1938 with John Bethel setting the

pace for such technology. Wood preservation on the African continent is varied. Some

practices markedly differ from those in the Americas and Europe (Freas, 2011). In Nigeria,

measures against termite infestation range from traditional methods and commercial services

to physical removal of nests by hand. Yet some control procedures are similar to those

reported in the Americas and Europe, including soil applications (topical and injection) with

the usual range of termiticides, as well as baiting. Preservative manufacturers have a long

tradition of being at the forefront of research and development. The timber preservation

industry is facing challenges on a scale never seen before. These according to Currie (2010)

include adaptation of new approaches to service life prediction and standardization, ensuring a

level playing field for comparisons with modified wood and other competing technologies,

managing a transition to regulation at a new level and a higher cost and finally in ensuring

strategies for developing alternative preservatives that are humanly and environmentally safe

as traditional methods are replaced.

Traditional methods of preserving wooden farm implements, wooden hunting

weapons, wooden plates, dishes and bowls, wooden poles for roofing, chieftaincy staff,

masks, pestle and mortars, drums, wooden flat beds, palace doors and several other usages

have been in practice before the advent of the modern processes of treating wood across the

different cultures in Africa, Nigeria and of course Plateau State in particular. The traditional

practice of treating wood as captured by Kumar and Shukla (1994) which is common to most

30

Nigerian communities involves smoking of wooden poles for the truss in roofing local houses,

oiling and firing of walking sticks and staff, immersing timbers in water-ways for storage and

preservation purposes (soaking timbers will facilitate leaching of starch and sugar which are

the main attraction for insects), sprinkling wooden utensils with liquid extraction from

bark/leaves of some trees. Other traditional methods used in preserving wood is the

application of mixture of spent engine oil and kerosene whose efficacy in protecting wood

against termite infestation has been confirmed through a study conducted by Olaniran,

Olufemi and Oluyege (2010).

A major draw back however of spent engine is its devastating effect on the environment as is

the experience in the Niger Delta area of Nigeria on account of oil spillage. In addition to the

traditional methods of preserving wood in Nigeria, the conventional methods of treating wood

are used by various wood industries and building construction practitioners. Some of the

preservatives used according to Ezeji (1984) and Freas (2011) include paints, water-repellent

stain, DDT, Aldrin, Solignum, coal tar, creosote oil to retard the effects of weathering,

moisture movement, fire, fungal attack and insect attack. Chromated copper arsenate

(CCA) mixtures have been shown to offer good protection to soft woods in Nigeria over long

periods of service, being highly effective against both fungal decay and insect attack. CCA is

widely used in Nigeria but because most wood users in the country do not have access to

vacuum or pressure treatment cylinders, the preservative is applied by immersion.(Adetogun

& Omole, 2007).

Toxic Preservatives and Treatment Methods

Many commonly used wood species can deteriorate if exposed to conditions that

support growth of wood- degrading organisms. Wood products can be protected from the

attack of decay fungi, harmful insects, or marine borers by applying chemical preservatives

(Lebow, 2006). Preservative treatments greatly increase the life of wood structures, thus

31

reducing replacement costs and allowing more efficient use of forest resources. The degree of

protection achieved depends on the preservative used and the proper penetration and retention

of the chemical. Wood preservatives must meet two broad criteria: (1) they must provide the

desired wood protection in the intended end use, and (2) they must do so without presenting

unreasonable risks to people or the environment (Edlund et al, 2006; Lebow, 2006).

Toxic wood preservatives according to Porter and Rose (2007) are generally classified into

three main groups:

Organic-Solvent types

Water-borne types

Oil-based types

Organic-Solvent Preservatives

These preservatives use medium of organic solvents to transmit the toxic chemicals

into the wood and can last multiple of years from a single coating. After application the

solvents evaporate, leaving the wood toxic to fungi and insects. The solvents used in the

preparation, such as white spirit, are generally volatile and flammable but do not affect the

dimensions of timber i.e. causing swelling (Lenow, 2006; Porter, 2001). Examples of organic-

solvent preservatives are Chlorinated phenols and Sodium Pentachlorophenol. The methods of

treatment used for organic-solvent preservatives are the low pressure (double vacuum) and the

non-pressure (brushing, spraying and dipping/immersion) methods.

Water-Borne Preservatives

These types of preservatives use water, a low cost carrier to convey the chemicals into

the wood and are often used when cleanliness and paint ability of the treated wood are

required. Some of these water-borne preservatives change the wood into green colour which

sometimes hinders the use of transparent finish (Porter and Rose, 2007; Goodell, Nicholas and

Schultz, 2003). Examples of water-borne preservatives according to Lenow (2006) are Copper

32

Chrome Arsenic (CCA), Acid Copper Chromate (ACC), Ammoniacal Copper Zinc Arsenate

(ACZA). Wood preservatives based on copper chromium and arsenic compounds are used

world wide to protect wood from wood destroying insects and fungi in most environments.

However, due to human health and environmental concerns, the use of preservatives with

arsenic and chromium has been restricted (Edlund, 2006). The wood and building industries

according to Matias and Lorella, (2006) have long used timber treated with chromate copper

arsenate (CCA) but aware of the risks of arsenic, a highly toxic metal and known carcinogen

present in CCA, manufacturers of wood preserving chemicals voluntarily agreed to phase out

CCA products in December 2003. These preservatives are applied using the pressure method,

usually the empty cell process to ensure thorough penetration of the chemicals.

Oil-Based Preservatives

Oil-type wood preservatives are some of the oldest preservatives, and their use

continues in many applications. Lenow (2006) asserts that wood does not swell from

treatment with preservative oils. Creosote and other solutions with heavy, less volatile

petroleum oils often protect wood from weathering but may adversely influence its

cleanliness, odour, colour, paintability, and fire resistance ability. Wood treated with some

preservative oils can be glued satisfactorily, although special processing or cleaning may be

required to remove surplus oils from the surfaces before spreading the adhesive. Other

examples of oil based preservatives include Coal- Tar, Solignum and petroleum solutions of

pentachlorophenol, tung oil, linseed oil. Some of most popular chemical oil based

preservatives used in Nigeria and by extension Plateau State are coal tar, creosote oil and

solignum (Ezeji, 1984; Bamiro, Nurudeen and Akunu; 1986). The inherent health hazards

associated however with the use of oil based chemical preservatives according to the

European Union Commission (2001) include gastro intestinal tract infection, respiratory tract

33

infections, severe cornea eye injury including conjunctivitis and prolonged skin exposure to

the chemicals can lead to skin cancer in some cases.

The method of applying oil based preservatives using brushing and dipping is the

simplest method according to Su et al (2002); adding that the method is used on a large scale

on many occasions due to its simplicity, rapid treatment time and effective in some wood

species against termite infestations.

The evaluation of the effectiveness of new preservatives however is required to meet

standards as provided for by various countries or international supervision agencies for

example the International Research Group on Wood Preservation (IRG/WP), American Wood

Protection Association (AWPA), British Wood Protection Association (BWPA), Nordic

Wood Preservation Council (NWPC), Federal Nigeria Environmental Protection Agency

(FEPA) and several other standards. For example the test for preservative effectiveness on

wood by the AWPA E1-97(1999) stipulates that a field and laboratory tests over a period are

required to approve a preservative for ground contact wood use while NWPC EN 252(2006)

accepts the use of either test results from the field or the laboratory for such approval

depending on the type of preservative used and the location of the field (NT Report, 2006 and

AWPA manual, 1999)

Alternative Low and Non-Toxic Preservatives

The ban on the use of water-borne CCA and the increasing restrictions on traditional

oil borne chemicals such as pentachlorophenol, coal tar, creosote and solignum; new

preservatives and wood protecting systems that can replace these older chemicals must be

developed. Goodell, Nicholas and Schultz (2003) assert that environmental concerns, safety

of human lives, disposal issues and public perceptions are directing researchers and the wood

industry to develop environmentally acceptable methods to protect wood. They opined that

the problem is to better understand how wood deteriorating organisms attack wood so that

34

they may be safely controlled, yet allow the wood product to be safely disposed of or recycled

at the end of the product‟s life.

Matias and Lorella (2006) indicate that alternatives for the commonly used CCA have

been found in chemicals such as alkaline copper quaternary and copper- azole and copper

naphthenate but their major drawback is that they are expensive. They claim that with the

withdrawal of CCA treated wood for residential use in the U.S., Canada and EU countries,

there is a potential market of 68 percent to be filled by other viable, cost-effective alternative

preservatives. Some of the pesticides that have been developed by several companies in the

U.S. as listed and recommended by the US Environmental Health Coalition (EHC) for use

by home owners for the control of termites include Allethrin d-trans, Bifenthrin, Cyfluthrin,

Deltamethrin, lmiprothrin, Prallethrin, Pyrethrins and several others. These chemicals have

been found to have tolerable levels of toxicity for use as preservatives in homes.

Neem Tree (Azadirachta Indica A. Juss) and its oil

The neem tree, Azadirachta indica, is a tropical evergreen with a wide adaptability.

Native to India and Burma, it has been transplanted to Africa, the Middle East, South America

and Australia (Giger, 2001). It is especially suited to semi-arid conditions and thrives even in

the poorest soil with rainfalls as little as 18 inches (450 mm) annually and temperatures up to

50° C (120° F). It may grow up to 50 feet (15 m) tall and live for 200 years. In Africa the tree

is used as a shade tree and as a source of fuelwood while in Guinea and Sahel savannah

countries including Nigeria , neem as been used for halting the spread of the Sahara desert

(Keay, 1989). It is also a preferred tree along avenues, in markets and near homesteads,

because of the shade it provides. The relatively hard and heavy wood of neem is not only

durable, but also termite resistant. In many developing countries the wood is used in making

fence posts, poles for house construction and furniture. A neem tree generally begins bearing

fruits at three to five years of age, and can produce up to 50 kg (110 lbs.) of seeds annually

35

when mature from which the oil is extracted. Neem seeds contain up to 45% of brown and

bitter oil, which is also known as Oil of Margosa(Giger, 2001).

In many areas in Plateau State, the neem seeds are easy to collect from the ground

because birds or fruit bats eat the juicy and sweet fruits and spit out the kernels. If this is not

the case the harvested ripe fruits need to be pulped in order to obtain the seeds for further

processing to produce the oil (Usman, 2011).

Giger(2001); Bawa, Orunmuyi, Agbaji, Ladan and Okekeifi(2007) identified two major

methods of processing neem oil which include the solvent extraction and cold press methods.

They noted that the cold press method is the most potent of extracting neem oil used even by

the local people where modern technology of extraction is yet to be practiced.

The cold press method of extracting neem oil as itemized by Giger (2001) is as follows:

Gather the fruits and pulp them to remove the flesh

Wash the kernels if possible to avoid fungal infection

Dry the kernels in the sun

Crush the kernels in a fufu mortar (because of the bitter taste, use a separate mortar)

Remove the shells of the kernels by winnowing, as done with cereals

Grind the kernels in a mortar until a powder is obtained

Moisten the powder with a little water and form a dough-ball

Knead the ball until oil collects on the surface

Press the oil out

Repeat steps 8 and 9 until you obtain about a third to half a small bottle of oil per kg

of crushed kernels.

According to Ramasamy (2011), neem oil has potency not only to control wide spectrum of

biodegradable agents but itself degradable making it safe for the environment and has very

low mammalian toxicity with implications also for safe use by humans.

36

2. Theoretical Framework

A theory consists of concepts, constructs, principles and prepositions that serve a body

of knowledge. Hornby (2010) defines theory as formal set of ideas that is intended to explain

why something happens or exists. Encarta Microsoft English Dictionary (2008) also defines

theory as rules, ideas, principles and techniques that apply to a subject; it is a set of facts and

propositions analyzed in their relation to one another and used, especially in science to

explain phenomena.

It would seem that from the various definitions of a theory that the function of theories

is to guide practice and lead to application of knowledge to solve real world problems. The

theoretical framework upon which this study is based is the theory of wood preservation and

the theory of penetration/retention of preservatives.

Theory of Wood Preservation

According to Koski(2008), wood preservation theory is hinged on the principle of

toxicity i.e. elimination of suitable nutrition for biodegrading organisms such as termites,

bacteria, fungi and marine borers. The theory also states that impregnation with biocides

containing creosote, arsenic, zinc, copper or chromium, for example will prevent favourable

biological degradation conditions for the destructive agents to thrive. The application of this

principle for wood preservation dates back as far as 2000 B.C. and the process was patented

for the first time by John Bethell in 1938 with the pressure process wood treatment in which

wood was impregnated with creosote thereby making it toxic as source of food for

biodegrading organisms and at the same time preventing other biological degrading

conditions such as favourable moisture, temperature and the presence of oxygen.

The wood preservation theory relates to the possibility of neem oil to seal the wood

pores and cells thereby preventing the absorption of moisture thus maintaining the dryness of

37

wood (moisture content not exceeding 20% of its oven dry weight) and thereby preventing

attack by termites. It also relates with the likely-hood of neem oil to make wood non-

nutritious thereby stopping the feeding pattern of termites and thus preserving the wood from

infestation. The prevention of wood degradation using neem oil is also based on the idea of

interfering with the basic physiological requirements for the growth and development of

micro-organisms, and insects.

Theory of Penetration/Retention of Preservatives

The theory of penetration and retention of preservatives as postulated by Coleman

(2000) is predicated upon “the need to obtain good penetration of preservative into the wood

cells which equals the performance of wood in resisting degradation agents and prolonging

the years of service of the wood”. The theory also states that “a preservative that has good

wood penetration should have good retention quality without leaching (depletion of

preservative into the environment)”. The leaching of the preservative has implication for the

environment through contamination of water ways and destruction of the biodiversity if

preservative is highly toxic. The depletion of the preservative also reduces the ability of wood

to resist infestation by termites and other degradation agents.

The theory of penetration and retention of preservative relates to neem oil‟s high rate

of penetration of wood even with the application method of brushing with two coats of

preservative. The depth of penetration and retention of preservatives depends on the type and

species of wood and in this study, timbers that allow for good penetration and retention of

preservatives have been selected for use. Neem oil congeals with low temperature therefore

its use as preservative in Plateau State with temperate like weather will increase its retention

level without leaching.

38

Theory of Osmotic Pressure Treatment

The theory of osmotic pressure treatment is based upon the natural law of pressure

which causes the passing of a solution of high concentration into the solution of lower

concentration when the two are separated by a semi-permeable membrane. This osmotic

pressure, a physical law as well established as gravity drives the preservatives into the wood.

The discovery of osmotic pressure is credited to Van't Hoff. Kingsland (2011) traced the

development of the theory to about 1880 in which the soluble substances obey the gas laws.

Hence, osmotic pressure as defined by Hoff in Kingslands (2011) is the hydrostatic pressure

which brings two solutions of different concentration into equilibrium when separated by a

semi-permeable membrane. The existence of osmotic pressure is revealed to us through many

natural appearances. Osmotic pressure in wood cells as noted by Kingsland has registered

over 325kg/mm2

when measured. Under ordinary circumstances, this pressure is sufficiently

powerful to enable plants and trees to split rocks and cement and to lift houses. It is this same

power-packed action which forces the wood preservatives into the wood cells.

The wood preservative if supplied in powder form is mixed with water thereby

forming a viscous paste of predetermined density or alternatively the preservative is

purchased already prepared and the treatment is performed right on the job. Thus, the

expenses of shipping the wood to a centralized treating plant as well as the cost of the return

freight are eliminated. The concentrated paste or solution is then applied to the surfaces of

green wood which is clear of inner and outer bark. Then the coated wood is stacked in a very

close pile and covered with waterproof paper or plastic covering material. This covering is to

prevent the rain washing off the paste and to retain the moisture in the pile until the

preservatives have penetrated beneath the surface of the wood. The penetration of the

preservative into the wood cells usually takes from two to three weeks when the paste is

applied. As soon as the treated wood is close piled, the Law of Osmotic Pressure immediately

39

begins to function when the toxic salts of the preservative are carried through the wood cells

as far in as there is moisture, in green wood this can be 50mm or more. The sodium fluoride

penetrates the farthest while the insoluble dinitrophenol affixes to the wood fibres in the outer

areas of the wood. The potassium bichromate combines with a portion of the sodium fluoride

to form a non-leachable chromation layer which also affixes to the wood fibres. In this

manner two insoluble, toxic compounds are formed around the outer reaches of the treated

wood. In doing so they afford a water-repelling coating on the outside of the wood while the

sodium fluoride remains in the inner extremity of the preserved portion to insure adequate

toxicity from the inside. As most of these chemicals are colorless, the depth of penetration is

calculated with the aid of chemical coloring reagents while those preservatives with color will

always show depth of penetration in the wood particularly the oil base ones.

The osmotic pressure technique combines a superior capacity to destroy fungi and

insects while retaining complete neutrality to metals. Included in these wood preservatives are

such chemicals as sodium fluoride, dinitrophenol, potassium bichromate, and disodium

hydrogen arsenate.

It thus appear that since neem oil shall be applied on the wood samples using the

brushing method and not using the full pressure or empty cell methods, the osmotic pressure

will act between the surfaces of piles of treated wood samples to cause the penetration of the

oil into the cells before the samples are exposed for termite infestation.

3. Review of Related Empirical Studies

Several empirical studies have been undertaken all over the world since the beginning

of the use of chemical wood preservatives about two centuries ago. Some of the studies were

specific on the various types of the preservatives whilst others were on the combinations of

the preservatives all with purpose of providing wood with the required protection for long

service years. Goodell, Nicholas and Schultz (2003) captured the essence of the use of wood

40

preservatives when they stated that “historically, humans have battled wood deterioration

agents through the ages with chemical treatments but that environmental and human health

concerns have recently dramatically changed the way wood preservative chemicals are

viewed”.

In an attempt to develop an effective and environmentally friendly preservative, Su et

al. (2002) carried out a study at Guangdong Academy of Forestry in China on the use of

concentrated borate (SGB) as wood preservative against termites and fungi. In the study,

wood samples of pinus massoniana lamb with dimensions of 25×25×6mm3

each were

selected for a laboratory (indoor) test according to the American Wood Preservers‟

Association Standard AWPA E1-97. In the preparation for the test, some wood samples were

treated with SGB using the brushing method of applying two coats of SGB with time interval

between coats while some samples were left untreated as the control group. The two groups

were exposed to subterranean termites for the period of the experiment. At the end of the

experiment, the results showed that SGB treated wood had high resistance of grade 10 to

termite or decay while resistance of control group was 0. Weight loss of control group was

52% while the treated group had less than 10%.In the same experiment, 10 mice were given

oral administration of 5050mg/kg doses of SGB and observed for 14 days but survived hence

the grade of toxicity of SGB was considered of low grade. This result also showed that

concentrated borate solution is an environmentally safe preservative and can be used in non-

pressure (brushing) method of wood treatment.

In an earlier study conducted in 1990 by Poseidon Sciences Group based in New

York, USA as reported by Matias and Lorella(2006); the study aimed at identifying a wide

variety of natural bio-chemicals, selection of compounds that had the potential for further

development, their impact on the environment and safety for human handling. In the

preparation for the study, a derived compound from Mentol known and labeled as Mentol

41

Propyleneglycol Carbonate (MR-08, MPC) demonstrated a high level of efficacy as a

repellent against a variety of insect species. In the experiment, pre-weighed wood samples

were immersed in MR-08 solution for 24 hours, air-dried and placed on a termite mound

under ambient natural outdoor (exterior) conditions for two weeks. At the end of the test

period, the wood samples were cleaned of debris and termites, air dried and weighed. Wood

preservation was determined by the amount of weight loss during the test period. The findings

of the study showed that untreated (control) group had 66.3% weight loss while the treated

group had weight loss of 2.8% due to termite infestations. As a termite repellent; MR-08 also

demonstrated a prolonged inhibition of termite infestation when the period of testing was

extended to four months even when wood samples were treated with single superficial

impregnation of various concentrations of MR-08.

In another study undertaken by Manzoor, Sheikh and Zawari (2010) in Pakistan, the

resistance of four different woods of commercial importance i.e. Dalbergia sissoo,

Azadirachta indica, Populus deltoides and Pinus roxberghii was evaluated against

subterranean termites in field as well as laboratory trial. For field trials each wood was cut

into 2cm×2cm×2cm (L×R×T) dimensions, oven dried for 24h at 60°C and weighed prior to

trial. For Choice feeding trials, the wooden blocks were arranged in a group of four woods,

tied with copper wire and installed in the experimental termite mount in triplicates at a depth

of 15-20cm below the surface of the soil. The replicates were installed at a distance of 2m

from each other. After one month the experimental setups were recovered from the soil,

cleaned, oven dried and re-weighed to determine the mass loss. In addition, wood specimens

were visually rated according to the (AWPA, 1997): and were graded from 10(sound, surface

nibbles permitted), 9 (light attack), 7 (moderate attack), 4 (heavy attack), or 0 (failure). The

data obtained from the study were presented as mean weight loss due to termite attack; mean

visual rating to describe the extent of wood damage caused by the termite and percentage

42

mortality of the termites in laboratory trials. In choice field trials P. roxberghii was very

resistant (VR) with 10 visual rating, A. indica was resistant (R) with 9 visual rating, D. sissoo

was moderately resistant (MR) with 7 visual rating and P. deltoides was susceptible (S) to

termite attack. One way ANOVA analysis revealed that mean weight loss of different woods

were significantly different from one another (F=7.850; P<0.001).

In India, Verma, Sharma & Prasad conducted a study on the use of leafy biomass of

plants to control termites compared with a chemical preservative known as Chlorpyriphos.

Findings of the study after four weeks of exposure of both treated and untreated Pinus Excels

wood blocks inserted into termite infested area showed that:

Out of the 14trees and plants‟ leafy extracts used, Cannabis Sativus caused the most

significant protection with 4.94% of Pinus Excelsa wood weight loss; Azadirachta

Indica had15.77% weight loss of wood while the least protection for wood was observed

of Jatropha curcus with 51.17% weight loss.

The chemical preservative Chlorpyriphos gave 100% wood protection with no weight

loss of wood samples.

The untreated control group had 100% weight loss with termites consuming the wood

samples.

The conclusion of the report showed that extracts of plants and trees if further

developed may provide effective preservatives as the chemical preservatives with the added

advantages of being safe for humans and the environment; they are degradable and renewable

resources. The study also showed that other extracts of plants and trees other than the leaves

could be exploited as sources of effective wood preservatives.

In Nigeria, a study was conducted by Adetogun, Adegeye and Omole (2009) on the

evaluation of Cashew-nut Shell Liquid (CNSL), a plant derivative as wood preservative using

weight loss method for assessment of the efficacy of CNSL. In the experiment, test blocks of

43

Triplochiton Scleroxylon (Obeche) wood were treated with different concentration levels of 4,

8, 12, 16, 20, 24, 28 and 32% of CNLS using pressure impregnation method which resulted

into substantial penetration and absorption of CNLS. The treated test wood blocks were

thereafter exposed to micro-organisms for 16 weeks of infestation and at the end of the

period, CNLS was found to prevent wood weight loss at concentration above 8%. The

efficacy of CNLS at various concentrations in protecting the test wood blocks against

biodegradation by the test was evaluated from the following formula:

Dw1- Dw2 × 100

Dw1 1

Where:

Dw1 = Weight of test blocks before experiment

Dw2 = Weight of test blocks after experiment.

In examining the test blocks after the infestation period, colour changes and degree of

softening were used as parameters of decay assessment based on the visual method of rating.

Ratings were allotted to indicate the protective ability of each treatment level on the wood;

four ratings of 6, 4, 2 and 0 were used. The data collated were then analyzed using 2-way

analysis of variance and tested at significant level of p<0.01. The results of the test showed

that the concentration levels which the preservative CNLS was applied were highly

significant hence effective in preserving wood from micro-organism infestations.

4. Summary of Review of Related Literature

The review of literature related to this study revealed that extracts from trees and bio-

organic preservatives are being developed as alternatives to chemical preservatives for wood

preservation in other countries and in Nigeria too, which the present study seeks to do.

The review also showed that measurement of weight loss of wood and visual

inspection of wood has been used as parameters for determining the deterioration of wood due

to termite infestations. Laboratory and field tests were carried out to establish the resistance of

44

wood to termite infestations in different environmental (interior and exterior) conditions and

the present study intends to adopt the field tests method in collecting data for the

determination of the extent of termite infestation.

Some of the studies reviewed showed that different wood species even though treated

with the same quantity of preservatives, when exposed to the same termites infestation areas

had different resistance levels, the present study intends to apply the same quantity of neem

oil on four different wood species that are predominant in Plateau State and there after to

determine their resistance to termites infestation.

It thus appeared that in the search for the use of non- toxic plant organic preservatives;

no studies known to the researcher had been carried out to determine the effect of neem oil for

the wood preservation of Canarium Schweinfurthii, Ceiba Pentandra, Isorberlina Doka and

Daniellia Oliveri in Plateau State and this gap was what this study intended to fill.

45

CHAPTER III

METHODOLOGY

The chapter describes the methods, procedures and materials that were used in

carrying out the research. The research design, area of study, material for sample collection,

methods of sample collection, sample preparation, treatment of samples, installation and

placement of samples, methods of data collection and method of data analysis were also

described.

Design of the Study

The research design employed in the study was Research and Development (R & D).

The main thrust of R& D design according to Gall, Gall and Borg (2007) and Nworgu (2006)

is aimed at developing products and field testing the products to confirm their efficacy before

use. Uzoagulu (2011) saw R&D as twin words that go together to the extent that research

appears to be the most effective means of knowledge development. Although costly and

demanding, R&D activities provide valuable means of not only developing new products but

improving on existing ones for wider usage and applications. Adeyemi in Uzoagulu (2011)

asserted that product development is the application of research to the upgrading of the

existing product or development of a new one. It is evident from these definitions that R &D

is about discovering new knowledge about products, processes and services, and then

applying that knowledge to create new and improved products, processes and services that fill

market needs.

Gall, Gall and Borg (2007) identified five stages that are involved in a R&D project

and these are:

Define the problem/need as clearly as possible

Analyze the need to generate alternatives and select from among alternatives

43

46

Design/develop the most viable and optimal solution mix

Conduct an implementation field test

Evaluate and revise the product based upon information and results.

The design was found appropriate for the study since it focused on developing new products

or finding alternative applications for a product. Neem oil had been used for different

applications and new use of neem oil was explored as treatment for wood against termite

infestation of predominant local timbers in Plateau State.

Area of the Study

The area of the study was Plateau State and covered eight Local Government Areas.

Canarium Schweinfurthii(Atile), Ceiba Pentandra(Rimi), isorberlina Doka(Doka) and

Daniellia Oliveri(Maje/Achuwale) trees are predominant in those areas and are used for

various wood constructions. These timbers were found susceptible to termites and other

agents of wood degradation (Scheffer &Morell, 1998 and Keay, 1989). It was noticeable that

in these areas, there was high prevalence of termite infestations which led to material loss,

loss of property, risk to human lives and the environment (See Appendices B and C).

Materials for Sample Collection

Materials that were used for the collection of the samples were: measuring rule/ tape,

try-square, pencil, rip-saw, cross-cut saw, sack, 20kg ×50g sensitive weighing scale, 25mm

hand brush and open oil can. The 3- meter measuring tape was used for measuring length of

wood samples cross cut or ripped. The try square was used to guide the measuring and

marking of the width and short length of wood samples that were cross-cut; the same

instrument was used in drawing perpendicular lines to the edge of wood samples. The pencil

was used to indicate marks for ripping and cross-cutting of wood samples. The rip-saw was

used to cut along the grain of planks following the width line marks while the cross-cut saw

47

was used to cut across the grain of the planks. The jute sack was used to collect the cut wood

samples from the timber shades of various areas of study and conveyed to the researcher‟s

workshop. The weighing scale was used for pre-weighing and post- weighing the treatment

and control wood samples. The 25mm hand brush was used for the application of neem oil on

the treatment groups while the open Oil Can was used as the receiver of neem oil from the

bottles before application on wood samples.

Methods of Sample Collection

Forty-eight pieces each of Canarium Schweinfurthii(Atile), Ceiba Pentandra(Rimi)

Isorberlina Doka(Doka) and Daniellia Oliveri (Maje/Achuwale) measuring

12.5mm×50mm×300mm were cut from defect free parts of the timber obtained from various

timber shades of the area of the study. Twenty-four pieces each of the wood sample species

(making a total of 96 pieces) were randomly selected from the 192 pieces of defect free wood

samples cut from the timber. The selection of these timbers was based on the fact that

Canarium Schweinfurthii(Atile), Ceiba Pentandra(Rimi), Isorberlina Doka(Doka) and

Daniellia Oliveri(Maje/Achuwale) timbers were widely used for various wood/ building

construction in Plateau State and were susceptible to termite infestation. Twelve 100ml bottles

of processed neem oil were purchased from the local markets in Plateau State for the

treatment of the experimental group.

Preparation of Samples

Ninety-six pieces of wood samples comprising 24 pieces each of Canarium

Schweinfurthii (Atile), Ceiba Pentandra(Rimi), Isorberlina Doka(Doka) and Daniellia

Oliveri(Maje/Achuwale) were prepared in accordance with the American Wood Preservers

Association(AWPA)E1-97[1999] and Nordic Wood Preservation Council(NWPC)

EN252[2006] standards for the field trial tests. All the wood samples were oven dried to

48

ensure that the moisture content of each sample is not above 20%. The reduction of the

moisture content was to facilitate easier absorption and penetration of the preservative in the

wood samples. All the wood samples were randomly allotted numbers, labeled with the first

letter of the wood specie type and either UT or T indicating untreated or treated sample; for

example A1- TI on wood sample meant Atile No.1Treated Interior or A16-UTE meant Atile

No. 16 Untreated Exterior. The labeled wood samples were then randomly selected and

grouped into two, treatment and control (48 pieces in each group). Each wood sample in the

two groups was then weighed for its pre-infestation weight using the sensitive weighing scale

and values of the pre-infestation weights recorded (See Appendix D).

Treatment of Samples

Twelve pieces of wood which was 50% of each sample specie of Canarium

Schweinfurthii (Atile), Ceiba Pentandra(Rimi), Isorberlina Doka(Doka) and Daniellia

Oliveri (Maje/Achiwale) randomly selected were treated with neem oil using hand brushing

method of application. Two copious coats of neem oil were applied with 24 hours in between

coats which enabled penetration and drying of the treatment. All the treated samples were

then air dried for two days and weighed to ensure that the absorption of the oil treatment did

not significantly affect the pre-test weights of the samples (See Appendix E).

Installing and Placement of Samples

Two termite infested locations both exterior and interior environments were chosen in

Vom area in Jos South LGA of Plateau State because it was an area with high rate of termite

infestations and for close monitoring of the field test trial of both treated and untreated wood

samples. A termite mound for the exterior infested environment was identified and dug to a

depth of 15cm to ensure contact with termite activity and protect wood samples from curious

passers by while the roof trusses of a motor garage infested with termites were used for the

49

interior environment. A total of 48 wood samples comprising all the treated and untreated

species were randomly installed inside the termite mound and buried while another group of

48 treated and untreated wood samples were placed on the plates and beams of the motor

garage trusses according AWPA E1-97 and NWPC EN 252 standards of field testing of the

effectiveness of wood preservatives. The placement of the samples in both interior and

exterior locations were mapped and recorded in order to assist the researcher to recover the

samples with their appropriate labels. The wood samples both treated (experimental) and

untreated (control) were allowed for a period of six months between June 2011 and December

2011 (a period within which termite infestation is very high) before they were retrieved for

weighing and visual rating (See Appendices G and H).

Methods of Data Collection

Data was collected based on field experimental research principles through

observation (visual inspection), weighing of samples and recording of values. Pre-infestation

weights of wood samples were measured using a sensitive weighing scale and the values

recorded before exposure of samples to termite infestations. Post-infestation weight of wood

samples after six months of infestation were measured and values also recorded (See

Appendix G).

Data on the extent of infestation and deterioration of wood samples for the study were based

on a 5- point visual inspection rating adopted from the American Society for Testing and

Materials (ASTM), International D1758-06 (2010) standards of rating wood for deterioration.

The rating was done after the period of six months of infestation by three raters who are

experts in Woodwork and Building Technology (see Appendix H). Each of the pieces of

wood exposed to termite infestation was observed and rated based on the 5-point ASTM

Durability Rating Scale as shown:

50

A 5-Point ASTM Durability Rating Scale

Visual Rating

Scores

Real Limits

Description

10

9

7

4

0

9.6- 10

8.1- 9.5

5.6- 8.0

2.1- 5.5

0- 2.0

Sound Timber, No Termite Attack

Trace of Termite Attack

Moderate Termite Attack

Heavy Termite Attack

Destructive Termite Attack

Figure 2: Culled from the International Research Group on Wood Protection (2010)

Methods of Data Analysis

Pre-infestation weights of all wood samples were first recorded and then the post-

infestation weight values after the period of experiment were also taken. Percentages and

mean weight losses were calculated from the pre-infestation weight and post-infestation

weight values to determine the effectiveness of neem oil in preserving the wood samples from

wood weight losses as a result of termite infestations. Values from the visual inspection

ratings of the wood samples were also collated to arrive at the mean values on the extent of

deterioration and these data was analyzed using the mean statistics, t-test analysis was used to

compare between means of the untreated and treated samples while one-way analysis of

variance (ANOVA) was used to analyze difference in mean values within the four wood

species at p<0.01 level of significance.

51

CHAPTER IV

PRESENTATION AND ANALYSIS OF DATA

In this chapter, the data obtained from the pre-infestation and post-infestation mean weight

and percentage losses of wood samples and the mean visual ratings of wood samples are

presented in tables according to the research questions. The first part of the chapter presents

the result of the data analyzed and the second part discussed the results based on the findings.

Research Question 1

What is the weight loss of termite infested untreated wood?

To answer this research question, all the post-infested weights of the untreated four wood

species were each subtracted from the pre-infested weights to obtain the weight loss and each

total weight loss of each specie divided by 12 to obtain the mean weight loss for that specie.

(See Appendices I, J, K and L)

Summary results of the mean and percentage weight loss of the four different wood species

namely Atile (Canarium Schweinfurthii), Rimi (Ceiba Pentandra), Doka (Isoberlina Doka)

and Maje(Daniellia Oliveri) are as presented in Table 1.

Table 1

Mean and Percentage Weight Loss of Termite Infested Untreated Wood Species

S/No. Wood

Specie

N Pre-Inf.

Mean Wgt

(g)

Post-Inf.

Mean Wgt

(g)

Mean

Weight

Loss (g)

Percentage

Wgt Loss

1. Atile 12 200 47.50 152.50 76.3

2. Rimi 12 150 19.60 130.40 86.9

3. Doka 12 250 190.90 59.10 23.6

4. Maje 12 200 123.40 76.60 38.3

Key: Pre-Inf.= Pre-infested

Post-Inf.= Post-Infested

Wgt = Weight

g = grammes

Data in Table 1 show that Atile (Canarium Schweinfurthii) had a mean weight loss of

152.50g ( the difference between pre-infestation weight and post infestation weight), which

49

52

represents 76.3% of the initial mean weight of the samples of this specie. Rimi (Ceiba

Petandara) had a mean weight loss of 130.40 g of the initial mean weight of 150g; this mean

weight loss is 86.9% of the initial mean weight of the samples of the specie. Doka

(Isorberlina Doka) had the least mean weight loss of 59.10g which is 23.6% of the initial

mean weight of the samples of the specie. Maje (Daniellia Oliveri) had 76.60g mean weight

loss which is 38.3 % of the mean of the pre-infested weight.

Research Question 2

What is the effect of neem oil on the weight loss of termite infested treated wood?

The data that answer this research question are presented in Table 2.

Table 2

Mean and Percentage Weight Loss of Termite Infested Neem Oil Treated Wood

S/No. Wood

Specie

N Pre-Inf.

Mean Wgt

(g)

Post-Inf.

Mean Wgt

(g)

Mean

Weight

Loss (g)

Percentage

Wgt Loss

1. Atile 12 200 150.40 49.60 24.8

2. Rimi 12 150 103.30 46.70 31.1

3. Doka 12 250 227.50 22.50 9

4. Maje 12 200 176.50 23.30 11.7

Key: Pre-Inf.= Pre-infested

Post-Inf.= Post-Infested

Wgt = Weight

g = grammes

The results in Table 2 indicate that neem treated Atile specie had post-infestation mean

weight loss of 49.60g which is 24.8 % weight loss of the pre-infestation mean weight. The

data also shows that Rimi had a mean weight loss of 46.70g representing 31.1% of the initial

mean weight of the specie. Doka had the least mean weight loss of 22.50g which translates

into 9% of the pre-infestation mean weight while Maje had 23.30g mean weight loss which is

53

11.7% of the pre-infestation mean weight of the samples of the specie (See Appendices M, N,

O and P).

Research Question 3

What is the extent of deterioration of termite infested untreated wood?

The mean ratings of the extent of deterioration of termite infested untreated wood samples by

three raters are as presented in Table 3.

Table 3

Visual Mean Ratings and Standard Deviations of the Extent of Deterioration of

Untreated wood

S/No. Wood Specie N Mean Rating Standard

Deviation

Decision

1. Atile 12 3.60 2.64 HTA

2. Rimi 12 1.90 2.06 D TA

3. Doka 12 7.20 1.35 M TA

4. Maje 12 6.50 1.94 M TA

Key: HTA- Heavy Termite Attack

DTA- Destructive Termite Attack

MTA – Moderate Termite Attack

The results in Table 3 show that Atile had deterioration mean rating of 3.60, Rimi had the

lowest mean rating of 1.90, Doka had 7.20 while Maje recorded 6.50 deterioration mean

rating (See Appendix Q ).

Research Question 4

What is the effect of neem oil on the extent of deterioration of termite infested treated wood?

Results on Table 4 that answer the research question are as presented.

54

Table 4

Visual Mean Ratings and Standard Deviation of the Effect of Neem Oil on the

Extent of Deterioration of Termite Infested Treated Wood

S/No. Wood

Species

N Mean Rating Standard

Deviation

Decision

1. Atile 12 7.80 1.35 MTA

2. Rimi 12 7.30 1.21 MTA

3. Doka 12 8.60 1.13 T TA

4. Maje 12 8.20 1.15 T TA

Key: MTA- Moderate Termite Attack

TTA- Trace of Termite Attack

The data in Table 4 indicate that deterioration mean rating of Atile was 7.80, Rimi had the least

mean rating of 7.30, Doka recorded the highest mean rating of 8.60 while Maje had 8.20 on

the mean rating score (See Appendix R).

Research Question 5

What is the extent of termite infestation of untreated wood in exterior and interior

environments? The summary results as presented in Table 5 answer the research question.

Table 5

Mean Ratings and Standard Deviation of the Extent of Termite Infestation for

Untreated Wood in Interior and Exterior Environments

S/No. Wood Interior Exterior

Mean

Rating

Standard

Deviation

Decision Mean

Ratings

Standard

Deviation

Decision

1. Atile 5.40 2.27 HTA 1.80 1.38 DTA

2. Rimi 3.80 0.67 HTA 0.00 0.00 DTA

3. Doka 7.70 1.03 MTA 6.70 1.56 M TA

4. Maje 7.60 0.97 MTA 5.40 2.08 HTA

Key: DTA- Destructive Termite Attack

HTA- Heavy Termite Attack

MTA- Moderate Termite Attack

55

The data in Table 5 indicate that Atile in interior environment had deterioration mean

rating of 5.40 while it recorded 1.80 in exterior environment. Rimi had 3.80 mean

rating in the interior environment and 0 mean rating in the exterior environment. Doka

had 7.70 mean rating in the interior while the exterior mean rating was 6.70. Maje had

an interior mean rating of 7.60 while it recorded 5.40 as its exterior mean rating.

Research Question 6

What is the effect of neem oil on the extent of termite infestation of treated wood in

interior and exterior environments?

Table 6 is a presentation of results which answer the research question.

Table 6

Mean Ratings, Standard Deviation and t-test of the Effect of Neem Oil on

Treated Wood for Interior and Exterior Environments.

S/

N

Wood

Speci

e

Interior Exterior

Mean

Rating

Untreated

S.D Mean

rating

Treated

S.D t-

value

Mean

Rating

Untreat

ed

S.D Mean

rating

Treated

S.D t-

value

1 Atile 5.40 2.27 8.60 1.18 2.90* 1.80 1.38 7.00 1.09 7.30*

2 Rimi 3.80 0.67 8.10 0.79 10.0* 0.00 0.00 6.50 1.05 15.20

3 Doka 7.70 1.03 8.50 1.06 1.20 6.70 1.56 7.90 0.91 0.99

4 Maje 7.60 0.97 8.80 1.00 2.10 5.40 2.08 7.70 1.03 2.40

*Significant at 0.01

56

Atile had a mean rating of 5.40 for untreated interior samples as compared with neem treated

interior samples with a mean rating of 8.60 and a t-value of 2.90; Atile untreated exterior

samples recorded a mean rating of 1.80 while the treated exterior samples registered a mean

rating of 7.00 and a t-value of 7.30.

Rimi recorded a mean rating of 3.80 for interior untreated samples as against 8.10 mean

rating for the interior treated samples with a t-value of 10.00. A zero mean rating for exterior

untreated samples and 6.50 mean rating for exterior treated samples were recorded with a

significant t-value of 15.20.

Results of Table 6 also show that Doka had a mean rating of 7.70 for the interior

untreated samples as against 8.50 mean rating for the interior treated samples. Doka also had a

mean rating of 6.70 for exterior untreated samples while the exterior treated samples recorded

a mean rating of 7.90 with a t-value of 0.99.

Maje interior untreated samples had a mean rating score of 7.60 and the interior treated

mean rating of 8.80; the t-value for both the treated and untreated interior samples is 2.10. The

exterior untreated samples had a mean rating of 5.40 while the mean rating for the exterior

treated samples was 7.70 and a t-value of 2.40 for untreated and the treated exterior samples

was observed.

57

TABLE 7

One Way Analysis of Variance (ANOVA) of the Means of Difference of Treated

and Untreated Wood Species for Interior and Exterior Environments

Atile Rimi Doka Maje

df F-

Value Decision

X SD X SD X SD X SD

Treated

Interior 8.57 1.17 8.10 0.79 8.48 1.06 8.83 1.00 23 0.53 Not Sig.

Treated

Exterior 7.00 1.10 6.50 1.04 7.92 0.91 7.67 1.03 23 2.36 Not Sig.

Untreated

Interior 5.47 2.28 3.87 0.67 7.67 1.03 7.63 0.97 23 10.66 Sig.

Untreated

Exterior 1.75 1.38 0.00 0.00 6.73 1.56 5.37 2.08 23 26.97 Sig.

Key: Not Sig. = Not Significant, Sig. = Siginifcant

The result of analysis on Table 7 shows the F-value for the comparism of the

deterioration rating means for the four wood species, the treated interior samples for the wood

species had an F-value of 0.53, while the exterior treated samples of all the species recorded

an F-value of 2.36. The interior untreated samples F value was 10.66 while the exterior

untreated samples of the four species had an F-value of 26.97.

The results further reveals that all the treated samples with F- values of 0.53 and 2.36

for treated interior and treated exterior respectively did not have any significance and the

untreated samples with F-Values of 10.66 and 26.97 for untreated interior and untreated

exterior respectively had significant differences.

Findings

The following findings emerged from the study:

1. Untreated Atile wood specie had a post infestation mean weight loss of 152.50g

which is 76.3% of the pre-infestation mean weight of the specie.

58

2. Untreated Rimi wood specie had a post infestation mean weight loss of

130.40g due to termite infestation and this represents 86.9% of the pre-

infestation mean weight of the specie.

3. Untreated Doka had a post infestation mean weight loss of 59.10g which is

23.6% of the pre-infestation mean weight of the specie.

4. Untreated Maje had a post-infestation mean weight loss of 76.60g and this

represents 38.3% of the pre-infestation mean weight of the specie.

5. Neem oil treated Atile wood specie had a post infestation mean weight loss of

49.60g which is 24.8% of the pre-infestation mean weight of the specie.

6. Neem oil treated Rimi wood specie had a post infestation mean weight loss of

46.70g representing 31.1% of the pre-infestation mean weight of the specie.

7. Neem oil treated Doka wood specie had a post infestation mean weight loss of

22.5g which is 9% of the pre-infestation mean weight of the specie.

8. Neem oil treated Maje wood specie had a post infestation mean weight loss of

23.3g which is 11.7% of the pre-infestation mean weight of the specie.

9. Untreated Atile had heavy termite attack with a mean rating of 3.60 on a 5-point

deterioration rating scale.

10. Untreated Rimi had destructive termite attack with a mean rating of 1.90 on a 5-

point deterioration rating scale.

11. Untreated Doka had moderate termite attack with a mean rating of 7.20 on a 5-

point deterioration rating scale.

59

12. Untreated Maje also had moderate termite attack with a mean rating of 6.50 on a

5-point deterioration rating scale.

13. Neem oil treated Atile showed moderate termite attack with a mean rating of 7.8

on a 5-point deterioration rating scale.

14. Neem oil treated Rimi had a moderate termite attack with a mean rating of 7.3

on a 5-point deterioration rating scale.

15. Neem oil treated Doka had trace of termite attack with a mean rating of 8.6 on a

5-point deterioration rating scale.

16. Neem oil treated Maje also had a trace of termite attack with a mean rating of

8.2 on a 5-point deterioration rating scale.

17. Untreated Atile had heavy termite attack in the interior environment while it

came under destructive termite attack in the exterior environment.

18. Untreated Rimi also had heavy termite attack in the interior environment while it

experienced destructive attack in the exterior environment.

19. Untreated Doka had moderate termite attacks both for the interior and exterior

environments.

20. Untreated Maje also had moderate termite attacks both for the interior and

exterior environments.

21. Neem oil treated Atile samples placed in interior environment had traces of

termite attack while the samples placed in exterior environment had moderate

termite attack.

60

22. Neem oil treated Rimi samples placed in interior environment had traces of

termite attack while the samples placed in the exterior environment had moderate

attack.

23. Neem oil treated Doka samples placed in interior environment showed trace of

termite attack while the ones placed in the exterior environment had moderate

attack.

24. Neem oil treated Maje samples placed in interior environment had also trace of

termite attack while the samples in the exterior environment had moderate attack.

25. Treated interior and exterior Atile, Rimi, Doka and Maje samples did not have

any significant differences in their deterioration ratings

26. Neem oil treated samples for Atile and Rimi were significantly different in

termite infestation from untreated samples for both interior and exterior

environments while Doka and Maje did not show any significant difference

between the treated and untreated samples for both interior and exterior

environments.

Discussion of Findings

The findings from Table 1 provided answer to research question one and these revealed that

there were weight losses for untreated samples of Atile, Rimi, Doka and Maje wood samples.

These are wood samples that never had any type of preservative applied on them before their

exposure to termite infested areas. It was observed that there were differences in weights

between the pre-infestation weights and the post-infestation weights. The results from Table 1

showed Atile with 76.3% weight loss of the initial pre-infestation mean weight of

200g.Untreated Atile was the second most susceptible wood specie after Rimi based on the

61

results. The results also revealed that untreated Rimi wood specie was the most susceptible

with 86.9% post infestation weight loss of the pre-infestation weight of 150g.Untreated Doka

also followed the same pattern of weight loss with 23.6% post infestation weight loss of the

initial pre-infestation of 250g. With this result, Doka was the least susceptible to termite

infestation of all the four species. Untreated Maje had 38.3% weight loss of the pre-infestation

weight of 200g and ranks next to Doka in resistance to termite infestations.The weight losses

recorded by all the four wood species after post-termite infestations could therefore be

attributed to the destructive activity of termites to which they were exposed to over a period

of six months(see appendix Q).This assertion agrees with the positions of Lee, Wu and Smith

(2003) and Wong and Cheok (2001) who pinned down termites as being one of the most

destructive agents of wood with the consequence of weight loss after infestation. The details

of weight losses of each untreated wood sample after termites‟ infestation are as shown in

Appendices I, J, K and L.

The weight losses of Neem oil treated wood samples of Atile, Rimi, Doka and Maje as

shown in Table 2 answered research question 2; and these weight losses were noted to be low

compared with the untreated samples which were all exposed to the same ambient condition

and termite infested locations. The treated samples of Atile recorded percentage weight loss

of 25.2 after post termite infestation measurement as compared with 76.3% weight loss when

untreated. This result showed that resistance to termite infestation was enhanced with the

neem oil treatment being the only substance applied before exposure to termite

infestation.Treated Rimi also showed improved resistance to termite infestation when it

recorded a post infestation weight loss percentage of 30.2 as compared with the 86.9%

recorded against the untreated Rimi in post-infestation weight loss.Neem oil treated Doka

followed the same pattern of resistance to termite infestation when it recorded 9% percentage

weight loss when compared with 23.6% weight loss of untreated Doka.The trend was repeated

62

by neem oil treated Maje which had 11.8% post infestation weight loss recorded against it

compared with 38.3% weight loss of untreated Maje.The drop in weight losses percentages of

the neem oil treated species of Atile, Rimi, Doka and Maje implied that the service life of

wood is lengthened and this makes neem oil fit into the description of being called a wood

preservative as defined by wood preservative experts who described a wood preservative as

any substance that is applied on wood to increase or prolong its service life (Edlund, Evans &

Henriksen; 2006 and Thomasson, Capizzi, Dost, Morell & Miller; 1998). The details of the

pre-infestation and post- infestation weight losses of treated samples are as shown in

Appendices M, N, O and P.

The findings on Table 3 are answers to research question 3 and the results showed that

untreated Atile, Rimi, Doka and Maje suffered moderate to destructive termite infestation

leading to various levels of deterioration. Atile had a visual mean rating of 3.6 falling within

the group of samples with heavy termite infestation, Rimi had a mean rating of 1.9 which

felled into the category of samples which suffered destructive termite infestation, Doka had

moderate termite attack within a rating of 7.2 while Maje had 6.5 mean rating considered to

be within the group of samples which suffered moderate termite attack. The visual mean

rating scores of all the untreated wood samples are indicative of the fact that termite

infestation leads to different levels of deterioration which were observed in the various

untreated species and characterized by loss of form and shape, breaking apart of wood fibre,

remnants of mud shelter tubes, galleries and tunnels. The standard deviation of the mean

ratings show also that Atile and Rimi had diverging rating when compared to the mean among

the various raters which could be as a result of changes on the form and shape of the wood,

while this is not the case with Doka and Maje. The extent of attack on wood by termites

leading to its deterioration can be visually inspected and rated according to the American

Wood Preservers Association (AWPA) Standards E1-97(1999), American Society of Testing

63

and Materials (ASTM) Standards D1758-06 and the NORDIC countries Standards EN

252(2006). Hodgson, Beard and Deer (2009) had also asserted that rapid deterioration by

termites could occur if the prevailing conditions around the wood are favourable to them and

in this study such conditions were provided by placing the untreated wood samples in termite

infested car garage and in a termite mound(see Appendix B and F).

The neem oil treated samples results presented in Table 4 showed that there were

various levels of deterioration but the visual mean ratings indicated reduction of deterioration

levels of all the species with Atile and Rimi moderately attacked while Doka and Maje

showed only a trace of attack by termites. The reduction in wood deterioration could be

attributed to the neem oil treatment which was the only substance applied on the various wood

specie samples prior to exposure to the termite infested locations. It therefore follows that the

reduction in deterioration of the wood samples was because the wood samples were protected

with neem oil and this finding agreed with the position of Wong and Cheok (2001) that wood

unprotected by a preservative can be attacked by termites in any termite infested area and if

infestation is not checked can lead to deterioration with the consequence of loss of structure,

cost of replacement and even the loss of lives. Details of the mean ratings of each treated

wood samples against termite attack are as shown in Appendix T.

The results of findings on Table 5 answer research question 5. The results showed that

there were high levels of termite infestation for untreated samples of Atile and Rimi placed in

both interior and exterior environments as compared with Doka and Maje samples that had

low differences in the mean ratings of infestation for both interior and exterior environments.

It was observed that the mean rating for Rimi for exterior samples was zero which agreed

with the mean weight loss of 100% of the same samples as shown in Appendix J. This finding

implied that untreated Rimi placed in an exterior environment that is infested with termites

can be completely destroyed without a trace of the wood. Atile untreated samples followed

64

the same trend with some of the samples suffering destructive attacks by termites in the

exterior location. Location therefore is a factor in determining the level of infestation by

termites hence the preservatives to prevent termite infestations are equally developed

according location of use. This position is supported by Thomasson, Capizzi, Dost, Morell

and Miller (1998) who classified preservatives according to how and where they are used

either for interior or exterior use; noting further that preservatives are developed according to

the location of use; for example preservatives used for ships on high seas are different from

those used for residential buildings on land.

The results of findings on Table 6 pinned down the significant differences that

occurred between the untreated and treated wood samples in exterior and interior

environments. Atile had a t-test value of 2.9 for interior untreated and interior neem oil treated

while it recorded t-test value of 7.3 for exterior untreated and treated, this result showed that

neem oil treatment made a significant difference in the reduction of termite infestation for

both interior and exterior environment hence it can be used as a preservative for Atile for both

locations. Rimi had a t-test value of 10.0 for the untreated interior and treated interior samples

while it registered a t-test value of 15.2 for the untreated exterior and treated exterior. This

also showed that neem oil was able to prevent termite infestation of Rimi for both interior and

exterior environments. Doka and Maje untreated and treated samples did not however show

any significant difference in their t-values for both interior and exterior environments. This

implied that susceptibility of Doka and Maje to termite infestation was low and neem oil did

make difference in their preservation but it was not significant.

The F-values of 10.66 and 26.97 on Table 7 showed that all the four wood species had

significant differences in their infestation levels for both untreated interior and exterior

samples. This implied that all the wood species are susceptible to termite infestation but the F-

values of 0.53 and 2.36 for neem oil treated samples across the wood species for interior and

65

exterior environments did not show any significant difference in the levels of termite

infestation for both locations, this could be an indication that the application of neem oil as a

preservative has improved the quality of those wood species that were responsible for the

mean differences of the untreated wood. See details of t-test and one way analysis of variance

(ANOVA) output on appendix V and X respectively.

66

CHAPTER V

SUMMARY, CONCLUSION AND RECOMMENDATIONS

Re-statement of the Problem

The rising demand for timber in Nigeria and Plateau State in particular has forced the

wood industry to resort to the use of lesser known and predominant timbers available in the

locality. Timbers such as Canarium Schweinfurthii (Atile), Ceiba Pentandra (Rimi),

Isoberlina Doka(Doka) and Daniellia Oliveri (Achuwale-Maje) are now being used for

various wood constructions (Keay, 1989). Some of these local timbers however are

susceptible to termite infestations which can lead to deterioration and ultimately much

damage to the structure of wood which result to material wastages, monetary losses and even

loss of lives. Chemical preservatives have been found to be effective in protecting wood

against termites, but their level of toxicity is high and also sources of carcinogenic substances

for humans who apply these chemicals on wood (Mathias and Lorella, 2006). The

environment is also affected through the leaching of these chemicals into plant and aquatic

lives (European Union Commission, 2001). While the United States of America (USA) and

other European Countries have banned the use of these chemical preservatives and have found

alternative preservatives that are expensive and not available to developing countries, Nigeria

is still using these chemical preservatives on wooden structures and articles (European Union

Commission, 2001). There is therefore a need to search for alternative wood preservatives that

are non- toxic to humans and the environment but effective to protect and ensure long service

years of the predominant local timbers being used in Plateau State.

Summary of Procedures Used

The study covered eight local government areas of Plateau State where Neem

(Azadirachta Indica A. Juss) or commonly called “Dogon yaro”, Atile, Rimi, Doka and Maje

64

67

trees are predominant and a termite infested out station in Vom , Jos- South was chosen for

the purpose of the experiment. The purpose of the study was to find out the effect of neem oil

on wood preservation in Plateau State. In specific, the study sought to determine the

following:

The weight loss of termite infested untreated wood

The effect of neem oil on the weight loss of termite infested treated wood

The extent of deterioration of termite infested untreated wood

The effect of neem oil on the extent of deterioration of termite infested treated wood

The extent of termite infestation of untreated wood in exterior and interior

environments

The effect of neem oil on the extent of termite infestation of treated wood in exterior

and interior environments.

To achieve these six purposes, a research and development design was adopted with a true

experimental approach. Ninety-six oven dried samples of 20% moisture content consisting of

24 pieces each from four wood species namely Atile (Canarium Schweinfurthii), Rimi( Ceiba

Pentandra), Doka (Isorberlina Doka) and Maje( Daniellia Oliveri) were prepared in

300x50x25mm lengths.

The 96 wood samples were all weighed using 20kg x50g sensitive weighing scale to

determine the pre-infestation weight of each sample and the data was recorded. Twelve

samples were randomly selected from each of the four wood species and the 96 wood pieces

were divided into two groups of 48 pieces each. One group was categorized as untreated

samples (Control) and the second group as treated samples (experimental). The two groups

were further sub-divided into two groups for exterior and interior samples hence each of the

wood specie had six samples each for interior untreated, interior treated, exterior untreated

and exterior treated. Neem oil was applied on the 48 treatment samples with each sample

68

treated with 25ml of neem oil in two applications ( 24 hours in between coats) using the

brushing method of applying preservatives.

The treated and untreated wood samples were then exposed to field trial test method in

accordance with the American Wood Preservers Association (AWPA) Standards E1-97

(1999) and the Nordic Wood Preservation Council (NWPC) EN 252[2006] Standards in

which samples are exposed to environments and locations that are termite infested and

situations similar to where the wood will be used. The samples were randomly labeled with

the first letter of specie, Ut for untreated or T for treated and a number. All the species were

mapped on a sheet of paper and then exposed to termite infestation for six months between

June and December, a period considered to have high level of termite infestations.

At the end of post- infestation period, samples were recovered following the mapping sheet

from both the exterior and interior environments. They were weighed for post- infestation

weights and rated by three experts in woodwork and building technology using a five point

rating scale adopted from the American Society for Testing and Materials (ASTM) to

determine the levels of deterioration and termite infestation/attack.

Mean and Percentages were used to analyze data for the weight loss of wood while

mean, standard deviation, t-test and one way analysis of variance(ANOVA) were used for

analyzing the extent of wood infestation and deterioration at 0.01 level of significance. The

statistical Package for Social Sciences (SPSS-Version 16) was used for the analysis.

Summary of Findings

The following are the major findings of the study:

1. Untreated Atile and Rimi had very high percentage of weight losses as a result of termite

infestation while Doka and Maje untreated species had slight weight losses.

69

2. Neem oil treated Atile and Rimi wood samples showed low wood weight losses while

Doka and Maje had slight reduction in wood weight loss.

3. Untreated Atile, Rimi, Doka and Maje showed different levels of deterioration due to

termite infestation. Rimi showed the highest level of infestation while Doka was the least

deteriorated of the four wood species.

4. Neem oil treated Atile and Rimi had high reduction in deterioration levels due to termite

infestation while Doka and Maje had only a trace in their deterioration levels with no

significant deterioration.

5. Untreated Atile and Rimi had very high levels of termite infestation in both interior and

exterior environments. All the untreated exterior samples of Rimi were destroyed but Doka

and Maje showed no difference in the levels of infestation for both interior and exterior

environments.

6. Neem oil treated samples for Atile and Rimi were significantly different in termite

infestation from untreated samples for both interior and exterior environments while Doka

and Maje did not show any significant difference between the treated and untreated samples

for both interior and exterior environments.

Implications of Findings

The findings on the very high weight losses of untreated Atile and Rimi and the low

weight losses of Doka and Maje wood species due to termite infestation revealed that Atile

and Rimi are highly susceptible to termite infestations while Doka and Maje are moderately

susceptible to termite infestations. This finding has implication for Woodwork and Building

Technology Teachers and Students who will be guided on selection of more durable Doka and

Maje wood species for practical projects in the workshop over Atile and Rimi. The finding

also brings out the necessity of the use of preservatives on wood by house builders,

70

carpenters, teachers and students. The study further confirms the classification of Atile and

Rimi as softwood while Doka and Maje as hardwood on account of their response to termite

infestation.

On the findings of neem oil treated Atile, Rimi, Doka and Maje wood having low

weight losses is indicative of its potentials as a preservative that industrialists and

entrepreneurs will further refine for wider use. The Society will explore the economic benefit

of raising more neem trees and new market for the seeds and the oil. The environmental safety

of the habitat as a result of using neem oil will ensure good health and well being of the

members of the society.

The findings of the study on the levels of deterioration of untreated Atile, Rimi, Doka and

Maje further confirmed the susceptibility of Atile and Rimi to termite infestation. Builders,

Carpenters, designers, teachers and students will appreciate the need for preservatives to

protect the wood from deterioration.

The Wood Industries will use the findings of the study in obtaining neem oil as a

safer alternative preservative for protecting wood in building construction, furniture and

carpentry work, joinery, for interior and exterior protection of wood items and structures. The

cost of production will also be reduced as wood industries will not rely on imported chemical

preservatives for treating the wood that is used.

Government policy makers both at State and Federal levels will benefit from findings

of the study in enacting policies to stop or regulate the importation of chemical preservatives

thereby saving foreign spending for the country. The programmes of government in checking

the advancement of desert lands in the savannah regions will receive a boost with more neem

trees planted which also has implication for the climate change advocacy in the country. The

71

Ministry of Science and Technology could develop or encourage better and fast ways of

processing neem oil for mass production.

Conclusion

The findings of the study further confirm the claim by wood experts that the non

application of wood preservatives of wood makes it prone to termite infestation and

deterioration.This fact was established in the case of untreated Atile, Rimi, Doka and Maje

wood species which suffered different levels of termite attack as compared to the treated ones

which had significant levels of resistance to termite infestation.The possibility of using neem

oil as a preservative provides a window for its adaptation as an alternative wood preservative

that is safe for human handling and to the environment. The predominant timbers of Atile,

Rimi, Doka and Maje used in Plateau State had their resistance to termite infestation increased

with the application of neem oil therefore it can be inferred that neem oil has the potential of

being an effective wood preservative.

Recommendations

Based on the findings of the study, the following recommendations are made:

1. Neem oil should be brought to limelight by wood related research institutes as a new

innovation that needs to be explored as alternative to the toxic chemical preservatives.

2. Neem oil as an alternative preservative should be included as one of the preservatives

to be studied in Woodwork Technology Courses in Technical Colleges and Industrial

Technical Education Courses in Nigerian Universities; this will increase the frontier of

the search for alternative preservatives for the country.

3. Industrialists and Entrepreneurs should enter into massive production of neem oil to

make it widely available for use by builders and for other varied wood applications.

72

4. Neem trees should be massively planted in Plateau State by Ministry of Agriculture

and Natural resources and the Local Government Forestry Departments in areas

where the climatic conditions are favourable for their growth, this will increase the

motivation for its wider adaptation hence increase the availability of the oil as an

alternative safe preservative.

Limitations

The limitations during the execution of the study were:

1. The state of insecurity within Plateau State was an impediment during the study

because of the constant fear of being attacked by militia men in the location where the

wood samples for the experiment were kept. This had a psychological trauma on the

researcher which almost slowed down the study but was overcome by the researcher.

2. Initial survelliance of wood samples placed in the termite mound against trespassers

was challenging as there were attempts to exhume the samples to see what was buried

in the ground but with vigilance this was averted.

Suggestions for Further Research

The following have been suggested for research:

1. More susceptible wood species should be field trial tested with neem oil

2. Neem oil could be tried to see if it will serve remedial purposes if termite infestation

has set in

3. The effectiveness of neem oil could be tried for various concentrations.

73

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78

APPENDICES

79

Appendix A

Selected Nigerian Timber Species and Their Uses in Building Construction Building Component Recommended Timber Species

Carcassing Afara (Terminalia superba),), Albizia (Albizia spp.),

Alstonia (Alstonia boonei), Celtis (Celtis spp.), n

Dahoma (Piptadeniastrum africanum), Danta

(Nesogordonia papaverifera), Ilomba (Pycnanthus

angolensis), Iroko (Milecia excelsa), Obeche

(Triplochiton scleroxylon)

Door and window frames

(external)

Agba (Gossweilerodendron balsamiferum),

Albizi(Albizia spp.), Apa (Afzelia africana), Danta

(Nesogordonia papaverifera),Gedu Nohor

(Entandrophragma angolense), Iroko (milecia

excelsa), Lagos Mahogany (Khaya ivorensis), Opepe

(Nauclea diderricchii)

Doors and windows – Solid

Afara- white (Terninalia superba), Apa (Afzelia

africana), Black Afara (Terninalia ivorensis), Gedu

Nohor (Entandrophragma angolense), Iroko (milecia

excelsa), Lagos Mahogany (Khaya ivorensis),

Mansonia Mansonia altissima), Sapelewood

(Entandrophragma cylindricum), Utile

(Entandrophragma utile)

Flooring - Decking Agba (Gossweilerodendron balsamiferum),

Albizia (Albizia spp.), Danta (Nesogordonia), Iroko

(milecia excelsa), Omu (Entandrophragma

candolei) (Opepe (Nauclea diderricchii), Sapelewood

(Entandrophragma cylindricum)

Shingles and battens - Abura (Mitragyna stipulosa), Black Afara (Terninalia

ivorensis),Gedu Nohor (Entandrophragma

angolense), Mangrove (Rhizophora racemosa)

Sills and thresholds - Dahoma (Piptadeniastrum africanum), Iroko (milecia

excelsa), Opepe (Nauclea diderricchii)

Stair Treads-

Guarea (Guarea spp.), Mahogany (Khaya spp.),

Sapelewood (Entandrophragma cylindricum)

Roof rafters and purlins Abura (Mitragyna stipulosa), Afara (Terminalia

superba), Agba (Gossweilerodendron balsamiferum),

Albizia (Albizia spp.), Danta (Nesogordonia

papaverifera), Iroko (milecia excelsa), Obeche

(Triplochiton scleroxylon), Opepe (Nauclea

diderricchii), Sapelewood (Entandrophragma

cylindricum)

Source: Lucas, Olurunnisola and Adewole(2006). “Preliminary Evaluation of Guava Tree

Branches Truss Fabrication in Nigeria”. Agricultural Engineering International: the

CIGR Ejournal. Vol. VIII. May, 2006.

80

Appendix B

Termite infested garage doors in Vom, Jos-South Local Government Area of

Plateau State

81

Appendix C

Termite Infested Garage at Vom, Jos South LGA of Plateau State

82

Appendix D

Samples of Materials Collected and Prepared for the Experiment

83

Appendix E

Application of Neem oil on Wood Samples with a 25mm Brush

84

Appendix F

Treated and Untreated Wood Samples in a Termite Mound

85

Appendix G

Post- Termite Infestation Weighing of Wood Samples

86

Appendix H

Wood Samples Deterioration Rating by Three Raters

87

Appendix I

Atile Untreated Post Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Untreated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Atile

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

16

22

27

38

49

51

54

64

65

68

70

75

-

√

-

√

-

√

-

√

-

√

-

√

√

-

√

-

√

-

√

-

√

-

√

-

√

√

√

√

√

√

√

√

√

√

√

√

200

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

20

60

15

75

50

50

50

100

50

50

0

50

180

140

185

125

150

150

150

100

150

150

200

150

90

70

92.5

62.5

75

75

75

50

75

75

100

75

47.5 152.5 76.3

88

Appendix J

Rimi Untreated Post-Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Untreated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Rimi

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

2

5

14

19

21

37

40

50

53

58

69

81

-

-

√

√

√

√

-

√

-

√

-

-

√

√

-

-

-

-

√

-

√

-

√

√

√

√

√

√

√

√

√

√

√

√

√

√

150

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

0

0

40

50

60

15

0

30

0

40

0

0

150

150

110

100

90

135

150

120

150

110

150

150

100

100

73.7

67

60.3

90.5

100

72

100

73.7

100

100

19.4 130.4 86.4

89

Appendix K

Doka Untreated Post Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Untreated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Doka

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

17

28

29

34

36

52

59

63

72

76

79

84

√

-

-

-

√

√

-

-

√

√

√

-

-

√

√

√

-

-

√

√

-

-

-

√

√

√

√

√

√

√

√

√

√

√

√

√

250

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

200

180

175

180

205

200

160

180

190

200

230

190

50

70

75

70

45

50

90

70

60

50

20

60

20

28

30

28

18

20

36

28

24

20

8

24

190.9 59.1 23.6

90

Appendix L

Maje Untreated Post Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Untreated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Maje

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

4

7

26

30

45

47

61

80

83

86

91

96

-

√

-

√

-

-

-

√

√

-

√

√

√

-

√

-

√

√

√

-

-

√

-

-

√

√

√

√

√

√

√

√

√

√

√

√

200

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

100

150

90

160

110

100

130

170

120

80

120

150

100

50

110

40

90

100

70

30

80

120

80

50

50

25

55

20

45

50

35

15

40

60

40

25

123.4 76.6 38.9

91

Appendix M

Atile Treated Post-infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

No.

Interior

environment

Exterior

environment

Treated Pre-

infestation

weight(g)

Post -

infestation

weight (g)

Weight

loss

(g)

Percentage

weight

loss (g)

Atile

“

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

1

10

12

20

35

39

43

48

60

62

71

85

√

-

√

-

√

√

-

-

-

√

√

-

-

√

-

√

-

-

√

√

√

-

-

√

√

√

√

√

√

√

√

√

√

√

√

√

200

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

190

130

150

120

150

140

125

150

150

175

175

140

10

70

50

80

50

50

75

50

50

25

25

60

5

35

25

40

25

30

37.5

25

25

12.5

12.5

30

150.4 49.6 25.2

92

Appendix N

Rimi Treated Post Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Treated Pre-

Infestation

Weight

in (g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Rimi

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

6

15

18

31

33

41

66

67

73

89

92

95

-

√

√

√

-

-

√

√

-

-

-

√

√

-

-

-

√

√

-

-

√

√

√

-

√

√

√

√

√

√

√

√

√

√

√

√

150

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

90

120

100

110

90

95

120

125

85

95

115

95

60

30

50

40

60

55

30

25

65

55

35

55

40

18

33

24

40

36.9

18

15

43.6

36.9

21

36.9

103.3 46.7 30.2

93

Appendix O

Doka Treated Post-Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Treated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Doka

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

3

8

9

13

25

42

44

46

55

77

88

90

√

-

-

-

√

√

√

-

√

-

√

-

-

√

√

√

-

-

-

√

-

√

-

√

√

√

√

√

√

√

√

√

√

√

√

√

250

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

230

200

220

240

230

235

240

225

230

215

240

225

20

50

30

10

20

15

10

25

20

35

10

25

8

20

12

4

8

6

4

10

8

14

4

10

227.5 22.5 9

94

Appendix P

Maje Treated Post Infestation Wood Weight Loss Data for Interior and Exterior

Environments

Wood

Specie

Sample

Number

Interior

Environment

Exterior

Environment

Treated Pre-

Infestation

Weight in

(g)

Post-

Infestation

Weight in

(g)

Wood-

Weight

loss in

(g)

Percentage

Weight

Loss

Maje

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

11

23

24

32

56

57

74

78

82

87

93

94

√

-

-

√

√

-

-

√

√

√

-

-

-

√

√

-

-

√

√

-

-

-

√

√

√

√

√

√

√

√

√

√

√

√

√

√

200

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

„‟

180

170

175

180

190

160

170

180

185

180

170

175

20

30

25

20

10

40

30

20

15

20

30

25

10

15

12.5

10

5

20

15

10

7.5

10

15

12.5

176.5 23.5 11.8

95

Appendix Q

Post Termite Infested Untreated Samples from Interior and Exterior Environments

96

Appendix R

Post- Termite Infested Treated Samples from Interior and Exterior Environments

97

Appendix S

Atile Rimi Doka Maje

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

16

22

27

38

49

51

54

64

65

68

70

75

1.3

7

1.3

7

4

7.6

1.3

6

2.6

2.6

0

2.6

2

5

14

19

21

37

40

50

53

58

69

81

0

0

4

4

4.6

2.6

0

4

0

4

0

0

17

28

29

34

36

52

59

63

72

76

79

84

8

7.6

3.6

7.6

7

6

7.6

7

8

8

9

7

4

7

26

30

45

47

61

80

83

86

91

96

2.6

6

4

7.6

7

7

4

7.6

7.6

7.6

8

9

2.9 1.9 7.2 6.5

Visual Mean Ratings of the Extent of Deterioration of Termite Infested Untreated Wood

Samples.

98

Appendix T

Atile Rimi Doka Maje

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

Sample

Number

Mean

Rating

1

10

12

20

35

39

43

48

60

62

71

85

10

9

7.6

7

7.6

7.6

6

6

7

8.6

10

7

6

15

18

31

33

41

66

67

73

89

92

95

7

9

7.6

8

8

5

8

9

6

6

7

7

3

8

9

13

25

42

44

46

55

77

88

90

8

7

7.6

9.3

10

9.3

8

8.6

10

8

10

7

11

23

24

32

56

57

74

78

82

87

93

94

8.3

9

9

7.6

8

7

7

9

10

10

7

7

7.7 7.3 8.6 8.2

Visual Mean Ratings of the Effect of Neem oil on the Extent of Deterioration of Termite

Infested Treated Wood Samples.

99

Appendix U

RATING SCALE FOR WOOD DETERIORATION

DUE TERMITE ATTACK

INSTRUCTION:

Kindly provide your visual observation by ticking (√ ) in the appropriate box that best

represents the extent of termite attack of the wood samples using the following options of a 5-

point rating scale:

10- Sound timber, no termite attack

9- Trace of termite attack

7- Moderate termite attack

4- Heavy termite attack

0- Destructive termite attack

Sample

Number

10

9

7

4

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

100

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

101

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

102

Appendix V

t-test for Atile

VAR

0000

1 N Mean

Std.

Deviation

Std.

Error

Mean

Initerior Untre

ated 6

5,466

7 2,27918 ,93047

Treat

ed 6

8,566

7 1,17587 ,48005

Exterior Untre

ated 6

1,750

0 1,37514 ,56140

Treat

ed 6

7,000

0 1,09545 ,44721

Levene's Test

for Equality of

Variances t-test for Equality of Means

F Sig. T Df

Sig. (2-

tailed)

Mean

Differ

ence

Std. Error

Difference

95%

Confidence

Interval of

the

Difference

Lower Upper

Initerior Equal

varianc

es

assume

d

4,987 ,050 -2,961 10 ,014

-

3,100

00

1,04701

-

5,432

88

-

,7671

2

103

t-test for Rimi

Group Statistics

VA

R00

001 N Mean

Std.

Devi

ation

Std.

Error

Mean

Inite

rior

Untr

eate

d

6 3,8667 ,6653

3 ,27162

Trea

ted 6 8,1000

,7874

0 ,32146

Exte

rior

Untr

eate

d

6 ,0000 ,0000

0 ,00000

Trea

ted 6 6,5000

1,048

81 ,42817

Equal

varianc

es not

assume

d

-2,961 7,486 ,020

-

3,100

00

1,04701

-

5,543

59

-

,6564

1

Exterior Equal

varianc

es

assume

d

,632 ,445 -7,315 10 ,000

-

5,250

00

,71775

-

6,849

25

-

3,650

75

Equal

varianc

es not

assume

d

-7,315 9,524 ,000

-

5,250

00

,71775

-

6,860

15

-

3,639

85

104

Independent Samples Test

Levene's Test

for Equality of

Variances t-test for Equality of Means

F Sig. T Df

Sig. (2-

tailed)

Mean

Differenc

e

Std.

Error

Differen

ce

95% Confidence

Interval of the

Difference

Lower Upper

Initerior Equal

varian

ces

assum

ed

,455 ,515 -10,059 10 ,000 -4,23333 ,42085

-

5,1710

4

-3,29563

Equal

varian

ces

not

assum

ed

-10,059 9,729 ,000 -4,23333 ,42085

-

5,1745

9

-3,29208

Exterior Equal

varian

ces

assum

ed

15,625 ,003 -15,181 10 ,000 -6,50000 ,42817

-

7,4540

3

-5,54597

Equal

varian

ces

not

assum

ed

-15,181 5,000 ,000 -6,50000 ,42817

-

7,6006

6

-5,39934

105

t-test for Doka

Group Statistics

VAR00001 N Mean Std. Deviation

Std. Error

Mean

Initerior Untreated 6 7,6667 1,03280 ,42164

Treated 6 6,7333 1,56290 ,63805

Exterior Untreated 6 8,4833 1,06286 ,43391

Treated 6 7,9167 ,91305 ,37275

Independent Samples Test

Levene's Test

for Equality of

Variances t-test for Equality of Means

F Sig. t Df

Sig. (2-

tailed)

Mean

Difference

Std. Error

Difference

95% Confidence Interval of the

Difference

Lower Upper

Initerior Equal

varian

ces

assum

ed

,289 ,602 1,220 10 ,250 ,93333 ,76478 -,77070 2,63737

Equal

varian

ces not

assum

ed

1,220 8,667 ,254 ,93333 ,76478 -,80689 2,67356

Exterior Equal

varian

ces

assum

ed

,110 ,747 ,991 10 ,345 ,56667 ,57203 -,70790 1,84124

106

Equal

varian

ces not

assum

ed

,991 9,778 ,346 ,56667 ,57203 -,71184 1,84517

107

t-test for Maje

Group Statistics

VAR00001 N Mean Std. Deviation

Std. Error

Mean

Initerior Untreated 6 7,6333 ,96678 ,39469

Treated 6 8,8333 1,00133 ,40879

Exterior Untreated 6 5,3667 2,08391 ,85075

Treated 6 7,6667 1,03280 ,42164

Independent Samples Test

Levene's Test

for Equality of

Variances t-test for Equality of Means

F Sig. t Df

Sig. (2-

tailed)

Mean

Differenc

e

Std. Error

Difference

95% Confidence

Interval of the

Difference

Lower Upper

Initerior Equal

variances

assumed

,557 ,473 -2,112 10 ,061 -1,20000 ,56823 -2,46610 ,06610

Equal

variances

not

assumed

-2,112 9,988 ,061 -1,20000 ,56823 -2,46631 ,06631

Exterior Equal

variances

assumed

12,50

9 ,005 -2,422 10 ,036 -2,30000 ,94950 -4,41562 -,18438

Equal

variances

not

assumed

-2,422 7,316 ,044 -2,30000 ,94950 -4,52568 -,07432

108

Appendix W

Mean and Standard Deviation of Ratings for Wood Deterioration

N Mean

Std.

Deviation Std. Error

95% Confidence

Interval for Mean

Mini

mum

Maximu

m

Lower Bound

Upper

Bound

Tre

ated

inte

rior

Atile 6 8,5667 1,17587 ,48005 7,3327 9,8007 7,60 10,00

Rimi 6 8,1000 ,78740 ,32146 7,2737 8,9263 7,00 9,00

Doka 6 8,4833 1,06286 ,43391 7,3679 9,5987 7,00 10,00

Maje 6 8,8333 1,00133 ,40879 7,7825 9,8842 7,70 10,00

Total 24 8,4958 ,98532 ,20113 8,0798 8,9119 7,00 10,00

Tre

ated

Ext

erio

r

Atile 6 7,0000 1,09545 ,44721 5,8504 8,1496 6,00 9,00

Rimi 6 6,5000 1,04881 ,42817 5,3993 7,6007 5,00 8,00

Doka 6 7,9167 ,91305 ,37275 6,9585 8,8749 7,00 9,30

Maje 6 7,6667 1,03280 ,42164 6,5828 8,7505 7,00 9,00

Total 24 7,2708 1,11218 ,22702 6,8012 7,7405 5,00 9,30

Unt

reat

ed

Inte

rior

Atile 6 5,4667 2,27918 ,93047 3,0748 7,8585 2,60 7,60

Rimi 6 3,8667 ,66533 ,27162 3,1684 4,5649 2,60 4,60

Doka 6 7,6667 1,03280 ,42164 6,5828 8,7505 6,00 9,00

Maje 6 7,6333 ,96678 ,39469 6,6188 8,6479 6,00 9,00

Total 24 6,1583 2,07761 ,42409 5,2810 7,0356 2,60 9,00

Unt

reat

ed

Ext

erio

r

Atile 6 1,7500 1,37514 ,56140 ,3069 3,1931 ,00 4,00

Rimi 6 ,0000 ,00000 ,00000 ,0000 ,0000 ,00 ,00

Doka 6 6,7333 1,56290 ,63805 5,0932 8,3735 3,60 7,60

Maje 6 5,3667 2,08391 ,85075 3,1797 7,5536 2,60 7,6

Total 24 3,4625 3,08472 ,62967 2,1599 4,7651 ,00 7,60

109

Appendix X

One Way Analysis of Variance(F Ratio) for the Means of Difference of Untreated and Treated

Wood Species

Sum of Squares df Mean Square F Sig.

Treated interior Between Groups 1,655 3 ,552 ,534 ,665

Within Groups 20,675 20 1,034

Total 22,330 23

Treated Exterior Between Groups 7,448 3 2,483 2,364 ,102

Within Groups 21,002 20 1,050

Total 28,450 23

Untreated Interior Between Groups 61,085 3 20,362 10,662 ,000

Within Groups 38,193 20 1,910

Total 99,278 23

Untreated Exterior Between Groups 175,475 3 58,492 26,966 ,000

Within Groups 43,382 20 2,169

Total 218,856 23

110

Appendix Y

Post Hoc Tests

Multiple Comparisons

Dependent

Variable

(I)

Catego

ry

(J)

Cate

gory

Mean

Difference

(I-J)

Std.

Error Sig.

99% Confidence

Interval

Lower

Bound

Upper

Bound

Treated

interior

Scheff

e

Atile Rim

i ,46667 ,58701 ,888 -1,7927 2,7261

Dok

a ,08333 ,58701 ,999 -2,1761 2,3427

Maj

e -,26667 ,58701 ,976 -2,5261 1,9927

Rimi Atil

e -,46667 ,58701 ,888 -2,7261 1,7927

Dok

a -,38333 ,58701 ,933 -2,6427 1,8761

Maj

e -,73333 ,58701 ,673 -2,9927 1,5261

Doka Atil

e -,08333 ,58701 ,999 -2,3427 2,1761

Rim

i ,38333 ,58701 ,933 -1,8761 2,6427

Maj

e -,35000 ,58701 ,948 -2,6094 1,9094

Maje Atil

e ,26667 ,58701 ,976 -1,9927 2,5261

Rim

i ,73333 ,58701 ,673 -1,5261 2,9927

Dok

a ,35000 ,58701 ,948 -1,9094 2,6094

Treated

Exterior

Scheff

e

Atile Rim

i ,50000 ,59163 ,869 -1,7772 2,7772

Dok

a -,91667 ,59163 ,508 -3,1938 1,3605

Maj

e -,66667 ,59163 ,738 -2,9438 1,6105

Rimi Atil

e -,50000 ,59163 ,869 -2,7772 1,7772

Dok

a -1,41667 ,59163 ,160 -3,6938 ,8605

111

Maj

e -1,16667 ,59163 ,303 -3,4438 1,1105

Doka Atil

e ,91667 ,59163 ,508 -1,3605 3,1938

Rim

i 1,41667 ,59163 ,160 -,8605 3,6938

Maj

e ,25000 ,59163 ,980 -2,0272 2,5272

Maje Atil

e ,66667 ,59163 ,738 -1,6105 2,9438

Rim

i 1,16667 ,59163 ,303 -1,1105 3,4438

Dok

a -,25000 ,59163 ,980 -2,5272 2,0272

Untreated

Interior

Scheff

e

Atile Rim

i 1,60000 ,79784 ,289 -1,4709 4,6709

Dok

a -2,20000 ,79784 ,086 -5,2709 ,8709

Maj

e -2,16667 ,79784 ,093 -5,2375 ,9042

Rimi Atil

e -1,60000 ,79784 ,289 -4,6709 1,4709

Dok

a -3,80000

* ,79784 ,001 -6,8709 -,7291

Maj

e -3,76667

* ,79784 ,002 -6,8375 -,6958

Doka Atil

e 2,20000 ,79784 ,086 -,8709 5,2709

Rim

i 3,80000

* ,79784 ,001 ,7291 6,8709

Maj

e ,03333 ,79784 1,000 -3,0375 3,1042

Maje Atil

e 2,16667 ,79784 ,093 -,9042 5,2375

Rim

i 3,76667

* ,79784 ,002 ,6958 6,8375

Dok

a -,03333 ,79784 1,000 -3,1042 3,0375

Untreated

Exterior

Scheff

e

Atile Rim

i 1,75000 ,85031 ,269 -1,5228 5,0228

Dok

a -4,98333

* ,85031 ,000 -8,2562 -1,7105

Maj

e -3,61667

* ,85031 ,004 -6,8895 -,3438

112

Rimi Atil

e -1,75000 ,85031 ,269 -5,0228 1,5228

Dok

a -6,73333* ,85031 ,000

-

10,006

2

-3,4605

Maj

e -5,36667

* ,85031 ,000 -8,6395 -2,0938

Doka Atil

e 4,98333

* ,85031 ,000 1,7105 8,2562

Rim

i 6,73333

* ,85031 ,000 3,4605 10,0062

Maj

e 1,36667 ,85031 ,477 -1,9062 4,6395

Maje Atil

e 3,61667

* ,85031 ,004 ,3438 6,8895

Rim

i 5,36667

* ,85031 ,000 2,0938 8,6395

Dok

a -1,36667 ,85031 ,477 -4,6395 1,9062

*. The mean difference is significant at the

0.01 level.

Homogeneous Subsets

Treated interior

Categor

y N

Subset for

alpha = 0.01

1

Duncana Rimi 6 8,1000

Doka 6 8,4833

Atile 6 8,5667

Maje 6 8,8333

Sig. ,266

Scheffea Rimi 6 8,1000

Doka 6 8,4833

Atile 6 8,5667

Maje 6 8,8333

Sig. ,673

Means for groups in homogeneous subsets are

displayed.

a. Uses Harmonic Mean Sample Size = 6,000.

113

Treated Exterior

Categor

y N

Subset for

alpha = 0.01

1

Duncana Rimi 6 6,5000

Atile 6 7,0000

Maje 6 7,6667

Doka 6 7,9167

Sig. ,038

Scheffea Rimi 6 6,5000

Atile 6 7,0000

Maje 6 7,6667

Doka 6 7,9167

Sig. ,160

Means for groups in homogeneous subsets are

displayed.

a. Uses Harmonic Mean Sample Size = 6,000.

Untreated Interior

Catego

ry N

Subset for alpha = 0.01

1 2

Duncana Rimi 6 3,8667

Atile 6 5,4667 5,4667

Maje 6 7,6333

Doka 6 7,6667

Sig. ,059 ,016

Scheffea Rimi 6 3,8667

Atile 6 5,4667 5,4667

Maje 6 7,6333

Doka 6 7,6667

Sig. ,289 ,086

Means for groups in homogeneous subsets are

displayed.

a. Uses Harmonic Mean Sample Size = 6,000.

114

Untreated Exterior

Catego

ry N

Subset for alpha = 0.01

1 2

Duncana Rimi 6 ,0000

Atile 6 1,7500

Maje 6 5,3667

Doka 6 6,7333

Sig. ,053 ,124

Scheffea Rimi 6 ,0000

Atile 6 1,7500

Maje 6 5,3667

Doka 6 6,7333

Sig. ,269 ,477

Means for groups in homogeneous subsets are

displayed.

a. Uses Harmonic Mean Sample Size = 6,000.