biodiesel report - literature review for 20 potentially viable plant species to be used as a...
DESCRIPTION
For any plant to be considered as a viable candidate for use as a biodiesel fuel source, several standards must be met. The ecology of which the perspective plant can thrive is the first and most important aspect. The ecology of a plant dictates where the plant can actually be cultivated, imposing certain limits on its viability. If applicable areas available for cultivation are limited or occupy land necessary for other important crops, such as food crops, the plant cannot be considered as an applicable candidate. Thus, to be suitable, a plant must have wide dispersal ability, whether that be by having a tolerance to a range of environments and soil types or matching the ecology of available or desired areas. Secondly, cultivation requirements are a key aspect. The extent of irrigation or drainage systems, weeding, fertilising, trimming or pruning, planting, growth rates, propagation, and watering needs, have a major effect on large scale production. In particular, the ability to harvest and collect the fruits and the difficulty to extract either the seeds or kernels has a major effect on the viability of the plant.TRANSCRIPT
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LITERATURE REVIEW FOR 20
POTENTIALLY VIABLE PLANT SPECIES TO
BE USED AS A BIO-DIESEL FEEDSTOCK
Luke Asgill & Erond Perez
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Table of Contents
List of Figures ................................................................................................................................................. i
List of Tables ................................................................................................................................................. ii
1. Introduction .......................................................................................................................................... 1
2. Current Biodiesel Fuel Production & Use ............................................................................................. 2
3. Potentially Viable Plant Species to be used as Biodiesel Feed-Stocks .................................................. 4
3.1 Calophyllum Inophyllum (Beauty Leaf) ............................................................................................... 5
3.2 Aleurites Moluccana (Candle Nut Tree) .............................................................................................. 7
3.3 Syagrus Romanzoffiana (Queen Palm) ................................................................................................ 9
3.4 Murraya Exotica (Mock Orange) ....................................................................................................... 11
3.5 Cordyline Manners-Suttoniae (Cordyline) ........................................................................................ 13
3.6 Grevillea Banksii (Grevillea) .............................................................................................................. 15
3.7 Elaeocarpus Grandis (Blue Quandong) ............................................................................................. 17
3.8 Ochna Serrulata (Ochna) ................................................................................................................... 19
3.9 Brachychiton Bidwilli ......................................................................................................................... 21
3.10 Koelreuteria Formosana (Chinese Rain Tree) .................................................................................. 23
3.11 Santalum Album (Sandalwood) ...................................................................................................... 25
3.12 Argemone Mexicana (Mexican poppy) ........................................................................................... 27
3.13 Petalostigma Pubescens (Quinine bush) ......................................................................................... 29
3.14 Brachychiton Acerifolius (Flame Tree) ............................................................................................ 31
3.15 Jagera Pseudorhus (Jagera) ............................................................................................................ 33
3.16 Ricinus Communis (Castor Oil Seed) ............................................................................................... 35
3.17 Atalaya Hemiglauca (Whitewood) .................................................................................................. 37
3.18 Dianella Caerulea (Blue Berry Lily) .................................................................................................. 39
3.19 Pongamia Pinnata (Karanja) ........................................................................................................... 41
3.20 Cocos Nucifera (Coconut Palm) ....................................................................................................... 43
4. Discussion & Evaluation of the Viability for use as a Biodiesel Feed-Stock ........................................ 45
4.1 Harvesting & Potential Yield Analysis: .......................................................................................... 45
4.2 Cultivation Analysis: ...................................................................................................................... 48
4.3 Plant Analysis Summary: ............................................................................................................... 49
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4.4 Comparative Analysis: ................................................................................................................... 50
5. Conclusions & Recommendations ...................................................................................................... 52
6. References (Prepared using Mendeley Desktop) ................................................................................ 53
Appendices .................................................................................................................................................. 57
Appendix i Primary Information Regarding Cultivation and Yields of the Native or Naturalised Plant
Species .................................................................................................................................................... 57
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List of Figures
Figure 1 - Calophyllum Inophyllum growing along a beach front, and in a park and its distribution in
Australia. ....................................................................................................................................................... 5
Figure 2 - The fruit & kernels of Calophyllum Inophyllum. ........................................................................... 6
Figure 3 - The Aleurites Moluccana tree, its dispersion throughout Australia and the kernels that it
produces. ...................................................................................................................................................... 7
Figure 4 - The Syagrus Romanzoffian tree, an inflorescence of the fruit produced, and its current and
potential distribution. ................................................................................................................................... 9
Figure 5 - Seeds of a Syagrus Romanzoffiana tree. .................................................................................... 10
Figure 6 - The Murraya Exotica's current and potential distribution in Australia, a full grown shrub, and
the fruit produced. ...................................................................................................................................... 11
Figure 7 - Seed produced from the fruit of a Murraya Exotica tree. .......................................................... 12
Figure 8 - The distribution of Cordyline Manners-Suttoniae, the panicles of fruit produced and a fully
grown tree................................................................................................................................................... 13
Figure 9 - The seeds removed from a fruit of the Cordyline Manners-Suttoniae tree. .............................. 14
Figure 10 - The fruit and distribution of Grevillea Banksii in Australia. ...................................................... 15
Figure 11 - Seeds taken from a Grevillea Banksii plant............................................................................... 16
Figure 12 - The racemes of flowers bloomed from Elaocarpus Grandis. On the right, a full grown tree and
the current and potential distributions on the bottom left. ...................................................................... 17
Figure 13 - Fruit and kernel of Elaeocarpus Grandis. .................................................................................. 18
Figure 14 - The Ochna Serrulata shrub, with its yellow flowers and the fruits produced. In the bottom
right, is the distribution of the shrub in Australia. ...................................................................................... 19
Figure 15 - Seeds produced by an Ochna Serrulata shrub. ......................................................................... 20
Figure 16 - Brachychiton Bidwilli, its current distribution and its potential distribution in Australia. ....... 21
Figure 17 - The dried fruit and seeds within of a Brachychiton Bidwilli shrub/tree. .................................. 22
Figure 18 - The current and potential distribution of Koelreuteria Formosana, the fruit it bears and a full
grown tree................................................................................................................................................... 23
Figure 19 - Seeds extracted from the fruit of a Koelreuteria Formosana tree. .......................................... 24
Figure 20 - The Santalum Album (or Sandalwood) tree, its current distribution in Australia and the small
clusters of fruit produced. .......................................................................................................................... 25
Figure 21 - The dried fruit and seeds contained from Santalum Album. ................................................... 26
Figure 22 - The current and potential distribution of the Mexican poppy and a fully grown shrub. ......... 27
Figure 23 - The fruit produced by an Argemone Mexicana plant and the seeds contained. ..................... 28
Figure 24 - A full grown shrub with matured fruits and the current distribution of Petalostigma
Pubescens. ................................................................................................................................................... 29
Figure 25 - Peeled back dry skin of a fruit from a Petalostigma Pubescens plant, reveealing the endocarp.
.................................................................................................................................................................... 30
Figure 26 - The current distribution of Brachychiton Acerifolius in Autralia, a fully blooming tree and the
large fruits produced................................................................................................................................... 31
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Figure 27 - Seeds extracted from a fruit of the Brachychiton Acerifolius. .................................................. 32
Figure 28 - Jagera Pseudorhus, its fruits and the current distribution within Australia. ............................ 33
Figure 29 - Seeds produced by Jagera Pseudorhus..................................................................................... 34
Figure 30 - Ricinus Communis, the seeds produced and its current and potential distribution through
Australia. ..................................................................................................................................................... 35
Figure 31 - Seeds produced by Ricinus Communis. ..................................................................................... 36
Figure 32 - The current distribution of Atalaya Hemiglauca, a full grown tree and the fruits yielded. ..... 37
Figure 33 Fruits produced by Atalaya Hemiglauca. ................................................................................. 38
Figure 34 - Dianella Caerulea, its flowers and a distribution map for New South Wales........................... 39
Figure 35 - Seeds produced by Dianella Caerulea. ..................................................................................... 40
Figure 36 - Pongamia Pinnata, a cluster of the pod fruits and a map of the trees current distribution. ... 41
Figure 37 - Seeds produced by Pongamia Pinnata. .................................................................................... 42
Figure 38 - Full grow Cocos Nucifera trees, the bunches of fruit produced and the current distribution in
Australia. ..................................................................................................................................................... 43
Figure 39 - A cracked open coconut revealing the white copra within. ..................................................... 44
Figure 40 - Graphical Representation of the Oil and Seed or Kernel Yields. .............................................. 46
Figure 41 - A comparison of the oil content by mass. ................................................................................ 47
List of Tables
Table 1 - Basic information covering the cultivation and yields of two currently emplyed biodisel feed-
stocks [4750]. ............................................................................................................................................ 51
Table 2 - Summarised, tabular representation of the key information presented in Section 3. ................ 58
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1. Introduction
Transportation has always been a critical aspect of society granting longer, faster and more effective
travel, in turn allowing trade to flourish. The diesel engine, one of the primary devices utilised for travel
in modern society, was firstly integrated into society after petroleum mining and oil refining techniques
developed. Petroleum based diesel (or petrodiesel) has long since been the fuel of choice for not just the
diesel engine, but in many cases, for transportation as a whole. Petroleum mining and the production of
diesel fuel from petroleum were and still are a more cost-beneficial alternative to the biodiesels originally
used. It is due to its wide spread use and cost superiority that petroleum based diesel, as well as other
products derived from petroleum, have become established as a major constituent of the global economy.
However, since industrialising, concerns around petrodiesel and its use continue to grow.
In 1993, legislative action was put in place to reduce on road diesel fuel sulphur levels to 500 ppm. The
primary reason for this stems from the amount of particulate matter produced from exhaust pipes due to
the oxidisation of sulphur particles within the combustion chamber. This particulate matter had an evident
effect on human health. Aside from such direct health effects, there is the constant concern over peak oil.
Though peak oil speculations are difficult to make, it is inadvertently clear that demand for petroleum
based products continues to grow while the known supply continues to diminish. Furthermore, with an
increasing demand and a fluctuating supply, costs for petrodiesel continue to increase which can impose
significant strains on the global economy, particularly in the mining and transportation sectors. Even more
prominent recently, has been the climate change issues. Concerns for the global climate, or more heavily
on local climates, due to rising average temperatures have put pressure on the petroleum based diesel
industry. Diesel powered engines produce more polluting emissions than alternative technologies, such
as gasoline, electric or fuel-cell powered engines.
It is because of the recent climate concerns that alternative energy sources and technologies to currently
employed ones are being sought after. Organically based diesel fuels (or biodiesels), such as those derived
from plant matter, are one such alternative. Biodiesel fuels are produced from renewable sources
negating concerns over peak oil and thus limiting potential pressure on the economy. Also, the most
publicly apparent harmful emission to the environment is carbon dioxide and as biodiesels are generated
and burnt on a closed carbon cycle (just as much or less CO2 is produced when burning biodiesels as the
plants they are derived from consume), the use of such fuels helps appease concerns over local and global
climates. In addition, the use of biodiesel fuels does not need a reform or change of current infrastructure
and technologies, unlike electric, solar or fuel cell powered vehicles. This is particularly so for domestic
environments.
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2. Current Biodiesel Fuel Production & Use
The idea of using biofuels in an internal combustion engine dates back to
1929 when Rudolph Diesel first fired his newly invented diesel engine with raw
vegetable (peanut) oil. However, Diesel and others discovered that fuelling a diesel
engine with vegetable oils could reduce atomization, lower heating value and
worsen combustion and cause other long-term problems including pump wear and
carbon/coke deposits.
In recent years, biofuels producers have achieved significant improvements in
crop production and processing efficiencies and today the volume of biofuels
produced in a specific planted area is several times higher than it used to be.
Improved production methods and technologies are expected to increase
efficiencies even further.
One of the main goals of developing the biofuels sector is sustainability. The
sustainability driver is based on the three pillars of economic, social and
environmental sustainability. In economic terms, biofuels production has to be cost-
effective and competitive. In social terms, biofuels development can create a
massive new demand in the agricultural economy. As biofuels production is an
agricultural process, the same elements and inputs contribute to its overall
efficiency as for existing agricultural production systems. [1]
Biofuel production is ever increasing. According to the latest official statistics, global production of
biofuels reached over 34 million tons (Mtoe) of oil in 2007 which accounts for 1.5% of total road related
fuel consumption. By 2015, biofuel production is projected to reach 60 Mtoe and over 90 Mtoe by 2030.
Currently, Brazil and USA are the leaders in biofuel production in which both countries produce mainly
bioethanol [1].
Production of biofuel is a global trend and many other countries also support and participate in
production. Israel focuses on non-edible feedstock such as Jatropha, Castor, cellulosic biomass and algae
for production and aims to process 4-5% of the global biofuel market by 2012. In China, the government
made E10 blends mandatory in five provinces which accounts for 16% of the nations passenger cars.
Thailand mandated a 10% ethanol mix in gasoline, in 2007. Due to this, the palm oil industry now has
plans to supply an increasing portion of national diesel fuel requirements for both Malaysia and Indonesia.
In Canada, government made plans for 45% of the countrys gasoline consumption to contain 10% ethanol
by 2010. India has made goals to reduce its dependence on coal and petroleum to meet its increasing
energy demand; partly by encouraging Jatropha cultivation, which is one of the crucial components of
Indias energy policy. The Indian government is hoping Jatropha biodiesel will replace 20% of its diesel
consumption by 2011 [2]. Finally, in Australia, the government aimed to increase its ethanol and biodiesel
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consumption to 350 mega litres by 2010 by actively encouraging users of government vehicles to purchase
E10 and allowing E5 blends to be sold unlabelled, subject to the results of vehicle testing. Furthermore,
REDI awarded a funding of 5 million AUD for development of high-yield sugarcane for bioethanol
production [3].
Though biofuel production and use has many advantages, there are also a number of drawbacks. For one,
it could impede upon land use for food and other crops since the feed-stocks could also enter the animal
or human food chain. This has caused much controversy over biofuel production, as it is criticized for the
potential to cause food shortages and price rises. There is also the concern over capital costs as most
biofuel production processes cannot supply more than a few per cent of energy requirements sustainably,
while potential biofuel processes that can supply more energy and result in better environmental gains,
have establishing costs of around 750 million AUD. To add to this, there are issues concerned with fuel
properties such as the corrosiveness of ethanol, increase in fuel consumption, pre-ignition knocking, the
need for engine modification, and its modest net energy gain. Lastly, the stability of biofuels; as biodiesel
is chemically an ester molecule, there is every possibility that in the presence of air or oxygen, it will be
hydrolysed to alcohol and acid which causes reduction in flash point and increase in total acid number
along with a number of other undesirable property changes. Consequently, all these make methyl ester
fuels relatively unstable in storage and cause damage to various engine components [2].
Energy efficiency and energy balance of biofuels must be considered as well. Production of biofuels from
raw materials requires energy for farming, transport, a conversion process to achieve the final product,
production or application of fertilizers, pesticides, herbicides and fungicides, all of which also have
environmental consequences. The energy balance of a biofuel is determined by the amount of energy
consumed during the production of the fuel compared to the amount of energy released when it is used
[2].
Though there are a number of potential drawbacks to using biodiesel fuels, most of these relate to
chemical or tribological properties of the fuels produced from the organic sources. This paper focuses on
cultivation requirements and potential oil yields of the organic sources themselves. The potential of
twenty native or naturalised Australian plant species will be examined for their ability to be grown in great
abundance, without impeding upon important crops and their potential yearly oil yields. The purpose of
this paper is to identify a number of plant species viable for use as biodiesel feed-stocks and thus, to serve
as a basis for further research into the fuel quality of viable biodiesel fuel sources.
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3. Potentially Viable Plant Species to be used as Biodiesel Feed-Stocks
For any plant to be considered as a viable candidate for use as a biodiesel fuel source, several standards
must be met. The ecology of which the perspective plant can thrive is the first and most important aspect.
The ecology of a plant dictates where the plant can actually be cultivated, imposing certain limits on its
viability. If applicable areas available for cultivation are limited or occupy land necessary for other
important crops, such as food crops, the plant cannot be considered as an applicable candidate. Thus, to
be suitable, a plant must have wide dispersal ability, whether that be by having a tolerance to a range of
environments and soil types or matching the ecology of available or desired areas. Secondly, cultivation
requirements are a key aspect. The extent of irrigation or drainage systems, weeding, fertilising, trimming
or pruning, planting, growth rates, propagation, and watering needs, have a major effect on large scale
production. In particular, the ability to harvest and collect the fruits and the difficulty to extract either the
seeds or kernels has a major effect on the viability of the plant.
Aside from environmental and cultivation requirements, the potential yields per hectare must also be
considered. This is affected by the number of harvests possible per year, the amount of seeds or kernels
attained per harvest and finally, the oil content of the seeds or kernels. A final consideration that must be
taken into account is the economic necessities revolving around the production of oil from the plants. The
primary costs incorporate the costs of cultivation, which depend on the factors aforementioned and the
costs of oil extraction from collected seeds or kernels. The following pages discuss the ecology and
cultivation requirements of twenty native or naturalised Australian plants that possess potential to be
viable sources of biodiesel fuel.
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3.1 Calophyllum Inophyllum (Beauty Leaf)
Calophyllum Inophyllum, or more commonly known as Beauty Leaf, is a moderately sized tree ranging
between 8-20 m tall that is most notable for its decorative leaves and fragrant flowers, as can be seen in
Figure 1 below [4][5]. The tree grows in tropical and sub-tropical climates (typical temperature range of
18-33 oC) close to sea level. In Australia, Beauty Leaf trees grow in free draining soils near shorelines;
however, it has been seen to grow in various different clay soils both within Australia and various parts of
southern and more central Asia such as Sri Lanka and India [4][5]. Figure 1 below, illustrates the areas in
which Calophyllum Inophyllum has been identified to grow naturally throughout Australia [6]. The areas
seen in Figure 1 all have annual rainfalls that meet the 1000-5000 mm requirement for Calophyllum
Inophyllum to flourish [7]. In most of these areas, the plant grows along hard clay slopes cascading down
to a beach front [4].
Figure 1 - Calophyllum Inophyllum growing along a beach front, and in a park and its distribution in Australia.
The Beauty Leaf tree bears fruits twice a year, the time of which depends upon when the tree was planted
as it is an evergreen. With two yields per year, a healthy tree produces around 8000 fruits, each of which,
contain a kernel within a hard husk [5][6][7]. Both the fruit and kernels produced by the Beauty Leaf tree
can be seen in Figure 2 on the ensuing page.
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Figure 2 - The fruit & kernels of Calophyllum Inophyllum.
Cultivation of Calophyllum Inophyllum:
Calophyllum Inophyllum can be transplanted from nurseries very successfully; although, for the purpose
cultivation, it is more beneficial to grow the trees from direct seeding. The Beauty Leaf tree is a moderately
quick growing tree that can grow up to 1 m tall within a year. It has also been seen to flourish even with
the presence of weeds and other species, so the plant can be grown in mixed cultures and weeding is not
necessary [4][7].
As mentioned, Calophyllum Inophyllum has the ability to grow in a range of clay soils as well as sand, thus
genotypes can be grafted to meet soil types of various locations. Furthermore, this tree can withstand
soils holding a medium to low fertility, although it can only cope with low levels of salinity [5][7]. The
watering requirement is between 1000-5000 mm per year, which is best dispersed throughout the year
to attain the highest yields and maintain the health of the trees.
The fruits are harvested either directly from the tree once they have fully matured or once they have
fallen off [7]. As a number of animals have been noted to eat the fruit, it is safe practice to harvest the
fruits from trees just before they fully mature. The kernels themselves are contained in a hard shell, as
seen from Figure 2 above. These shells must be dried thoroughly so that they can be broken and the
kernels extracted [6][7].
The kernels extracted from the fruit have a dry weight of about 5 g, which, with around 4000 fruits per
harvest (or 8000 per year, as fruits are produced twice a year), results in around 40 kg of kernels, per tree,
per year [5][6]. The spacing of the trees should be 5x5 m, allowing 400 trees per hectare. With 400 trees
per hectare a total of 16000 kg of kernels can be produced per year [6][7]. These kernels contain about
46% useful oil on a unit mass basis, which means each tree can yield approximately 18.4 kg of oil, thus
resulting in about 7360 kg of oil per year, per hectare [6].
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3.2 Aleurites Moluccana (Candle Nut Tree)
The tree seen in Figure 3 below is the Aleurites Moluccana, which has come to be known as the Candle
Nut tree for the traditional use of its waxy seeds and kernels as natural candles. Aleurites Moluccana
grows naturally in both subtropical and tropical dry or wet forest climates, reaching altitudes of up to 700
m [6][8]. In order to flourish, this tree requires an annual rainfall of 640-4300 mm and prefers light or
medium textured soils such as basalt, red loams, sand, limestone, and stone clay [9]. Also seen in Figure
3 below, is the dispersion of the Candle Nut tree in Australia [6]. The Aleurites Moluccana begins bearing
fruit after about 3-4 years of age. The fruits are typically 5-8 cm in diameter and contain two seeds. The
fruits are usually fully mature and begin dropping off the tree between March and May [8][9].
Figure 3 - The Aleurites Moluccana tree, its dispersion throughout Australia and the kernels that it produces.
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Cultivation of Aleurites Moluccana:
Aleurites Moluccana is a moderately fast growing tree reaching up to 1.5 m growth each year and attaining
a maximum height of 10-15 m [8][9]. It is best planted at the beginning of the rainy season from 3-4 month
old nursery raised seedlings. Being nursery raised, the seeds undergo a sowing treatment which hastens
the germination process [9]. It is crucial that lands are cleared of weeds before transplanting the young
trees for cultivation. The trees should also be spaced in 7x7 m blocks for the purposes of oil cropping; this
results in just over 200 plants per hectare [9].
The Aleurites Moluccana tree requires little to no irrigation, it does however, require extensive weeding
during its first year of growth. For every year after the first, until it is fully grown, weeding should be
continued 2-4 times a year [9]. Upon fully maturing, the tree requires little to no maintenance depending
on the aggressiveness of weeds. In regards to its watering requirements, the tree needs 640-4300 mm of
annual rainfall [8][9].
With good conditions, around 7000 fruits can be yielded by any one tree. This totals to 14000 seeds and
thus kernels per tree, per year [9]. The fruits can be collected from the ground around the trees after they
have fully matured and dropped off [9]. Tarps can be utilised by placing them on the floor around the
trees, stopping them from being hidden amongst surrounding foliage. The kernels are extracted by
cracking the hard shells of the seeds once fully dried.
The kernels have a dry weight of about 6 g, which, on a per hectare basis, yields around 16800 kg of dried
kernels per year [9]. As the kernels produced by the Candle Nut tree contains approximately 47% oil on a
unit mass basis, a total of 7900 kg of oil can be produced per year, per hectare [6]. It should be noted that
the oil extracted from candlenuts possess high levels of linoleic acid which presents issues with its use as
a biodiesel fuel [6].
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3.3 Syagrus Romanzoffiana (Queen Palm)
Syagrus Romanzoffiana, the Queen Palm has been declared as a weed by the Australian Government for
its rapid propagation through south-east Queensland [10]. The tree, seen in Figure 4 below, is a tall slender
palm reaching heights around 20 m. It is tolerant towards a number of rainforest conditions such as,
subtropical, tropical, and wetlands. It generally grows near rivers, lakes and other sources of water,
particularly along coastal regions [10][11]. Syagrus Romanzoffiana grows on a range of soil types from
sand to heavy cracking clays and can survive in a wide range of temperatures (from sub-zero temperatures
to low 40s) [10].
Figure 4 - The Syagrus Romanzoffian tree, an inflorescence of the fruit produced, and its current and potential distribution.
The Queen Palms rapid dispersion is attributed to its rapid growth, the large number of fruits and seeds
produced, and the tendency of a number of bird species to collect and spread the seeds. The Queen Palm
can bear fruits throughout the year depending on the conditions. The fruits grow in an inflorescence off
panicles that can grow up to 2 m long [10][11]. The number of fruits contained on any inflorescence ranges
greatly from tree to tree [11]. Although the current distribution of Syagrus Romanzoffiana is limited to
south-east Queensland and north-east New South Wales, the figure above illustrates the potential
distribution of the tree which covers the entire coast of Queensland and a large section of the Northern
Territory [10].
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Cultivation of Syagrus Romanzoffiana:
This plant is most suited for acidic, well-drained soils, thus drainage systems are a necessary requirement
for large scale cultivation [11]. However, as illustrated in Figure 4 above, this tree has substantial
propagation abilities, partly due to its adaptability to a large range of soil types, tolerance to a range of
temperatures, and moderately low watering requirements of 400-2000 mm per year [10][11].
Syagrus Romanzoffiana grows best in full sunlight and is tolerant to mild salinity, but suffers severe
mineral deficiencies on alkaline soils. This tree can quickly deteriorate without proper maintenance, such
as consistent watering throughout the year and maintaining the soil quality [11]. The tree, as mentioned
previously, has a rapid growth rate and responds well to ample moisture and plenty of sunlight. It should
be spaced by 5x5 m, allowing 400 trees per hectare [6][11].
With proper conditions and maintenance, especially watering, sunlight, and soil conditions, around 2000
kg of fruit can be produced per hectare per year, assuming two harvests a year [6]. The fruits can be
collected by cutting the panicles that they grow off from the tree or by collecting them from the floor
once they have fully matured. The fruits are about 2.5-3 cm long and have a diameter of 1-2 cm and
contain a stringy or hairy kernel, seen below [11].
Figure 5 - Seeds of a Syagrus Romanzoffiana tree.
The kernels contained within are extracted by allowing the fruit to ferment, peeling away the soft flesh,
then letting the kernel and husk dry. Once fully dry, the husks surrounding the kernels are easily removed.
Alternatively, the entire seed can be crushed and oil extracted from the resulting mixture of kernel and
husk. This method, although easier, is not as desirable as the husks tend to soak up some of the oil [6][11].
The kernels obtained from Syagrus Romanzoffiana, contain between 41 and 47% oil on a unit mass basis.
Thus, with approximately 2000 kg of kernels per year, per hectare around 820-940 kg of oil can be
produced [6]. This value can vary quite greatly depending on the conditions in which the tree is grown,
the number of harvests made per year, and the method of harvesting.
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3.4 Murraya Exotica (Mock Orange)
Originating from southern and central Asia, Murraya Exotica is a shrub distinguished by its ornate, white
flowers and citrus smelling leaves [12]. The evergreen shrub grows at elevations up to 1300 m on well
drained soils comprised from sedimentary or igneous rocks, such as limestone. It usually grows to a height
of 2-3 m but can grow into a small tree of, at most, 12 m [12]. This shrubs large dispersal throughout
Australia is due to the propagation of its seeds by birds, and can be seen in Figure 6 below. Also seen in
the figure below is the ripened fruit which has a distinctive red colour. Although Murraya Exotica flowers
irregularly throughout the year, the main flowering period is during late spring and early autumn [12]. The
fruits reach a size of about 0.8-2 cm long and contain one or two hairy seeds which have a dry weight of
about 0.06 g [6].
Murraya Exotica is a resilient shrub that can withstand temperatures down to -4 oC and survive through
extended periods of drought. Its annual rainfall requirement is 750-1900 mm [12].
Figure 6 - The Murraya Exotica's current and potential distribution in Australia, a full grown shrub, and the fruit produced.
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Cultivation of Murraya Exotica:
The shrub is grown from direct seeding (transplanting from nurseries is not recommended, especially for
cultivation for oil cropping) and grows at a moderate pace. The shrub however, does not cope well in
mixed cultures and thus weeding is a necessity during its growth [6][12]. Murraya Exotica grows best in
partial shade on limestone.
As seen on the preceding page, this plant has a very large dispersion, growing with low annual rainfalls of
750-1900 mm and on a range of well drained soils. This plant has further potential to be cultivated all
through eastern and central Queensland and the northern sections of Western Australia and Northern
Territory.
The shrubs should be spaced 2x2 m allowing 2500 plants per hectare. A healthy shrub can produce around
2500 fruits or 5000 seeds in a year. The seeds are small, as seen in Figure 7 below, and have a weight of
0.06 g, yielding 750 kg of seeds per hectare, per year [6]. The dried seeds have an oil content of about
22%, which yields a total of 165 kg of oil per hectare, per year [6].
Figure 7 - Seed produced from the fruit of a Murraya Exotica tree.
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3.5 Cordyline Manners-Suttoniae (Cordyline)
Commonly referred to as simply Cordyline, the Cordyline Manners-Suttoniae is a small tree that somewhat
resembles palm trees. It is an evergreen tree that typically grows in rainforests, but has also been seen in
various other forest climates [13]. The tree grows near swamps or other areas with poorly drained soils.
The tree usually grows to about 2-3 m tall, but sometimes reaches up to 5 m [13].
Figure 8 - The distribution of Cordyline Manners-Suttoniae, the panicles of fruit produced and a fully grown tree.
The figure above illustrates the panicles of fruit which can be produced throughout the year. These
panicles reach lengths of about 25 cm and the fruits have a diameter of around 1-1.5 cm [13]. Also seen
in Figure 8 is the current distribution of the Cordyline tree within Australia [6].
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Cultivation of Cordyline Manners-Suttoniae:
This small tree grows best in well shaded areas with a plentiful supply of water. It is easily identifiable
when this tree does not have sufficient shading as the leaves quickly scorch under direct sunlight. The tree
can however, withstand dry conditions so long as irrigation systems are utilised appropriately [13].
Cordylines continue to flourish in the presence of other species and so can be grown in mixed species as
an understory plant [13]. Each tree takes up a very small amount of space allowing for a total of around
10000 trees per hectare [6]. The fruits can be collected by picking them directly from the tree by cutting
off the panicles that they grow on and the seeds, as seen in Figure 9 below, can be extracted with relative
ease as the fruits are fairly soft.
Figure 9 - The seeds removed from a fruit of the Cordyline Manners-Suttoniae tree.
On a per hectare basis, around 3000 kg of seeds can be produced by Cordylines. The seeds have an oil
content, per unit mass, of about 12% [6]. Considering this plant can bloom numerous times throughout
the year, if three harvests are made per year, a total of 360 kg of oil can be produced per year, per hectare.
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3.6 Grevillea Banksii (Grevillea)
Grevillea Banksii is a resilient, evergreen shrub that typically grows in sub-tropical climates. The shrub is
moderately sized and can survive with minimal rainfall. The shrub grows on free draining soils and features
characteristic red tooth brush like panicles, as illustrated in the figure below. These flowers can bloom
throughout the year and can often grow into small trees possessing a number of primary stems [14].
As seen in Figure 10, the Grevillea has been naturalised in central, eastern Queensland. With its resilience
towards marginal rainfalls, the shrub can be expected to continue to propagate through south-east
Queensland and towards the drier, central regions of Queensland.
Figure 10 - The fruit and distribution of Grevillea Banksii in Australia.
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Cultivation of Grevillea Banksii:
This shrub grows best in light, gritty free-draining soils in areas with plentiful sunlight. The soil should also
possess low levels of phosphates [14]. Furthermore, although this plant may be drought tolerant, in order
to maintain consistent and profitable yields for cropping, deep watering systems should be employed [14].
This plant is grown with the greatest success from trimmed, nursery raised plants. Grevillea can however,
be grown fairly successfully when grown directly from seeding [14]. The seeds seen below are removed
from their fruits which are collected by trimming the brush like panicles once fully matured.
Figure 11 - Seeds taken from a Grevillea Banksii plant.
A total of about 2500 shrubs can be grown in a hectare of land. As this shrub blooms throughout the year,
several harvests can be made on a yearly basis. Per harvest, a Grevillea shrub can yield about 0.5 kg of
seeds, if two harvests are made per year. Thus, per hectare, 2500 kg of seeds can be produced from
Grevillea Banksii shrubs. These seeds contain approximately 15% oil on a unit mass basis, which yields 375
kg of oil per year, per hectare [6].
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3.7 Elaeocarpus Grandis (Blue Quandong)
With characteristic bell shaped flowers and bright blue fruits, the Elaeocarpus Grandis is a large tree that
grows in sub-tropical rainforests conditions near moist, scrubby water courses. This tree grows at
elevations up to 800 m, with a temperature range of 5 to 35 oC [15][16]. The current and potential
dispersal of Elaeocarpus Grandis is displayed in Figure 12 below. As seen, the areas that this tree currently
grows are within sub-tropical and tropical parts of Queensland. With similar conditions all along the coast
of Queensland and Northern Territory, as well as the northern end of Western Australia, this tree has the
potential to be grown in a large area.
Figure 12 - The racemes of flowers bloomed from Elaocarpus Grandis. On the right, a full grown tree and the current and potential distributions on the bottom left.
Also known as the Blue Quandong, this tree flowers between March and June. The flowers grow off
Racemes as seen above. The distinctive blue fruits that are produced after flowering are about 2-3 cm in
diameter and contain 4-5 seeds [15].
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Cultivation of Elaeocarpus Grandis:
The tree is grown from sowing the seeds; however, it can take up to 12 months before the seeds
germinate. Elaeocarpus Grandis grows rapidly with an ample water supply. This tree grows best on alluvial
soils, but it can also be grown very successfully on various soils derived from basalt [16]. Alluvial soils are
primarily utilised for vegetable cropping which could pose limitations on the propagation of Elaeocarpus
Grandis for oil cropping.
The Elaeocarpus Grandis requires an annual rainfall of 1000-3500 mm and does not cope well with
extended periods without watering. Thus, in order to successfully cultivate this plant for oil cropping,
irrigation systems are necessary. Also, this tree quickly deteriorates in cold climates [16]. Around 350 trees
can be grown per hectare of land [6][15].
The fruits should ideally be picked from the tree upon maturing as this is when they contain the most oil.
Although, as the tree can grow up to 35 m tall, directly picking the fruits from the tree can be inconvenient
or too difficult. Alternatively, the fruits can be collected from the floor once they have dropped off the
tree.
The seeds or entire kernel, seen below, contained within the fruit are easily extracted by peeling away the
fleshy fruit. In a year, a healthy plant can yield about 2 kg of kernels, resulting in 700 kg of kernels per
year, per hectare. The kernels contain, on a unit mass basis, about 38% oil, thus a total of about 270 kg of
oil can be produced per year, per hectare [6].
Figure 13 - Fruit and kernel of Elaeocarpus Grandis.
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3.8 Ochna Serrulata (Ochna)
The Ochna plant is a small understory shrub that grows in subtropical climates, in particular evergreen or
scrub forests. The tree features short-lived yellow flowers which make way for fruits that droop down
from receptacles [17][18]. This plant grows at elevations up to 800 m; however, it does not cope well in
cold climates [18]. The current and potential dispersal of Ochna Serrulata is displayed in Figure 14 below,
along with images of the flowers, fruit and shrub.
Figure 14 - The Ochna Serrulata shrub, with its yellow flowers and the fruits produced. In the bottom right, is the distribution of the shrub in Australia.
The fruits seen above mature and fall off the tree by early summer. As seen, these fruits grow off
receptacles yielding 5 or 6 fruits on each. The fruits themselves contain around 8 seeds each of which are
about 8 mm long. Thus from any receptacle, around 40-48 seeds can be obtained [17].
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Cultivation of Ochna Serrulata:
This is a slow growing shrub that, for purposes of cultivation, requires regular watering. The shrub should
receive a plentiful amount of sunlight and cannot withstand droughts [17]. This drought intolerance is
illustrated in the distribution map on the previous page; the potential distribution only reaches up to the
central coast of Queensland as beyond this point, extended periods without rainfall are expected.
Ochna Serrulata must be grown from direct seeding, where the seeds must be planted as soon as they are
gathered [17]. The shrub grows to a height of 1-3 m and takes up a surface area of about 4 m2. Thus, in a
hectare, up to 2500 plants can be grown [6][18]. The fruits should be collected once they have dropped
off of the plant (during the beginning and until the middle of summer).
The seeds extracted from the fruits, and seen below, are removed simply by squishing the fleshy fruit and
consequently squeezing out the seeds. These seeds contain approximately 30% oil. Each shrub produces
about 0.4 kg of seeds in a year, which totals to around 1000 kg of seeds per hectare, per year. With 30%
oil content, just over 300 kg of oil can be produced per year, per hectare [6].
Figure 15 - Seeds produced by an Ochna Serrulata shrub.
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3.9 Brachychiton Bidwilli
Brachychiton Bidwilli is a perennial plant, usually classed as a shrub but can grow into a small tree. It grows
in dry rainforests and along various coastal regions, such as along central and southern Queensland [19].
This plant generally grows on free-draining soils, but can grow on other variants of sand, loam, clay or
gravel soils [20]. This is a fairly resilient plant that can cope with droughts and has the potential to be
grown throughout Australia [19]. The current and potential distribution of Brachychiton Bidwilli is
presented in Figure 16 . The shrub or tree, flowers in late summer or early spring, after which, the fruits
mature between March and May. Each of the fruits produced contain a number of hairy seeds [19].
Figure 16 - Brachychiton Bidwilli, its current distribution and its potential distribution in Australia.
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Cultivation of Brachychiton Bidwilli:
Best grown from direct seeding, as opposed to being grafted from nurseries, this large shrub grows up to
4 m tall and 3 m wide. Approximately 2700 plants can be grown in a hectare [6]. Brachychiton Bidwilli
grows best in sand or clay soils and requires minimal maintenance [20]. Although this plant can survive
without regular rainfall, to maintain consistent yields, it should be supplied with a constant supply of
water. Furthermore, the acidity of the soil must be within a pH of 6.5-8.5 [20].
This plant can grow in partial shade and in mixed cultures as an understory plant. Due to its tolerance to
dry conditions and capability of growing in mixed cultures, Brachychiton Bidwilli holds a wide propagation
potential. As mentioned, the fruits produced mature between March and May. These fruits should be
collected by picking them from the tree during this time; they can still be collected from the ground if they
have already dropped off. The seeds are extracted from the fruits by breaking them apart once they have
dried. As seen in the figure below, the fruits have a hard shell which splits open, revealing the hairy seeds
within.
Figure 17 - The dried fruit and seeds within of a Brachychiton Bidwilli shrub/tree.
A healthy shrub or tree can produce up to 0.6 kg of seeds in a year, totalling to about 1600 kg of seeds per
hectare. The seeds have an oil content of 15%, yielding just over 240 kg of oil at most, per year, per hectare
[6].
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3.10 Koelreuteria Formosana (Chinese Rain Tree)
The Chinese Rain tree is a moderately sized tree growing up to 18 m tall. Formally known, Koelreuteria
Formosana, this tree typically grows in temperate climates, however it can tolerate a range of conditions
allowing it to be grown in a range of ecosystems [21]. Such conditions range from frost to high heats and
from well-drained to wet soils. Koelreuteria Formosana has also been observed to grow well in areas with
high levels of air pollution [21]. The potential distribution of this plant in Australia is illustrated below.
Displayed in Figure 18 below is a Koelreuteria Formosana tree and the fruits it produces. These fruits grow
from February to March and mature by mid-year. The fruit grows in drooping clusters and grows to about
50 mm in length [21].
Figure 18 - The current and potential distribution of Koelreuteria Formosana, the fruit it bears and a full grown tree.
Cultivation of Koelreuteria Formosana:
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As mentioned, this tree can survive under a fairly wide range of conditions, however, it thrives in warm
climates under full sunlight. Also, this tree can thrive on a number of different soil varieties, but ideally,
the soil should be free-draining [21]. As Koelreuteria Formosana is drought tolerant it has low watering
requirements.
This tree can be successfully grown from direct seeding or transplanting from nurseries. It can grow up to
18 m tall once fully grown and requires little maintenance. Furthermore, Koelreuteria Formosana can be
grown in mixed cultures. On a per hectare basis, about 400 trees can be grown.
The seeds taken from Koelreuteria Formosana are spherical in shape and have a diameter of around 5
mm. These seeds can be seen in Figure 19 below and contain an oil content of about 22% per unit mass
[6]. The fruits that the seeds are drawn from can be collected from the tree upon maturing or gathered
from the surrounding area as they drop off.
Figure 19 - Seeds extracted from the fruit of a Koelreuteria Formosana tree.
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3.11 Santalum Album (Sandalwood)
Sandalwood, formally known as Santalum Album, is a medium sized hemi-parasitic tree that grows to a
height of 8 m. Sandalwood grows in subhumid, low-land wet or dry tropics, hence why it is found along
the more coastal regions of the Northern Territory, as seen in Figure 20 [22]. This hemi-parasitic tree can
survive extended periods of drought when attached to suitably drought tolerant host plants. Also seen in
the figure below is the fruit produced by this tree. Santalum Album has two fruiting seasons; the heavy
fruiting season is from December to February and the light fruiting season is from January to March. These
fruits are urn shaped and grow in small clusters [22]. The fruits are red when ripening and turn a deep,
dark purple once fully matured.
Figure 20 - The Santalum Album (or Sandalwood) tree, its current distribution in Australia and the small clusters of fruit produced.
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Cultivation of Santalum Album:
Being a parasitic plant, it requires a host plant in order to grow and flourish, especially during
establishment. It is grown with greatest success by transplanting from nurseries. Santalum Album grows
on self-draining, light to medium textured soils with full sunlight. Each plant needs a total area of around
4x5 m, accommodating 500 trees per hectare [6][22].
In order for this plant to flourish, it requires a warm to hot climate, having a mean temperature of 23-27 oC. Santalum Album has low watering requirements of 1250-1750 mm annually and can survive periods
of drought of around 5-6 months in length, so long as the host plant is appropriately selected. As such,
once established this plant has very little maintenance or upkeep requirements [22].
The fruits yielded are collected once they have fully matured. The matured fruits can be collected by
trimming the small clusters off the tree or by simply collecting them off the surrounding floor. The fruits
are about 7 mm in diameter and contain a single seed. The seeds are extracted by removing the soft flesh
of the fruit after they have been dried. The dried fruit and seeds within can be seen in the figure below.
Figure 21 - The dried fruit and seeds contained from Santalum Album.
A healthy, mature tree can yield around 40 kg of seeds in a year. Thus, with of 500 trees per hectare,
20000 kg of seed can be produced per year, per hectare. The seeds obtained have an oil content of around
25%, providing a total of 5000 kg of oil per year, per hectare [6].
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3.12 Argemone Mexicana (Mexican poppy)
Argemone Mexicana, seen in Figure 22 below and commonly known as Mexican poppy is an herbaceous
species which is considered as a weed in Australia. This small shrub, usually growing to 1 m tall, is found
in great number in Western Australia [23]. The shrub grows in pastoral areas such as along or near river
beds, on moist flats and on sand dunes. Occurring mainly in regions with a pronounced dry season and on
open waste grounds, this plant has, as seen below, an extremely large potential distribution through
Australia [24].
The Mexican poppy has two fruiting season in the year; the first being during summer and the second
throughout autumn. The fruits have an ovoid shape and a large number of spikes or prickles as can be
seen in Figure 23 [24].
Figure 22 - The current and potential distribution of the Mexican poppy and a fully grown shrub.
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Cultivation of Argemone Mexicana:
This shrub is grown best by sowing seeds just below the soil surface at a depth of around 3 mm. Sowing
should be done in late spring and to ensure success, the soil should be moist with a temperature around
25 oC [24][25]. As mentioned, Mexican poppy is often found on open waste lands, hence this shrub can
grow well on soils with low fertility. Furthermore, this plant grows best under full sunlight [24].
Being drought tolerant, this plant has very low annual rainfall needs, however extensive weed
management is a necessity. This plat cannot survive in mixed cultures and quickly deteriorates in the
presence of other weeds [24]. To add to this, the Mexican poppy is a poisonous plant and thus, plantations
must be made away from sources of wheat and other feed stocks so as to avoid contamination [23].
The shrubs are small and only need 1x0.5 m blocks, giving up to 20000 plants per hectare [6]. In a year, a
healthy shrub can produce between 40 and 90 fruits. The fruits seen below can contain about 400 seeds
each. These seeds are spherical in shape and possess a diameter of about 1 mm [25]. The seeds can be
collected by picking the fruits, once matured, off the tree, allowing them to dry and then cracking open
the shell. Alternatively, the seeds can be separated from the entire plant, as the whole shrub can be
harvested and dried.
With 20000 plants per hectare, 40-90 fruits per plant and around 400 seeds per fruit which have a weight
of approximately 0.006 g, a total of 2100-4200 kg of seed can be produced per year, per hectare. The
seeds have, on a unit mass basis, 24% useful oil, providing an annual yield of 540-1080 kg of oil, per hectare
[6].
Figure 23 - The fruit produced by an Argemone Mexicana plant and the seeds contained.
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3.13 Petalostigma Pubescens (Quinine bush)
The Quinine bush is usually a small tree, growing to typically 3-4 m tall. The tree is found in great
abundance throughout the central highland areas of Queensland. It has also been found in great numbers
through the coastal soils of both Queensland and the Northern Territory [26]. The current distribution of
Petalostigma Pubescens is displayed below. Considering its already large dispersal and the different
conditions in which the plant has been seen to flourish, this small tree has potential to be propagated all
through Western Australia as well.
The Quinine bush blooms during the winter season, this can however depend on the region the plant is
grown [26]. The fruits produced turn orange in colour upon maturing. The fruits can be seen beside the
distribution map, in Figure 24 below.
Figure 24 - A full grown shrub with matured fruits and the current distribution of Petalostigma Pubescens.
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Cultivation of Petalostigma Pubescens:
Petalostigma Pubescens can be easily grown from either direct seeding without the necessity of sowing
treatments or by transplanting plants from nurseries. As seen by its large dispersal, this plant can tolerate
a wide range of soil conditions. Furthermore, it can also tolerate a variety of conditions from minimal
annual rainfall to tropical conditions. Petalsostigma Pubescens, however, does not cope well with frost
and colder conditions [26].
The Quinine bush has been found to flourish even with partial shading, making it ideal for establishment
as an understory plant [26]. The small tree or bush is rather small and so, a total of about 3300 plants can
be grown per hectare [6].
The orange fruits of the Quinine bush are about 2-4 cm in diameter and contain around 10 seeds in each.
A typical tree or bush produces a fairly large quantity of fruits, yielding around 0.4-0.5 kg of seeds in a
year. The fruits should be picked directly from the tree before fully maturing [26]. The fruit has a tough
outer skin which should be dried thoroughly and then peeled away. An example of the dried outer skin of
one of these fruits can be seen in Figure 25.
Figure 25 - Peeled back dry skin of a fruit from a Petalostigma Pubescens plant, revealing the endocarp.
As mentioned, a typical tree or bush can yield about 0.4-0.5 kg of seeds in a year. Thus, with 3300 plants
per hectare, 1300-1650 kg of seeds can be produced per year, per hectare. These seeds have an
approximate 21% oil content, which results in 270-350 kg of oil, per hectare, per year [6].
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3.14 Brachychiton Acerifolius (Flame Tree)
Brachychiton Acerifolius, the Flame tree (see below), is a medium sized tree reaching a height of 30-35 m,
although in colder climates it is typically much smaller. The tree features spectacular floral displays after
hot and dry periods [27]. Brachychiton Acerifolius is a hardy plant that can grow in a range of soils and
thrives in temperate to tropical climates. This tree is wide spread through subtropical rainforests from
northern New South Wales and all the way through Queensland, as seen in Figure 26 below [28].
The Flame tree flowers in late spring to early summer. The fruits following flowering have a capsular shape
and leathery texture. These fruits are large and contain 10-15 seeds [29].
Figure 26 - The current distribution of Brachychiton Acerifolius in Australia, a fully blooming tree and the large fruits produced.
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Cultivation of Brachychiton Acerifolius:
This plant is best propagated from seeding and does not require any form of pre-treatment. The tree can
grow in a large range of soils including heavy clays and sand. It may take however, 5-8 years before a tree
will begin flowering. Alternatively, plants can be grafted using scions from well flowering, mature plants.
Grafted trees flower much earlier than those grown from direct seeding [30].
The Brachychiton Acerifolius is tolerant to both dry conditions and heavy rainfall. It can cope with
droughts, however, it does not deal well with colder temperatures. To add to this, the tree is not tolerant
to harsh or salty winds. Furthermore, the tree does not deal well with medium to high levels of salinity
[30].
For cultivation, trees should be spaced 4x3 m apart, accommodating just over 830 plants per hectare. In
a year, a healthy tree can produce around 2 kg of seeds [6]. These seeds are extracted from the fruit by
allowing the fruit to dry and cracking open the outer shell. Care should be taken when collecting the seeds
as they can cause irritation. The fruits should be picked from the tree when they turn a coppery brown
colour.
Figure 27 - Seeds extracted from a fruit of the Brachychiton Acerifolius.
The hairy seeds seen above contain 20% oil. Thus, with 2 kg of seed per plant and 830 plants per hectare,
a total of around 330 kg of oil can be produced per year, per hectare [6].
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3.15 Jagera Pseudorhus (Jagera)
Jagera Pseudorhus (see Figure 28) commonly referred to as Jagera is a tall shrub or small tree reaching 6-
10 m in height that usually grows in well-developed highland and mountain forests. In Australia, Jager
occurs from north-eastern Queensland to north-eastern New South Wales as seen below. This shrub
flowers between April and May, giving way for a large number of fruits. These fruits feature fine hairs (see
below) that can irritate the skin [31][32].
Figure 28 - Jagera Pseudorhus, its fruits and the current distribution within Australia.
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Cultivation of Jager Pseudorhus:
Jager grows very well in open fields and is planted from fresh seeds. To ensure successful germination the
seeds must be planted as soon after collecting them as possible. This plant can be adapted for a wide
range of free-draining soils and climate conditions, as evident from its large dispersal. This shrub or tree
can also tolerate partial shading, however it responds best to full sunlight [32].
The Jager Pseudorhus is fairly drought tolerant but, for cultivation purposes regular watering is necessary
[32]. The small tree or shrub occupies about 4x3 m of land allowing for just over 830 plants per hectare
[6]. In regards to harvesting, the fruits are fairly large and easy to collect from the tree directly. Care should
be taken when gathering the fruits due to the irritating hairs surrounding them. Each fruit contains a
number of small seeds seen in Figure 29. The seeds are taken out of the fruits by simply peeling open the
relatively tough outer layer.
Figure 29 - Seeds produced by Jagera Pseudorhus.
A healthy shrub can produce around 0.5 kg of seeds in a year. This results in a total of 415 kg of seed per
hectare, per year. The seeds have a useful oil content of 34% totalling to a yearly oil yield of 141 kg per
hectare [6].
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3.16 Ricinus Communis (Castor Oil Seed)
Ricinus Communis (see Figure 30) is a moderately sized shrub that grows to 1-4 m tall. Growing mainly in
riparian habitats such as along water courses and flood plains, this shrub has been declared as a weed for
its rapid propagation and resilience to a number of unfavourable conditions [6][33][34]. The Castor oil
seed shrub is drought tolerant and can flourish in range of temperatures from 7 oC to 28 oC [35]. Due to
its survivability, Ricinus Communis has a very large dispersal through Australia, as illustrated below.
Flowering occurs during late spring and early summer with the fruits being produced by late summer.
Although, Ricinus Communis can bloom throughout the year depending on the conditions, summer is the
main period [34].
Figure 30 - Ricinus Communis, the seeds produced and its current and potential distribution through Australia.
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Cultivation of Ricinus Communis:
This plant is grown from seedlings, which require a rich soil along with daytime temperatures above 20 oC
[35]. The shrub grows best in well-drained, moisture retentive clays or sandy loam, under full sunlight.
The shrub also prefers high temperatures and humidity [35]. Not only is the plant drought tolerant but it
can also grow in soils with high levels of salinity. In addition, Castor oil seed can tolerate short periods of
sub-zero temperatures [36].
Being a weed, Ricinus Communis can grow very well in mixed cultures and in partial shading, allowing it
to be grown as an understory plant for trees possessing minimal foliage. Ricinus Communis should ideally
be spaced 2x1 m for cultivation purposes, accommodating 5000 plants per hectare [6].
A typical healthy shrub can produce a total of about 0.2 kg of seeds in a year. This results in approximately
1000 kg of seed per hectare, per year [35]. The fruits are easily harvested by picking them directly from
the shrubs or simply collecting them from the surrounding area. The seeds are then taken out of the fruits
by cracking them open. This can be done almost immediately after being picked as they are already dry
by the time they are picked. Care should be taken when collecting the seeds as they contain ricin, a potent
poison.
Figure 31 - Seeds produced by Ricinus Communis.
The seeds gathered (and seen above) have a high oil content of about 50% per unit mass. Thus, with 1000
kg of seed, 500 kg of oil can be produced per year, per hectare by Ricinus Communis [6][37].
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3.17 Atalaya Hemiglauca (Whitewood)
The tree seen in Figure 32 is known as Whitewood, a small tree reaching to about 6 m in height. Formally
Atalaya Hemiglauca is a very drought tolerant tree growing throughout the open plains and alluvial flats
of the central regions of Australia as seen below [38]. Atalaya Hemiglauca flowers from spring until early
summer. This tree produces a large quantity of fruits that resemble propeller blades [38]. These fruits (see
below) contain around two or three seeds in each.
Figure 32 - The current distribution of Atalaya Hemiglauca, a full grown tree and the fruits yielded.
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Cultivation of Atalaya Hemiglauca:
The Whitewood tree is easily grown from seedlings in a wide range of soils seen throughout central
Queensland and Northern Territory [38]. It can also be transplanted from nurseries. This tree requires full
sunlight and grows best on coarse sands or clay loams. As mentioned, it is highly drought tolerant and can
also tolerate light frost [38].
This is a fairly small tree, occupying 3x2 m blocks, allowing approximately 1660 trees per hectare [6]. The
fruits can be collected by picking them directly from the tree. In a year, a healthy tree can produce about
2 kg of seed; this results in 3320 kg of seed per hectare, per year [6]. The seeds themselves may be too
inconvenient to be taken out of the fruits due to the tight containment of the seeds. Instead, the entire
fruit can be dried and used. Below is an image of the dried fruit.
Figure 33 Fruits produced by Atalaya Hemiglauca.
The Whitewood seeds contain around 15-20% oil on a unit mass basis. Thus, with 3320 kg of seed per
hectare, per year, a total of around 500-650 kg of oil can be produced [6].
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3.18 Dianella Caerulea (Blue Berry Lily)
Dianella Caerulea is an herbaceous shrub growing to a height of about 0.5-1.3 m, commonly referred to
as the Blue berry Lily for the characteristic purple berries [39]. The soft blue flowers bloom during spring,
followed by the berries [40]. The Blue berry Lily can be found on the east coast of Australia from Torres
Straight island to Tasmania and is most common through New South Wales [39]. A dispersal map of this
plant through New South Wales is displayed below along with an image of the blue flowers.
Figure 34 - Dianella Caerulea, its flowers and a distribution map for New South Wales.
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Cultivation of Dianella Caerulea:
The Blue berry Lily is easily propagated via direct seeding in a wide range of environments. This plant is
known as one of the hardiest plants, tolerating droughts, frost, high humidity and heat [41]. Furthermore,
Dianella Caerulea, can flourish in partial shading and as it grows amongst grasses, it is a suitable
understory species [41].
Once established very little maintenance is required, however, slow release fertilizer should be used every
spring or just before the flowering season [41]. For cultivation purposes a spacing of 1x0.5 m should be
employed, accommodating a total of 20000 plants per hectare [6]. In a year, a typical plant will produce
around 0.11 kg of seed. The seeds can be collected by stripping the stalks that they grow off. The collected
fruits should be either dried or fermented before extracting the seeds.
Figure 35 - Seeds produced by Dianella Caerulea.
The seeds seen above contain about 19% oil. Considering a plant yields 0.11 kg of seed per year, in a
hectare up to 400 kg of oil can be produced [6].
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3.19 Pongamia Pinnata (Karanja)
Growing in the north eastern and central regions of Australia, Karanja is a moderately sized tree growing
up to 15-25 m tall [42]. The tree prefers humid and sub-tropical environments with an average
temperature of 27-38 oC. Pongamia Pinnata has been noted to have an annual rainfall requirement of
500-2500 mm [42]. With the relatively high mean temperature the dispersal of this plant is fairly limited
as seen in Figure 36.
The fruits produced by Pongamia Pinnata grow in clusters as seen below. These fruits feature a pod like
nature with a tough outer shell; they also mature by January-February and contain a number of small
seeds [42][43].
Figure 36 - Pongamia Pinnata, a cluster of the pod fruits and a map of the trees current distribution.
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Cultivation of Pongamia Pinnata:
Karanja is easily cultivated by sowing the seeds in most soil types. The seeds require no pre-treatments
and germinate anywhere between seven days and one month after sowing [42]. Karanja can grow under
either full sun or partial shade and responds well to regular watering [44]. During the first year of growth,
weed control is necessary [42]. Due to nitrogen fixing properties, Pongamia Pinnata requires very little
care once it has been established [42]. As this tree does not deal well with weeds, it is not suitable for
mixed cultures. Trees should be spaced 5x5 m, which is equivalent to 400 trees per hectare [43].
The fruits should be collected once mature directly from the tree. The bunches of fruit are easily collected
by cutting the main stems connecting to the branches off the tree. The fruits are then dried so that the
pods can be cracked open easily, revealing the seeds (see below). Mature trees can yield 8-24 kg of seed
per year [42].
Figure 37 - Seeds produced by Pongamia Pinnata.
Per hectare, a total of 3200-9600 kg of seed can be yielded per year. The seeds contain, on a unit mass
basis, 22% oil. Thus, 700-2200 kg of oil can be produced per year, per hectare of Pongamia Pinnata [6].
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3.20 Cocos Nucifera (Coconut Palm)
Thought by many to be one of the worlds most useful plants, the Coconut Palm cultivated throughout
the world for different reasons, such as food, wood, handicrafts and others [45]. Formally known as Cocos
Nucifera, the tree grows to about 20-22 m tall and prefers warm, humid tropical or subtropical climates
[45]. Cocos Nucifera typically grows in areas with an average temperature of 27 oC and an annual rainfall
of 1500-2500 mm, such as along the central coast of Queensland [45][46].
Fruit is produced throughout the year at regular intervals. The fruits grow in clusters of about 10 coconuts
and each tree can have a number of clusters at any one time. In a year, a mature tree yields 50-80 fruits
[45][46]. The clusters of fruit can be seen alongside a dispersal map below.
Figure 38 - Full grow Cocos Nucifera trees, the bunches of fruit produced and the current distribution in Australia.
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Cultivation of Cocos Nucifera:
Cocos Nucifera is grown from planting the seeds just before they fully mature and right after they have
been collected [45]. This palm is very adaptable, being able to be grown in almost any soil type so long as
waterlogging does not occur within 1 m of the surface [45]. The plant is also tolerant to salt sprays and
medium to high levels of salinity such as in coastal sandy soils [45][46]. Furthermore, the Coconut Palm is
one of the few trees that can withstand cyclonic winds.
During the first few years of growth manure should be regularly supplied to ensure good growth and high
yields [46]. The tree also responds well to regular watering. Once established little care is required to
maintain the health of this plant. These trees can last up to 50 years producing consistent yields each year
so long as they are taken care of appropriately [45][46]. For cultivation purposes, trees should be spaced
7.5x7.5 m apart allowing for up to 180 plants per hectare [46].
The fruits are best collected before maturing by climbing up and cutting down the bunches of fruits. The
fruits can be collected from around the tree once they matured; however, there is the risk of other
coconuts falling during collection [46]. The part of the coconut used to extract oil from is the copra (flesh
of the fruit). In order to get the copra, the fruits thick outer husk must be broken open. The large seeds
inside must also be cracked open, following which, the copra can be ground away from the hard shell of
the seed.
Figure 39 - A cracked open coconut revealing the white copra within.
A healthy tree produces around 35 kg of seeds per year [46]. Each seed contains about 50% oil on a unit
mass basis, meaning each tree yields 17.5 kg of oil in a year. So, per hectare approximately 3150 kg of oil
can be produced per year [6].
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4. Discussion & Evaluation of the Viability for use as a Biodiesel Feed-
Stock
At the onset of the preceding section (Section 3) the key aspects that define what makes a plant species
viable as a biodiesel feed-stock were presented. They are: the environments in which they can be grown,
specific cultivation requirements, in particular harvesting of the seeds or kernels, and the costs associated
with the various aspects of the oil production process.
In order to determine whether a plant species is viable depends greatly upon where, for what purpose
and how the plant species is grown and used. Though much of what determines a plant species to be
viable is relative to a number of external factors, there are generic aspects, properties and requirements
that apply to any plant species in any situation. Such aspects include the application of fungicides,
herbicides, pesticides and other similar maintenance necessities which depict part of the core productivity
requirements. To add to this, the ecosystems to which a plant is suited can be compared and contrasted
irrespective of external factors. Furthermore, the seed or kernel and oil yields per year and the
corresponding requirements for harvesting the seeds or kernels constitute the primary factor to be
considered, as they have implications for productivity requirements and potential gains.
Thus, the base criteria that the plants will be evaluated with are:
1) Seed yields
2) Oil yields
3) Ease of Cultivation
4) Ease of Harvesting
5) Range of Ecosystems in which they can survive
4.1 Harvesting & Potential Yield Analysis:
On the ensuing page is a graph depicting both the yearly oil and seed or kernel yields per hectare. Several
implications can be gained from this graph. Firstly, the seed or kernel yields for each plant grant insight
into the amount of work, energy and cost needed to harvest the seeds or kernels; the greater the seed
yield, the greater the work, energy and cost needed. Conversely, the seed/kernel yields also help illustrate
the productivity, in particular the output, of each plant species. As seen from Figure 40, Santalum Album
clearly has the highest work and energy input due to its 20000 kg seed yield per hectare, per year. To add
to this, Santalum Album has the highest harvesting and processing costs based on the seed/kernel yields.
Examining the yields of Pongamia Pinnata, it can be seen that it also has a relatively high seed yield and
thus work and energy input requirement. Again, due to its relatively high seed yield, it has one of the
greater productivities. From the larger seed yield, a comparatively higher oil yield can be expected,
resulting in a higher rate of work and output.
The oil yields reinforce implications drawn from the seed yields. As expected, both Santalum Album and
Pongamia Pinnata have relatively high oil yields due to their high seed yields. Although, looking at Cocos
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Nucifera, it can be seen that while it has a slightly lower seed yield, it has a much greater oil yield than
Pongamia Pinnata. This demonstrates that Cocos Nucifera has a higher productivity than Pongamia
Pinnata; the former provides more than double the output for more or less the same input. Thus, the
difference between the seed/kernel yields and the oil yields provides a quantitative means of comparing
the productivities of different species irrespective of external factors.
Figure 40 - Graphical Representation of the Oil and Seed or Kernel Yields.
Figure 41 compares the oil content per unit mass of each plant, which helps illustrate the comparative
analysis of the plant species productivity. In much the same way that Cocos Nucifera has a higher
productivity than Pongamia Pinnata, both Calophyllum Inophyllum and Aleurites Moluccana have greater
productivities than Santalum Album, even with its superior seed yield, due to their much higher oil
contents. To add to the productivity, a basic cost-benefit comparison can be made. A plant such as Syagrus
Romanzoffian has a much greater cost-benefit than Brachychiton Bidwilli as both plants have similar seed
yields and hence work, energy and cost requirements however, Syagrus Romanzoffiana has a much
greater oil yield (more is being gained for every bit that is going in). So, a high oil yield with a comparatively
low seed yield, such as Cocos Nucifera, would maximise the productivity and thus the cost-benefit.
Following this, from Figure 41, Aleruties Moluccana, Calophyllum Inophyllum and Cocos Nucifera hold the
greatest viability, closely followed by Santalum Album and Pongamia Pinnata.
0
5000
10000
15000
20000
25000
We
igh
t (k
g)
Comparison of Oil Yields Per Hectare, Per Year
Seed Yields
Oil Yields
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0
10
20
30
40
50
60
Oil
Co
nte
nt
Pe
r U
nit
Mas
s (%
)Oil Content of Each Plant Species
Figure 41 - A comparison of the oil content by mass.
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4.2 Cultivation Analysis:
The preceding discussion has revealed a number of plants are superior based on their productivity and
cost-benefit, as evident from seed/kernel and oil production. Appendix i contains the primary information
relating to the cultivation requirements of the plant species. Due to the previous discussion, five plants
were highlighted as they had the most significant oil and seed/kernel yields and that this implied that they
also have a higher productivity. This however, does not draw any connections from either the specific
cultivation requirements of each plant or the costs of collecting and processing the seeds/kernels.
As seen from Table 1, both Calophyllum Inophyllum and Aleurites Moluccana, though they grow in a large
number of different soil conditions and a fairly wide range of climates, neither can be grown very well in
the more central regions of Australia. On the other hand, plants such as Atalaya Hemiglauca, Argemone
Mexicana and Ricinus Communis can be grown almost anywhere in Australia; particularly Ricinus
Communis and Argemone Mexicana as they can both be grown on infertile waste lands. Most of the plant
species studied currently grow along the east coast through Queensland and many reaching down into
New South Wales.
Looking back at Figure 41, it can be seen that Argemone Mexicana has the sixth highest oil and seed yields
per hectare, per year, making it a very versatile plant that can provide a moderate productivity. Looking
at Santalum Album and referring back to the map in Figure 20, this plant grows in a very limited region,
primarily due to its hemi-parasitic nature. So, although this plant has one of the highest oil yields, it has
limited propagation. Similarly, Elaeocarpus Grandis grows best on alluvial soils, which poses severe
limitations on its propagation as alluvial soils are widely used for vegetable crops.
Another factor to be considered is the collection of the fruits from the plants and the difficulty of
extracting the seeds or kernels. Many of the plants yield small soft fruits which can be easily picked by the
bunch off the plants and then squashed revealing the seeds. On the other hand, there are many fruits or
seeds such as those from Calophyllum Inophyllum or Aleurites Moluccana that have tough endocarps and
so must be dried thoroughly in order to retrieve the desired raw product. Another such example is
Brachychiton Bidwilli which has fruits featuring a tough outer skin. Although some fruits need to be dried
out in order to gain the seed or kernel there is not much difference in the work required. The only concern
is with Argemone Mexicana and Ricinus Communis. Argemone Mexicana fruits feature large prickles and
a tough skin making both collection of the fruits and extraction of the seeds a potential risk, requiring
additional work relative to other plant fruits, while Ricinus Communis fruits contain a potent poison, ricin.
Furthermore, plants such as Syagrus Romanzoffiana and Cocos Nucifera are harvested by the bunch from
their respective trees. This makes collection of the fruits very easy. Once again, the fruit from Calophyllum
Inophyllum and Aleurites Moluccana are picked one by one making for a much more laborious harvest.
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A final deliberation must be made on account of the costs associated with the plant species. There are
many costs that cannot be predetermined without knowing specific details about where the plant is to be
cultivated (external factors) however, in Table 1 is a column that contains the wholesale costs of the seeds
per kg. This cost provides great insight into the ease of fruit collection and cultivation of the plants; lower
costs imply wide spread cultivation of the plant and demonstrate greater productivities. This however,
does not take into consideration that many of the plants under consideration have never been cultivated.
Nevertheless, from these costs, Cocos Nucifera, Aleurites Moluccana and Syagrus Romanzoffiana have
the lowest seed costs which clearly demonstrate the wide spread cultivation of these plants and the ease
of harvesting, particularly so with Cocos Nucifera costing less than 1 AUD per kg when bought in bulk. The
costs range up to 1633 AUD per kg of seed for Elaeocarpus Grandis.
Thus, based on the above considerations, Cocos Nucifera, Atalaya Hemiglauca, Aleurites Moluccana,
Callophyllum Inophyllum and Syagrus Romanzoffiana possess the greatest viability. Cocos Nucifera,
Aleurites Moluccana, Calophyllum Inophyllum and Syagrus Romanzoffiana, can all be grown along the
coast of Queensland and the Northern Territory and if provided with sufficient watering (or irrigation) can
be grown towards the more central regions of Australia. It should also be noted that both Cocos Nucifera
and Calophyllum Inophyllum are two of the only plants that can withstand cyclonic winds.
The above conclusion does not include the possibility of mixed species plantations. Many of the smaller
shrubs and trees can grow in partial shade as understory plants allowing for the cultivation of multiple
crops at once. This may alter the yields of each plant due to the sharing of resources and minerals and
would