looking back at 75 years of research in wood … wood-preservers’ association133 1986 looking back...

AMERICAN WOOD-PRESERVERS’ ASSOCIATION 133

1986

Looking Back at 75 Years of Research in Wood Preservation at theU.S. Forest Products Laboratory

ROY H. BAECHLERChemist (Retired), Sun City, AZ

and

LEE R. GJOVIKResearch Specialist- Wood Pres., Forest Products Laboratory, Madison, WI

Introduction

In 1874 Franklin B. Hough was named the firstAmerican Forestry Agent for the newly formed For-est Commission with the mission to study forest con-sumption. In 1880 the Commission was elevated toDivision of Forestry status and in 1901 the Divisionwas elevated to Bureau status. Along with thischange, Gifford Pinchot was appointed Chief. Nowfor the first time, special emphasis was put on forestmanagement as it would relate to forest productsutilization. This marked the real beginning of ForestProducts Research in the field of wood preservationby the U.S. Government. Pinchot appointed Hermanvon Shrenk (Figure 4) as agent for the Office ofForest Products. His assignment was to initiate stud-ies to show condition, cause, and prevention of decayin railroad ties, which were being used at a rate of110 million ties / year. The Bureau of Forest waschanged to the U.S. Forest Service in 1904. The newForest Service also got control of the national forests.

The first meeting of the Wood Preservers’ Asso-ciation was held in 1904. Six years later the U.S.Forest Products Laboratory (Figure 1, 2, & 3) wasestablished in Madison, Wisconsin, to conduct re-search aimed at the wise and efficient utilization ofthe products from the nation’s forest resource. It wasnot until 1912 that the Wood Preservers’ Associationchanged its name to become the American WoodPreservers’ Association (AWPA).

At one of the early meetings of the AWPA, theDirector of the Forest Products Laboratory (FPL)listed some of the problems in wood preservationthat the Laboratory planned to devote research timeto. In the intervening years, the AWPA has been aconsistent supporter of the FPL and has received

much help in return. Since the FPL has just cele-brated its 75th Anniversary, the present meetingseemed to be an opportune time to review some ofthe Government and industry-supported researchthat had taken place over the years. When possible,we will access the improvements which have beenachieved and to consider measures to solve the manyproblems that still remain.

This paper will deal mainly with research at theFPL since that is the subject most familiar to theauthors. There will be limited references to the lit-erature. It is assumed that the reader has access tothe AWPA Proceedings, and most of the referencesto papers published in other journals. The authorsregret that limitation on their time prevents themfrom recognizing the many excellent papers by ear-lier investigators and from mentioning the countlesscontributions and practical observations made byproducers and users of treated wood.

Beginning of Research at FPL

In 1910 the FPL was established in Madison, Wis-consin, with McGarvey Cline (Figure 5) as the firstDirector. The FPL was organized into various sec-tions or divisions, each concerned with a major lineof investigation and each area under the supervisionof an experienced Division Chief. The first four di-visions in the organization were: Wood Preservation,Timber Tests, Wood Chemistry, and Wood Tech-nology. These four original divisions were soon in-creased to eight with the new areas being:Engineering, Pathology, Wood Distillation, and Pulpand Paper. The first chief of the section of Woodpreservation was F. M. Bond. It was recognized that

134 AMERICAN WOOD-PRESERVERS’ ASSOCIATION

Howard F. Weiss was the most experienced woodpreservation expert when the Laboratory started,but his experience was needed in administration.Weiss became as Assistant Director under McGarveyCline at the time of the Laboratory opening.

Ernest Bateman (Figure 14) was one of the firstemployees at FPL back in 1910 who was placed incharge of the section of Wood Chemistry. He waslater to have a very distinguished career in WoodPreservation research.

Clyde Teesdale succeeded Bond as the Wood Pres-ervation Section Chief in 1917. At the time theUnited States found itself involved in World War I

which necessitated a profound revamping of woodpreservation research. Wood preservation was setaside and activities such as adhesives, moisture-proofcoatings, and propeller manufacturer were the pri-mary duties of the wood preservation staff, whichhad swollen to 71 members during this war timeactivity. Teesdale, assisted by George Hunt, was incharge of these war-time activities.

In 1919, George Hunt (Figure 8) became Chief ofthe Wood Preservation section. In the 1920's underhis guidance, the wood preservation division ex-panded into several new areas of research. Thesewere glues, plywood, laminated construction, andwood finishing. The wood preservation work wasdivided into two general areas of activity, processingtechnology and chemistry of wood presenatives.Hunt was primarily concerned with the methods ofapplying preservatives, while Bateman and his as-sistants devoted much of their time to the chemistryof wood preservatives investigating the relationshipbetween viscosity of preservatives and its penetra-tion into wood in response to various treating con-ditions. One of Bateman’s assistants was RoyBaechler, who joined the Laboratory in 1922 in thechemistry division, also assisting J. D. McLean in thewood preservation division.

The division of plant pathology of Washington,D.C. established a project in Madison during thistime. This group had the responsibility to investigatethe fungi that were responsible for decay of wood.R. H. Colley headed up this group which continuedto be administered from Washington and occupiedquarters in a building near the Forest Products Lab-oratory. Their facilities for toxicity testing were usedextensively by Bateman’s group.

During this period, the Directorship of the Lab-oratory saw some changes also. Howard Weiss (Fig-ure 6) was Director from 1913 to 1917. Carlile P.Winslow (Figure 7) succeeded Weiss and served asthe Director until 1946 which spans two World Warsand countless trials and tribulations. The Laboratorywent from a staff of 80 in 1919 to the largest orga-nization in the world devoted to research on utili-zation of wood and related products with a staff ofnearly 700 in 1945,

The following is the list of all the FPL Directorsto the present:

McGarvey Cline 1909-1912Howard Weiss 1912-1917Carlile P. Winslow 1917-1946George W. Hunt 1946-1951J. Alfred Hall 1951-1959Edward G. Locke 1959-1966Herbert O. Fleischer 1966-1975Robert L. Youngs 1975-1985John R. Erickson 1985-Present

Experiments in wood preservation were one of thefirst research activities in the Bureau of Forestry (theforerunner to the U.S. Forest Service), beginning in1902. Wood preservation research at the FPL madesignificant gains from 1910 to 1917, both in funda-mental and practical research. Prior to the estab-lishment of the Madison laboratory, the preservationwork was confined largely to demonstrations andsome field tests. There was considerable cooperationwith railroads, mining companies, and utility com-panies. The main preservatives were creosote andzinc chloride. The Madison laboratory turned its at-tention to field tests, fundamental studies, and dem-onstrations of wood preservation. During these earlyyears, some of the fundamental studies involvedchemical, physical, and toxic qualities of variouswood preservatives and investigations to improvethe processes of preservation. The Laboratory stillhas an active study dating back to 1910 which dealswith the performance of treated and untreated woodand bears the title, “Service Records on Treated andUntreated Fence Posts.”

In 1910, there were some 70 treating plants in theUnited States. The field testing was essential to solv-ing a pressing problem in the lack of standardizationof preservative and preservative processes and toassist the consumer who is faced with a perplexingproblem of uncertainty as to just what preservativeto use which would yield the best performance forthe end use intended. To alleviate some of the con-fusion, the FPL undertook exhaustive tests on a numb-er of commercial creosotes and other preservativesin order to classify them as to quality. At the sametime, the wood preservation researchers were deal-ing with various treatment processes to improvepreservation penetration. This, we might add, is aproblem which still seems to be with us today.

Cooperative projects with various companies con-stituted a large part of the FPL wood preservationwork in the form of field testing and help in thedesign of wood preservation plants. The FPL couldtake significant credit for wood preservation expan-sion of some 70 treating plants in 1910 to over 100plants in 1915. With preservative testing and re-search to the physical and chemical requirements of


wood preservation, the industry was placed on asound scientific basis.

The Forest Products Laboratory has been an ac-tive participant in matters of AWPA since the be-ginning. One measure of contribution is the numberof published research papers. The AWPA has pub-lished over-1100 papers since 1905. Of these, 220 or20% of the papers were by FPL authors. Also im-portant is the continuous involvement staff fromFPL have had in the technical committees of theassociation.

Wood Preservation Research at FPL BetweenWorld War I and World War II

As mentioned above, service tests were among thefirst projects to be started. A fundamental study ofthe various factors affecting results obtained in pres-sure treatments was started by J. D. MacLean (Fig-ure 15) in approximately 1920. This comprehensiveinvestigation extended over many years. In additionto experiments made with the pilot-plant cylinderat Madison, MacLean visited treating plants oper-ated by several railroad companies and collecteddata on the effect of several treating variables, in-cluding species, on the absorption and penetrationof preservatives. The results of this investigationwere summarized in the document, “PreservativeTreatment of Wood by Pressure Methods”, U.S. De-partment of Agriculture Handbook 40, revised in1960.

In the Chemistry Division, Bateman had startedthe chemical and physical properties of differenttypes of commercial creosotes. The results were pub-lished in U.S. Department of Agriculture Bulletin1036 (October 20, 1922).

In the early 1920’s, Bateman and C. Henningsenstarted a series of theoretical studies entitled ‘“A The-ory of the Mechanism of the Protection of WoodPreservatives.” Eight papers were presented at sub-sequent AWPA annual meeting beginning in 1920.

At the 1930 meeting, G. M. Hunt and T. E. Snyderof the Bureau of Entomology and Plant Quarantinepublished an installation report describing four setsof 2x4x18-inch specimens that were prepared atMadison and treated with various preservatives. Oneset each of the specimens was sent to four tropicalareas that were known to be heavily infested withtermites. These were inspected periodically for anumber of years.

Toxicity of Chemicals to Fungi

In 1922, R. H. Baechler (Figure 18) reported forwork at FPL and was assigned to assist E. Bateman.It had been planned to start an investigation of theeffect of the molecular structure of organic com-pounds on their toxicity to wood-destroying fungi.The practical objective was to find chemicals which

could be dissolved in low-cost petroleum oils to formoil-type preservatives. The project was extended toinclude water-borne chemicals in later years. Thiswas considered a continuous project for an indefiniteperiod, despite interruptions which in some caseslasted for several years. By means of the agar-flasktechnique, determinations were made of the mini-mum concentrations required to prevent the growthof Fomes annosus. In a paper giving data on a largenumber of chemicals at the 1937 AWPA meeting,Bateman and Baechler stated that “Of all the chem-icals that were found to kill our test organism, tet-rachlorophenol and pentachlorophenol were thecheapest sources of toxic action.” It was further re-ported that 3 percent and 5 percent solutions of eachchemical had been used to treat sets of one hundredsouthern pine fence posts which were installed inthe Forest Service test site in Mississippi.

Three members of the FPL staff were involved inpapers presented at the 1941 AWPA meeting. Huntand Snyder presented the 12th Progress Report onthe International Termite Tests. R. M. Wirka gavea detailed account of the start of the Mississippi fencepost study with data obtained after approximatelythree years. This ultimately proved to be the first ofthe series of many progress reports on these tests.R. H. Baechler presented data on the resistance toleaching and the decay protection of various precipitates formed in wood by double diffusion.

A Glance at the U.S. Wood-Preserving Industry in1922

During Baechler’s break-in period, Bateman dis-cussed the basic principles of wood preservation andalso the nature and objectives of FPL projects re-lating to the subjects. During these talks, Batemanmentioned some features of the current wood pre-serving industry.

At this time the treatment of crossties dominatedthe industry. It comprised approximately 90 percentof the total volume of wood treated. Most treatmentswere made in plants owned by railroad companies,although a trend had started toward the sale of treat-ing plants to companies whose sole business was theproduction and sale of treated wood items.

Next to sawn crossties, bridge timbers accountedfor the largest total volume of sawn wood that wastreated. Efforts had been made to convince the rail-road companies that it would be profitable to treatlumber prior to its use in the construction of railroadcars. For many years these efforts met with little orno success. The total volume of lumber that wastrated at this time did not justify its inclusion instatistics on wood treatment.

The total volume of wood in the form of polestreated in 1922 was small but an upward trend hadstarted. Up to this time, naturally-durable species,


such as chestnut and the cedars, were available insufficient quantities to fill the needs of pole users.However, supplies of chestnut poles were shrinkingas the result of the ravages of the chestnut blight.At the same time, readily accessible stands of thecedars were becoming harder to find. It was easy toforesee that before long it would be necessary to usepoles of nondurable species that required preserv-ative treatment in order to yield satisfactory servicelife. The year 1922 could be considered the begin-ning of this trend.

Another trend that was noticeable at this timerelated to the type of preservative used to treat cross-ties. Because of its low cost, zinc chloride had beenfavored over creosote by many who recognized thesuperiority of creosote for this use. However, annualstatistics had shown that the percentage of crosstiestreated with creosote and creosote-tar solutions wasincreasing. In 1922, creosote and its solutions hadovertaken zinc chloride according to the statisticspublished in the following year.

In retrospect, it might have been said that creo-sote-petroleum solutions were in a transition stage.Correspondence with users of treated wood indi-cated a gradual increase in the number of crosstiestreated with such solutions. Several years later, creo-sote-petroleum solutions were included in the sta-tistics on wood presentation.

Wood Preservation Research During World War II

Importation of creosote from Europe was sus-pended during the war and for several years afterpeace was declared. The supply of domestic creosotedid not meet the demand. Information on substitutematerials was urgently needed. In the face of thissituation, research in wood preservation declinedsharply. Inspections of material in field tests werereduced to a minimum. The search for new knowl-edge of wood preservation was at a low ebb.

At FPL most of the personnel that had been en-gaged in wood preservation research were trans-ferred to projects of immediate military importance.For example, Baechler was shifted to the wood-hy-drolysis project in the Chemistry Division. This proj-ect consisted of experiments to develop the mostefficient procedure for hydrolyzing chipped woodwith dilute mineral acids in order to obtain hydrol-ysates that could be neutralized and fermented toethyl alcohol. Required for the production of syn-thetic rubber and other materials, ethyl alcohol wasin short supply throughout the war. The process thatwas developed was practical under wartime condi-tions. It was not competitive in cost with other meth-ods of producing alcohol after peace was declared.Baeclder also investigated a number of domestic and

foreign species to ascertain their suitability for usein chemical engineering construction.l

From World War II to Vietnam

The declaration of peace was soon followed byabrupt changes in the research program of FPL. Ineach division, some projects that had been sus-pended for the duration of the war were not re-sumed. In addition, several new projects appearedon the program. A few of these expanded quite rap-idly and commanded the time of a small group ofstaff members. While some new studies were com-pleted in a relatively short time, others were veryactive for extended periods after which they wereeither terminated or continued at a low rate. Thefluctuations in the emphasis on different projectsoften reflected changes in the nation’s economy.

Assistance to the Rural Electrification Administra-tion

A rapid increase in the construction of power linesby the Rural Electrification Administration (REA)presented many technical problems. Some involvedthe treatment of poles and crossarms on which REAsought the advice of FPL. J. O. Blew (Figure 19) andcoworkers participated in the development of spec-ifications for the treatments. They also compared therelative effectiveness of a number of formulationsfor groundline treatments. An extensive program ofservice tests was started. Ultimately, REA greatlyexpanded its technical staff in the Washington, D.C.office, whereby, its need for assistance by FPLgreatly decreased.

Nonpressure Treatment of Fence Posts

As a branch of the U.S. Department of Agriculture,the Forest Service had long been encouraged to in-vestigate potentially practical methods for treatingfense posts on the farm. At the 1904 World’s Fair inSt. Louis, Herman von Schrenk, a Forest Serviceemployee at the time, demonstrated the creosotingof fence posts in an open tank. During early yearsat FPL, experiments were made on the treatmentof fence posts in open tanks. A virtual boom in suchexperiments occured in southern forestry schoolsduring the years following World War II. This co-incided with a change in the agricultural economyof the South in which many farmers were replacingthe growing of cotton with the raising of cattle. More

1 Baechler, R. H. Wood in Chemical EngineeringConstruction, For. Prod. Res. Soc., 1954, Preprint566.


fences were needed and, since the abundant south-ern pine lacked resistance to decay and termites,low-cost preservative treatments seemed to be apractical answer.

A project to develop a simple, nonpressure treat-ment of fence posts was started at each forestryschool in the south. Their interest was not confinedto simple methods that could be used on the indi-vidual farm, but also, methods that would be prac-tical for use in small plants that could be operatedeither by private enterprise, by cooperative groups,or by counties.

The conferences held at southern Forestry Schoolswere attended by FPL persomel, who conductedsimilar experiments in Madison. J. O. Blew and co-workers tried soaking the posts in a solution of pentain fuel oil of low viscosity. Their results agreed in ageneral way with those obtained in the south. Thepresence of biological attack that developed duringseasoning influenced the uptake of the solution. Ab-sorption of preservatives varied over a wide range—from amounts that were too low to give good pro-tection, to amounts that were excessive from thestandpoint of cost. Blew, et. al., experimented withthe end-steeping of posts in aqueous solutions ofchemicals. Most hardwoods absorbed smalleramounts than did pine, and in those hardwoods thatseemed to be fairly well treated, subsequent fieldtests showed poor resistance to decay and termites.

Baechler and Roth investigated the applicabilityof double diffusion, both by complete immersion ofthe posts and by standing them upright in barrels.Pine posts treated in tanks by double diffusion andinstalled in the Mississippi test plot, prior to the war,were showing excellent results. (Several small post-trating plants using some version of the basic methodhave now been in successful operation for over thirtyyears.)

The ‘“standing-in-barrels” procedure offered theadvantage of requiring only low-cost equipment(used oil drums). Several combinations of chemicalswere tried. After about five years’ exposure, the re-sults seemed quite promising, the main cause of thefew failures being top decay. Some modifications inthe method aimed at reducing this difficulty wereunder consideration when the project was inter-rupted by work of higher priority. These experi-ments were not resumed as the interest in suchtreatments had declined with changes in domesticagricultural economy. In pioneering times, the typ-ical, small American farm was quite self sufficient.The combination of factors such as the developmentof the automobile, the improvement of roads, andavailability of cheap motor fuel, in effect, broughtthe shopping center closer to the farm. This reducedthe incentive for many do-it-yourself activities onthe farm, including the treatment of fence posts. This

illustrates another point. Because of the lack of acompletely reliable, short-time test to evaluate a newmaterial or method for wood preservation, the prac-tical potential of a new idea may be affected ad-versely by changes in the nation’s economy.

Assay of Treated Wood

As was mentioned previously, most preservativetreatments in the country during the early days weremade in plants operated by railroad companies.Since the producer and user were the same, therewas little need for either specifications or for meth-ods to check the quality of treatment. With the de-velopment of commercial wood treating, theproducer and ultimate user of the treated wood wereno longer the same. This lead to a need for detailedspecifications. For many years such specificationscovered penetrations of the preservative as shownby borings. Retentions were generally based on thereadings of tank gauges before and after treatment.It was known that this method of determining theretention for a charge was subject to considerableerror. Purchasers of treated wood, therefore, lookedtoward a method based on the analysis of boringsfrom the treated wood. A few experiments along thisline were made at the Bell Telephone Laboratories,prior to the war, with inconclusive results. In theearly 1950’s a manufacturer of creosote financed astudy at FPL to ascertain the feasibility of such amethod.

A parallel project was conducted at the Bell Tele-phone Laboratories. The results obtained on creo-soted pine poles at both Laboratories were fairlyencouraging and gradually led to the use of themethod in commercial treatments. Later the FPLstudied the method for use on heavily creosotedmarine piling and on lumber treated with bothwater-borne preservatives, and oil-type preserva-tives.

From this early beginning, results-type specifica-tions are now common place in industry. There areonly a few commodities which are not tested forpreservative retention by chemical assay after treat-ment. The most common of these products is railroadties.

The Evaluation of Wood Preservatives in the Lab-oratory

As new preservatives were being developed it be-came apparent that faster methods of evaluatingthese systems were needed. Early work by John Leu-tritz, Reg Coney (Figure 25), Audrey Richards (Fig-ure 24) and Catherine Duncan (Figure 27) was veryimportant in the development and standardizationof the Laboratory soil-block test method. This system


permitted a rapid screening of candidate wood pre-servatives and allowed the comparison of differentpreservatives. The 1950’s saw a series of such pub-lished evaluations in AWPA by Duncan and her co-workers.

The Deterioration of Wood in Cooling Towers

For many years FPL had received occasional in-quiries regarding the deterioration of wood in cool-ing towers. An increase in the frequency of suchinquiries was observed shortly after World War II.Investigators in England had reported the findingof organisms in British cooling towers. That differedin nature from true basidiomycete wood destroyers.

In view of the fact that towers in this country werebuilt of redwood, a naturally durable species, it wasat first assumed that the deterioration of the woodwas due mainly to the chemicals in the water. Inmany towers, the water was maintained at a fairlyhigh pH to combat corrosion of heat exchangers andother steel equipment. Furthermore, it was sus-pected that in some towers, chlorine, used in an

algaecide, was used at concentrations harmful to thewood.

However, as many samples of deteriorated woodfrom towers were studied in the Laboratory, it wasfound that practically all showed biological deteri-oration. Samples from the nonflooded parts of towersshowed the presence of typical basidiomycete wooddestroyers. Approximately ten basidiomycete fungi,both white- and brown-rots, were isolated fromdomestic cooling towers. They were isolated fromthe structural members which were not constantlywet.

Samples from slates in the flooded portions of tow-ers were free from attack by basidiomycetes. How-ever, many showed surface attack by differentorganisms designated as soft-rot fungi. They cause asoftening of the surface and a gradual loss of crosssection, especially in the case of thin slats. It seemedobvious that so long as it was impractical to changethe treatment of the water appreciably, it was ad-visable to use wood treated with a leach-resistantpreservative in the construction of towers. This isnow a routine practice and the problem of prema-


ture decay of wood in cooling towers has virtuallydisappeared. 2

As has been mentioned, a branch of the Divisionof Plant Pathology with headquarters in Washington,D. C., was established in Madison to work in coop-eration with the Forest Products Laboratory. Thisgroup made many contributions to the science ofwood preservation. Their participation in the de-velopment of the soil-block method has been men-tioned. A paper on soft-rot fungi by Duncan in the1960 AWPA Proceedings called attention to the roleof these organisms, especially in the surface decayof hardwoods under wet conditions. These organismswere also found to decay leached redwood slats inthe flooded parts of cooling towers. Lindgren pub-lished a paper in the 1952 Proceedings on the“Permeability of Southern Pine as Affected by Moldand Other Fungus Infections.”

Dual Treatment of Marine Piling

At the time when the first railroads were built inthis country, little thought was given to a preserv-ative treatment of the crossties. Wooded areas werebeing cleared for agriculture and wood was verycheap. Also, species with a fair degree of naturaldurability were abundant in many areas and the ser-vice life of untreated ties was considered satisfactoryas a rule.

On the other hand, untreated pilings driven incoastal harbors were subject to rapid deteriorationby several types of organisms called “marine borers”.In some harbors, untreated pilings were destroyedin less than a year. Some form of protection wasessential and many were tried.

The principal scourge of piling in the colder Amer-ican harbors were several species of terdo. Theypenetrated a pile in the form of tiny embryo whichgrew to worm-like forms in the interior and were,therefore, termed “ship worms”.

An entirely different type of marine organism,called Limnoria, became established in small tunnelson the surface of the wood. Smaller than a grain ofrice, they are extremely prolific and graduallyhoneycombed the surface of a pile. They wereespecially destructive in warm harbors.

The papers discussing the marine borer problemin the early Proceedings of the AWPA dealt mainlywith teredo. Although, occasional references to Lim-noria may be found, construction engineers and

2 Causes and Prevention of Decay of Wood in Cool-ing Towers, by R. H. Baechler, J. O. Blew and Cath-erine Duncan, presented at the PetroleumMechanical Engineering Conference, Kansas City,Mo., Sept. 26-27, 1961.

wood preservation specialists seemed to be con-cerned mainly with preventing attack by teredo. Sev-eral explanations suggest themselves. The growth ofLimnoria is relatively slow except in tropical or sub-tropical harbors. Many of our first harbor structureswere build along our northern coasts.

It had been found in Europe that a thorough im-pregnation with coal-tar creosote gave excellent pro-tection against teredo. Later, experiments showedthat while the adult teredo were resistant to creosote,the embryo were extremely susceptible to its toxicaction. These facts pointed to two precautions,namely, to avoid mechanical damage to the heavily-creosoted, outer layers and to avoid the attachmentof untreated bracing.

As more and more creosoted piling was used inwarmer harbors, it became evident that even whentreated with high retentions of creosote, such pilingswere quite vulnerable to destruction by Limnoria.A species called Limnoria tripunctata, commonlyfound in the warmer harbors, was especially destruc-tive.

Experiments on Limnoria, grown in the Labora-tory and exposed to many different chemicals,showed that Limnoria are quite susceptible to cop-per. This pointed to a procedure that became knownas the dual treatment. It comprised a pressure treat-ment with an aqueous solution of copper and arseniccompounds, whereby a precipitate of very low sol-ubility was deposited in the wood. After the woodso treated was seasoned, it was pressure treated withcreosote.

When wood specimens of various sizes weretreated in the manner described and exposed in har-bors infested with both toredo and Limnoria, theyshowed excellent resistance to both types of marineborers. A number of commercial charges of pilingwere treated and seasoned.

When the pilings were transported to several har-bors and driven, it was found that the treatment hadembrittled the wood. This unfortunate side effectplus the added cost and the need for more lead timemore or less nullified the usefulness of the dual treat-ment for most purposes.

The foregoing experience illustrates the frustrat-ing disappointments with which the researcher mustlearn to live.

Studies of Coal-Tar Creosote

Importation of coal-tar creosote from Europe wassuspended abruptly at the beginning of World-WarII, and was not resumed to a normal rate for severalyears after peace was declared. Since the Americanwood-treating industry had depended upon import-ation for nearly one-third of the creosote used, ashortage of creosote soon developed. For several rea-


sons, the domestic producers of creosote were ableto increase their output only to a limited extent andthe use of substitute materials increased. There wasalso an increase in rumors concerning fraudulentpractices used to extend the supply of creosote.

At the same time, there was an increase in thedemand for certain chemicals which were normallypresent in creosote, especially naphthaline and low-boiling tar acids. These were being removed in in-creasing amounts. Questions arose as to the preserv-ative value of the remaining creosote. The producersdeclared that these chemicals had been removed invariable amounts for many years with no apparenteffect on the effectiveness of the creosote as a woodpreservative.

To obtain some information which would help toanswer these controversial questions, a cooperativeresearch project was started in 1948. The partici-pants were: (1) two domestic producers of creosote,(2) an importer of creosote, (3) a commercial wood-treating company, (4) the Forest Products Labora-tory and, (5) the Wm. F. Clapp Laboratory. After theproject was underway, it was expanded to includetests on 3/4-inch stakes by the Bell Telephone Lab-oratory, the Allied Chemical Corp., and the KoppersWood Preserving Division. The organization andobjectives of the project were covered in a paper byR. H. Baechler, et.al., presented at the 1950 AWPAConvention.

To summarize the findings on field and marinetests, the first results were obtained from marinetests on small treated panels exposed in two harbors.Relatively low retentions were used in order to ac-celerate the results. The data were erratic so thatonly a few conclusions were possible. A 70-30 creo-sote-tar solution was somewhat superior to straightcreosote and definitely superior to a 70-30 creosote-petroleum solution. There was no consistent patternin the effectiveness of the eight creosotes that hadbeen distilled from the same tar. Creosote distilledfrom a high-temperature, coal-tar were definitelysuperior to a creosote distilled from a vertical-retorttar.

The next tests to be reported on were made on3/4-inch, pine sapwood stakes treated with the orig-inal oils that were not designated as the “1948 co-operative creosotes”. The stakes were exposed intwo southern plots. In a report by Coney, et al., inthe 1962 AWPA Proceedings, the authors discussedin considerable detail the sources of experimentalerror in field tests. The depreciation curves indicatethat as a general trend, high-residue and medium-residue oils perform somewhat better than low-res-idue oils.

In a paper summarizing the results of tests by FPLon treated posts and 2x4-inch stakes, the effects ofthe size and shape of the test specimen as well as

the exposure conditions were again dramaticallydemonstrated. The performance of stakes treated toretentions of 8 pcf. was excellent in Wisconsin, buthardly acceptable in Mississippi. The removal ofnaphthalene and tar-acids from the creosote had noserious effect on the preservative value.

There was a large spread in the distillation patternsof the eight creosotes distilled from the same parenttar. However, the variability in service life of the2x4-inch stakes treated with these oils was surpris-ingly small with the exception of oils No. 1 and No.12. These creosotes were very high in distillage to235° and give relatively poor protection.

The fact that the rate of depletion of creosote fromtreated wood was influenced by climatic factors aswell as the size and shape of the specimen was widelyrecognized. There was more tendency to overlooka third factor, namely, the normal position of thewood product in service. In products that were usedin a vertical position, for example, poles, posts andpiles, there is a gradual downward movement ofcreosote. Many who were aware of this phenomenonwere unaware of the magnitude of it. In the 1950Proceedings of AWPA, J. W, Andrews, S. N. Buco,and P. O’Brien described an experiment in whichthe amount of residual creosote was determined insamples removed from a southern pine pole that hadbeen in service for 23 years after being treated in acharge that retained 8.6 pcf. of creosote. After re-moval, the pole was sectioned and samples removedfrom different locations were extracted with hottoluene and pyridine. A sample from just aboveground line yielded 14.8 pcf., whereas, a correspond-ing sample from the approximate middle of the airsection yielded only 4.8 pfc.

In a paper presented by Coney, et.al., at the 1980AWPA Convention, data were given comparing theindex of condition of round posts and 3/14-inch stakestreated with various oils. When a low-residue creo-sote (see), was compared with several high-residuecreosotes, the results obtained with stakes differedconsiderably from the results obtained with posts. Inthe stake tests, the high-residue creosotes were dis-tinctly superior, but in the post tests, showed littledifference.

Acknowledgement

The authors want to thank the Association for al-lowing them to present this history of wood pres-ervation research at FPL. The publication by CharlesA. Nelson “History of the U.S. Forest Products Lab-oratory (1910-1963)” was very helpful in establishingdates and places for the report. Our photographicstaff supplied all the personnel photos for this paper.


Discussion

W. S. MCNAMARA: Lee, I think you have done anexcellent job reminding the Association of the workthe Forest Products Laboratory had done for theAssociation and the work done serving industry ingeneral over the past seven decades. The questionI would like to ask, not so much to you Lee, but tothe Association in general, is what is going to happenover the next seven decades. We currently have anindustry group working through the National ForestProducts Association that reviews the programs inresearch on wood preservation and biodegradationat the laboratory. It is particularly important that wedo this at this time because of the entire thrust ofthe Federal budget is a reduction in governmentservices. We have just seen the services that havebeen provided by government to the wood preserv-ing industry. The positive services! I want to assuremembers that the Forest Service is responsive toindustry comments in directing priorities of the For-est Products Laboratory research in wood preser-vation. I ask members of the Association to use thisvehicle, to communicate their desires for researchthat is suggested to be performed at the laboratoryand also to protect things of interest to us, particu-larly the longterm test plots that we find so valuable.If we don’t continually make our case year by yearto do this, and keep our priorities well spelled outto the management of the Laboratory and the ForestService, we are going to loose contributions of theForest Products scientists. To participate in this com-mittee, simply slip me a business card while we areat the meeting, I’ll see you get the information as towhere and when the committee meets. It is usuallyone week around the fist of April in Madison. Itprovides you with an excellent chance to meet withthe scientists and learn firsthand what is going onthere and, most importantly, to provide industry in-put to support and assign priorities to the researchwork conducted at the Laboratory. I will appreciateany response of any member of the American Wood-Preservers’ Association. I assure you it is importantto keep wood preservation research alive and well.

MR. GJOVIK: Thank you, Bill. I would just like tosay that early on, the Forest Products Laboratorywas very responsive to industry requests and before1930 there were seven to ten members on Com-mittees of this Association and they responded torequests.

The Industry / Forest Products Laboratory inter-change of ideas and researchable problems is notsomething new. It has been a long-standing program;sometimes formal, sometimes informal. Currentbudget restraints may require certain research areasto be curtailed. What Bill says is true, and I urge youto join his committee and help out with the programreview.

W. C. KELSO JR.: Lee, I want to first congratulateyou on the excellent review of the history of theForest Products Laboratory. I want to make twocomments, they are not derogatory, but number oneI think you missed one important person—CatherineDuncan. The second comment is I want to congrat-ulate you of all the people you showed on the screenyou were the only one up to this date that has beenable to grow a beard.

MR. GJOVIK: Thank you, Bill, the omission of Cath-erine Duncan is an oversite and will be corrected.The beard is to cover up a bad case of the uglies.

DR. NICHOLAS: Our next speaker is Andy Baker.Andy is an engineer in the Energy and Chemicalsprogram at the U.S. Forest Products Lab in Madison.He has a degree in Chemical Engineering from theUniv. of Wisconsin and his current research interestsare in wood combustion, Wood Hydrolysis and Cor-rosion of Metals in contact with wood. He has beenworking on this program for the last 15 years. Histalk will be on Metal Corrosion in Treated Wood.Andy.

(Editors’ Note: Mr. Baker gave an interesting reviewof “Metal Corrosion in Treated Wood”).

Discussion

JOE M ORGAN : J. H. Baxter has test results onchemonite treated wood artificially wet wood in anaccelerated test and baths after 38 years in servicein Portland, Oregon. Our tests show initial rapid re-action with Zn galvanizing which slows as the am-monia evaporates and almost stops after a couple ofyears.

These bolts may look rusty, but tensile strengthtests show breaking strengths at or above the ratedstrengths.

Could you comment on this in light of your testresults.

MR. BAKER: I guess I can’t really comment toomuch on that because the exposure conditions areprobably much different. The corrosion rate wouldtend to decrease with time and the amount of de-crease depends on the exposure conditions. Couldyou say more about the exposure?

MR. MORGAN: We have one set of tests results inan artificial accelerated test for guardrail stockwhere we artificially wet the material on a daily basisfor about one hour. Also we have some test boltsthat were pulled out of some utility poles after 38years service which look fairly bad but they weretested for strength and all tested about 100 percent


of rated strength. I have plenty of information onthat if you would like to see it.

MR. BAKER The exposure you have is much dif-ferent from that I have. You have water washingover the surface of the guardrail, and the other wasjust exposed to weather. That is quite a bit differentfrom the exposure to soil burial and 100% Rh thatI used. I don’t think there is a serious problem withthe galvanized hardware on utility poles because inmost areas there are sufficient dry periods to inhibitthe corrosion. As you found, there was corrosion butnot enough to effect the bolt strength. It would havebeen better to test the complete bolted joint.

DR. NICHOLAS: Our next speaker, Bruce Johnson,is known to many of us having presented papers forthe Association in prior years. Bruce is a researchscientist at the U.S. Forest Products Lab in Madison.He has a BS degree in wood science and technologyfrom the U. of Mass. His MS and Ph.D. in woodscience are from the U. of Wis. in Madison. His cur-rent research interests include protection of woodin the marine environment. His first paper to AWPAin 1970 dealt with the effect of terrestrial microor-ganisms on the structure and permeability of wood.His topic today is Soft-Rot of Presevative-TreatedSouthern Pine in a Marine Environment. Bruce.

In: Proceedings of the 82d annual meetingof the American Wood-Preservers'Associat ion, vol . 82; 1986 April 27-30;P h i l a d e l p h i a . Stevensvil le, MD: AmericanWood-Preservers ' Association; 1986:133-149

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looking back at 75 years of research in wood … wood-preservers’ association133 1986 looking back...

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