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• 71. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1988

  The eighth annual report details continued progress on each of the five objectives. In this year's report, Objectives II and III from previous reports have been combined to reflect the similarity of each ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1988 Author: Morrell, Jeffrey J., Corden, M. E. (Malcolm E.) The eighth annual report details continued progress on each of the five objectives. In this year's report, Objectives II and III from previous reports have been combined to reflect the similarity of each effort. Improved fumigants: The previously established field trials continue to demonstrate the superior performance of both chioropicrin and Vorlex after 18 years in poles and 13 years in piling. In addition, solid methylisothiocyanate (MIT) continues to protect Douglas-fir poles in a manner similar to Vorlex. Along with evaluations of existing registered formulations, we continue to explore the use of novel solid fumigants for their ability to arrest decay in Douglas-fir heartwood. Laboratory studies indicate that both Mylone and sodium n-methyldithiocarbamate (NaMDC) can be pelletized to improve handling safety. Previous studies indicate that the rate of decomposition to produce MIT is often too slow for effective fungal control, but the incorporation of certain buffers or metallic salts can alter the rate and characteristics of chemical decomposition. In our tests, the levels of chemical release varied with PH; however, complete fungal control was not achieved. Further studies are underway to determine if other conditions can alter the rate of MIT production by these compounds. Both chemicals are registered for other, nonfood uses and should be registerable for application to wood. Efforts to better understand the properties of MIT, the major fungitoxic product of both Vorlex and Vapam, are also continuing. These efforts have led to the development of a preliminary model to describe fumigant movement through Douglas-fir heartwood. The goal of this work is optimize treatment dosage and application patterns for various pole sizes. In addition to the more theoretical studies, we are continuing our efforts to determine the ability of fumigants to control decay fungi in poles containing large decay voids and to determine the levels of volatile emissions from fumigant treated wood. Field treatment: The field tests to evaluate potential replacements for pentachlorophenol (penta) treatment of western redcedar sapwood were evaluated after 7 years using the Aspergillus bioassay. The results indicate that residual levels of chemical were detectable in the penta treatments, but the remaining test chemicals exhibited little evidence of residual fungitoxicity. Further decay tests are planned on material removed from these pole sections. In addition to the pole sections, the small-scale test blocks were also evaluated using the Aspergillus bioassay. The results indicate that several chemicals remained in the wood at fungitoxic levels after one year of accelerated weathering. Further decay tests are also planned on these samples. The bolt hole study is now in its seventh year and the incidence of decay fungi in the test poles remains low. Variations in incidence from year to year have made it difficult to draw any useful conclusions from this study. To overcome this problem, a second test has been established which accelerates leaching and evaluates the ability of a test fungus to invade the field drilled bolt hole to cause wood weight loss. Decay detection and residual strength: We continue to evaluate the use of lectins for detecting fungal colonization at the early stages. This past year, we completed a comparison of colonization by three common decay fungi over a 12 week period. The search for small-scale methods for estimating residual strength is also continuing. Longitudinal compression measurements were used to determine residual strength of a pole involved in an automobile accident. ii Finally, we have completed portions of a study to determine the effects of fungal colonization on wood strength. Four fungi, Poria carbonica, Poria placenta, Peniophora spp., and Haematostereum sanguinolentum were evaluated in this study. Results with P. carbonica and Peniophora spp. indicate strength effects lag behind fungal colony development in small beams. These results were similar to previous field studies and indicate that air-seasoning for 2 to 3 years should not produce significant strength losses. Further studies with these fungi are underway. Initiation of decay in air-seasoning Douglas-fir: While the air-seasoning studies are now completed, we are continuing to evaluate the data from these tests. A detailed examination of the three year decay development study indicates that several fungi were typically found only in the heartwood or sapwood zones of the pole sections. In addition, the fungal flora at the four seasoning sites varied widely, with the greatest deviation occurring at the Oroville, CA. This site has the driest and warmest conditions, and would appear to be best site for seasoning. A detailed discussion of isolation frequency by position is presented for the eleven most common basidiomycetes. Studies to prevent colonization by basidiomycetes during air-seasoning are also continuing using polyborate dips or sprays. Sodium octaborate tetrahydrate appears to reduce the level of colonization after one year of air-seasoning at both Oroville and Corvallis, OR. Dipping shortly after peeling appeared to produce the best results, although spraying at regular intervals also had some effect on colonization. This study will continue for an additional two years. Determining the ability of existing pressure treatment cycles to eliminate fungi which colonize Douglas-fir poles during air-seasoning also remains a high priority. Only a few additional schedules were examined during iv the past year, but efforts to develop more realistic heating curves are under way. In addition, several questions concerning the accuracy of the existing data were answered. Additional studies using the Cellon process and the longer steaming period for the ammoniacal copper zinc arsenate treatments are planned in the coming year. While sterilization during preservative treatment is an important factor in pole longevity, questions have also arisen concerning the storage of poles for long periods after treatment. A survey of poles which were treated with creosote, pentachiorophenol, chromated copper arsenate, and ammoniacal copper arsenate prior to storage for one to 15 years was conducted. While colonization varied widely between sites, the results indicated that storage of poles for long periods substantially increased the risk that the pole would be placed in service with an active decay fungus established somewhere along its length. Several suggestions are made for remedying this situation. Effect of microfunqi on Douglas-fir poles: A study was conducted to determine the effect of microfungi which commonly colonize fumigant treated Douglas-fir heartwood on the ability of P. carbonica and P. placenta to cause wood weight loss in fumigant treated wood. The results indicate that several isolates were associated with reduced weight losses by these fungi. The decreased weight losses suggest that the microfungi could be colonizing fumigant treated poles prior to the basidiomycetes and, once there, could help prevent reinvasion. This scheme may help explain the remarkable protection provided by fumigant treatment. Further studies are underway to explore this possibility. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1988 Author: Morrell, Jeffrey J., Corden, M. E. (Malcolm E.) The eighth annual report details continued progress on each of the five objectives. In this year's report, Objectives II and III from previous reports have been combined to reflect the similarity of each effort. Improved fumigants: The previously established field trials continue to demonstrate the superior performance of both chioropicrin and Vorlex after 18 years in poles and 13 years in piling. In addition, solid methylisothiocyanate (MIT) continues to protect Douglas-fir poles in a manner similar to Vorlex. Along with evaluations of existing registered formulations, we continue to explore the use of novel solid fumigants for their ability to arrest decay in Douglas-fir heartwood. Laboratory studies indicate that both Mylone and sodium n-methyldithiocarbamate (NaMDC) can be pelletized to improve handling safety. Previous studies indicate that the rate of decomposition to produce MIT is often too slow for effective fungal control, but the incorporation of certain buffers or metallic salts can alter the rate and characteristics of chemical decomposition. In our tests, the levels of chemical release varied with PH; however, complete fungal control was not achieved. Further studies are underway to determine if other conditions can alter the rate of MIT production by these compounds. Both chemicals are registered for other, nonfood uses and should be registerable for application to wood. Efforts to better understand the properties of MIT, the major fungitoxic product of both Vorlex and Vapam, are also continuing. These efforts have led to the development of a preliminary model to describe fumigant movement through Douglas-fir heartwood. The goal of this work is optimize treatment dosage and application patterns for various pole sizes. In addition to the more theoretical studies, we are continuing our efforts to determine the ability of fumigants to control decay fungi in poles containing large decay voids and to determine the levels of volatile emissions from fumigant treated wood. Field treatment: The field tests to evaluate potential replacements for pentachlorophenol (penta) treatment of western redcedar sapwood were evaluated after 7 years using the Aspergillus bioassay. The results indicate that residual levels of chemical were detectable in the penta treatments, but the remaining test chemicals exhibited little evidence of residual fungitoxicity. Further decay tests are planned on material removed from these pole sections. In addition to the pole sections, the small-scale test blocks were also evaluated using the Aspergillus bioassay. The results indicate that several chemicals remained in the wood at fungitoxic levels after one year of accelerated weathering. Further decay tests are also planned on these samples. The bolt hole study is now in its seventh year and the incidence of decay fungi in the test poles remains low. Variations in incidence from year to year have made it difficult to draw any useful conclusions from this study. To overcome this problem, a second test has been established which accelerates leaching and evaluates the ability of a test fungus to invade the field drilled bolt hole to cause wood weight loss. Decay detection and residual strength: We continue to evaluate the use of lectins for detecting fungal colonization at the early stages. This past year, we completed a comparison of colonization by three common decay fungi over a 12 week period. The search for small-scale methods for estimating residual strength is also continuing. Longitudinal compression measurements were used to determine residual strength of a pole involved in an automobile accident. ii Finally, we have completed portions of a study to determine the effects of fungal colonization on wood strength. Four fungi, Poria carbonica, Poria placenta, Peniophora spp., and Haematostereum sanguinolentum were evaluated in this study. Results with P. carbonica and Peniophora spp. indicate strength effects lag behind fungal colony development in small beams. These results were similar to previous field studies and indicate that air-seasoning for 2 to 3 years should not produce significant strength losses. Further studies with these fungi are underway. Initiation of decay in air-seasoning Douglas-fir: While the air-seasoning studies are now completed, we are continuing to evaluate the data from these tests. A detailed examination of the three year decay development study indicates that several fungi were typically found only in the heartwood or sapwood zones of the pole sections. In addition, the fungal flora at the four seasoning sites varied widely, with the greatest deviation occurring at the Oroville, CA. This site has the driest and warmest conditions, and would appear to be best site for seasoning. A detailed discussion of isolation frequency by position is presented for the eleven most common basidiomycetes. Studies to prevent colonization by basidiomycetes during air-seasoning are also continuing using polyborate dips or sprays. Sodium octaborate tetrahydrate appears to reduce the level of colonization after one year of air-seasoning at both Oroville and Corvallis, OR. Dipping shortly after peeling appeared to produce the best results, although spraying at regular intervals also had some effect on colonization. This study will continue for an additional two years. Determining the ability of existing pressure treatment cycles to eliminate fungi which colonize Douglas-fir poles during air-seasoning also remains a high priority. Only a few additional schedules were examined during iv the past year, but efforts to develop more realistic heating curves are under way. In addition, several questions concerning the accuracy of the existing data were answered. Additional studies using the Cellon process and the longer steaming period for the ammoniacal copper zinc arsenate treatments are planned in the coming year. While sterilization during preservative treatment is an important factor in pole longevity, questions have also arisen concerning the storage of poles for long periods after treatment. A survey of poles which were treated with creosote, pentachiorophenol, chromated copper arsenate, and ammoniacal copper arsenate prior to storage for one to 15 years was conducted. While colonization varied widely between sites, the results indicated that storage of poles for long periods substantially increased the risk that the pole would be placed in service with an active decay fungus established somewhere along its length. Several suggestions are made for remedying this situation. Effect of microfunqi on Douglas-fir poles: A study was conducted to determine the effect of microfungi which commonly colonize fumigant treated Douglas-fir heartwood on the ability of P. carbonica and P. placenta to cause wood weight loss in fumigant treated wood. The results indicate that several isolates were associated with reduced weight losses by these fungi. The decreased weight losses suggest that the microfungi could be colonizing fumigant treated poles prior to the basidiomycetes and, once there, could help prevent reinvasion. This scheme may help explain the remarkable protection provided by fumigant treatment. Further studies are underway to explore this possibility. Close

• 72. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1989

  Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1989 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication of Vapam 18 years after the initial application eliminated fungi which had recolonized the poles. Methylisothiocyanate (MITC) continues to protect Douglas-fir poles 12 years after application. Gelatin encapsulation of MITC or chioropicrin appears to have no negative influence on fungitoxicity of these chemicals. Application of water to decompose the gelatin accelerated initial chemical release, but had no longterm effects on performance. A series of laboratory trials have been established to evaluate the performance of sodium n-methyldithiocarbamate (NaMDC), the active ingredient of Vapam. This chemical decomposes more slowly than the liquid formulations and a number of additives are being evaluated to accelerated decomposition. Along with the solid NaMDC, a pelletized formulation of Vapam was evaluated which contained 15 or 40 % NaMDC. These evaluations indicated that the addition of water accelerates release, but the fungal survival in these tests was more variable. The results suggest that a dosage 2 times greater than the liquid formulation is required for effective fungal control; however, further tests are planned to confirm these results. The evaluations of MITC-FUME in Douglas-fir and southern pine poles indicated that MITC has moved to a greater extent in Douglas-fir. Both closed tube bioassays and gas chromatographic analyses of ethyl acetate extracts of wood samples indicated that MITC was present at higher levels in Douglas-fir poles. Southern pine is far more permeable than Douglas-fir and MITC movement should be more rapid in this species. Further tests are planned to identify the nature of this delayed movement. 11 Evaluations of Dazomet, a crystalline solid which decomposes tO produce MITC in wood, indicate that detectable levels of this chemical are present in virtually all of the treatment groups. The decomposition rate of this chemical is normally too slow for effective fungal control and these trials are examining the ability of various additives to accelerate decomposition. Further evaluations of pole sections treated with Dazomet and selected additives are underway. A study to evaluate the effect of voids on fumigant effectivness suggests that voids do not adversely affect MITC movement through Douglas-fir pole sections. These results indicate that treatment of voids should be costeffective if the chemical is not applied directly to the void and if the pole retains a sufficient degree of strength. We continue to develop and refine a model for simulating the movement of MITC through Douglas-fir under varying temperature and moisture conditions. The model has been improved to permit three dimensional evaluations, but the times required for computation are still somewhat long. Further evaluations using a variety of environmental conditions are planned. Evaluations of potential replacements for pentachiorophenol for treatment of western redcedar sapwood and field drilled bolt holes have identified several promising alternatives. These chemicals are now under study in several modified field and laboratory tests. Field trials of several potential treatments for field drilled bolt holes indicate that Boracol 40, disodium octaborate tetrahydrate and ammonium bifluoride provided excellent protection over an 8 year period. These formulations all are relatively safe and can be easily applied in the field. 111 A laboratory trial to evaluate the effects of selected basidiomycetes on strength of Douglas-fir sapwood and heartwood has concluded. Fungal density, measured as the average number of fungi colonies per beam, gradually increased in all of the beams while longitudinal compression strength (LCS), modulus of rupture (MOR), and modulus of elesticity (MOE) slowly declined. Of the measurements, LCS appeared to be most useful, probably owing to the increased number of sampling sites per beam. The results indicate that the degree of colonization was not a good indicator of wood strength effects. The value of kerfing for decreasing post-treatment checking and improving the service life of Douglas-fir poles was evaluated using a series of inspection reports from a local utility. Kerfed transmission poles had substantially lower rates of internal decay and rejection, but there appeared to be little difference in the rate of decay between kerfed and non-kerfed distribution poles. The evaluation of disodium octaborate tetrahydrate for preventing colonization of air-seasoning Douglas-fir pole sections has been completed. Spraying with a 10 % boric acid equivalent solution (BAE) at 6 month intervals provided the greatest degree of protection, although dipping in a 20 % BAE solution at the start of air-seasoning produced a similar degree of protection. As expected, fungal colonization was far lower at the dryer Oroville site and borate treatment had little influence on the degree of fungal colonization at this site. The results indicate that borate treatment at the start of airseasoning is a viable method for limiting fungal colonization in moist airseasoning sites west of the Cascade Mountains. Evaluations of the tolerance of Stereum sanguinolentum and Peniophora spp. to elevated temperature exposures indicated that both of these fungi were extremely sensitive to elevated temperatures. The lack of long-term survival structures in these fungi probably accounts for this susceptibility to heat. iv A series of trials which measured internal temperatures in Douglas-fir pole sections during treatment with ammoniacal copper arsenate were used to develop a model for predicting internal heating during steaming. The results indicated that previous heating curves were overly optimistic in their prediction of heating. A series of heating curves for various pole diameters and starting conditions are presented. A number of externally applied groundline treatments are under evaluation in a field trial at Peavy Arboretum and a second trial will be established in the San Francisco Bay area. Seven formulations (including standards) are included. The Peavy site will be sampled in the next few months. The performance of copper naphthenate in western wood species is being evaluated in a series of small western redcedar sapwood stakelets which have been treated to a range of retentions and exposed in the fungus cellar. The results will be used to help confirm the performance of copper naphthenate in this species. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1989 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication of Vapam 18 years after the initial application eliminated fungi which had recolonized the poles. Methylisothiocyanate (MITC) continues to protect Douglas-fir poles 12 years after application. Gelatin encapsulation of MITC or chioropicrin appears to have no negative influence on fungitoxicity of these chemicals. Application of water to decompose the gelatin accelerated initial chemical release, but had no longterm effects on performance. A series of laboratory trials have been established to evaluate the performance of sodium n-methyldithiocarbamate (NaMDC), the active ingredient of Vapam. This chemical decomposes more slowly than the liquid formulations and a number of additives are being evaluated to accelerated decomposition. Along with the solid NaMDC, a pelletized formulation of Vapam was evaluated which contained 15 or 40 % NaMDC. These evaluations indicated that the addition of water accelerates release, but the fungal survival in these tests was more variable. The results suggest that a dosage 2 times greater than the liquid formulation is required for effective fungal control; however, further tests are planned to confirm these results. The evaluations of MITC-FUME in Douglas-fir and southern pine poles indicated that MITC has moved to a greater extent in Douglas-fir. Both closed tube bioassays and gas chromatographic analyses of ethyl acetate extracts of wood samples indicated that MITC was present at higher levels in Douglas-fir poles. Southern pine is far more permeable than Douglas-fir and MITC movement should be more rapid in this species. Further tests are planned to identify the nature of this delayed movement. 11 Evaluations of Dazomet, a crystalline solid which decomposes tO produce MITC in wood, indicate that detectable levels of this chemical are present in virtually all of the treatment groups. The decomposition rate of this chemical is normally too slow for effective fungal control and these trials are examining the ability of various additives to accelerate decomposition. Further evaluations of pole sections treated with Dazomet and selected additives are underway. A study to evaluate the effect of voids on fumigant effectivness suggests that voids do not adversely affect MITC movement through Douglas-fir pole sections. These results indicate that treatment of voids should be costeffective if the chemical is not applied directly to the void and if the pole retains a sufficient degree of strength. We continue to develop and refine a model for simulating the movement of MITC through Douglas-fir under varying temperature and moisture conditions. The model has been improved to permit three dimensional evaluations, but the times required for computation are still somewhat long. Further evaluations using a variety of environmental conditions are planned. Evaluations of potential replacements for pentachiorophenol for treatment of western redcedar sapwood and field drilled bolt holes have identified several promising alternatives. These chemicals are now under study in several modified field and laboratory tests. Field trials of several potential treatments for field drilled bolt holes indicate that Boracol 40, disodium octaborate tetrahydrate and ammonium bifluoride provided excellent protection over an 8 year period. These formulations all are relatively safe and can be easily applied in the field. 111 A laboratory trial to evaluate the effects of selected basidiomycetes on strength of Douglas-fir sapwood and heartwood has concluded. Fungal density, measured as the average number of fungi colonies per beam, gradually increased in all of the beams while longitudinal compression strength (LCS), modulus of rupture (MOR), and modulus of elesticity (MOE) slowly declined. Of the measurements, LCS appeared to be most useful, probably owing to the increased number of sampling sites per beam. The results indicate that the degree of colonization was not a good indicator of wood strength effects. The value of kerfing for decreasing post-treatment checking and improving the service life of Douglas-fir poles was evaluated using a series of inspection reports from a local utility. Kerfed transmission poles had substantially lower rates of internal decay and rejection, but there appeared to be little difference in the rate of decay between kerfed and non-kerfed distribution poles. The evaluation of disodium octaborate tetrahydrate for preventing colonization of air-seasoning Douglas-fir pole sections has been completed. Spraying with a 10 % boric acid equivalent solution (BAE) at 6 month intervals provided the greatest degree of protection, although dipping in a 20 % BAE solution at the start of air-seasoning produced a similar degree of protection. As expected, fungal colonization was far lower at the dryer Oroville site and borate treatment had little influence on the degree of fungal colonization at this site. The results indicate that borate treatment at the start of airseasoning is a viable method for limiting fungal colonization in moist airseasoning sites west of the Cascade Mountains. Evaluations of the tolerance of Stereum sanguinolentum and Peniophora spp. to elevated temperature exposures indicated that both of these fungi were extremely sensitive to elevated temperatures. The lack of long-term survival structures in these fungi probably accounts for this susceptibility to heat. iv A series of trials which measured internal temperatures in Douglas-fir pole sections during treatment with ammoniacal copper arsenate were used to develop a model for predicting internal heating during steaming. The results indicated that previous heating curves were overly optimistic in their prediction of heating. A series of heating curves for various pole diameters and starting conditions are presented. A number of externally applied groundline treatments are under evaluation in a field trial at Peavy Arboretum and a second trial will be established in the San Francisco Bay area. Seven formulations (including standards) are included. The Peavy site will be sampled in the next few months. The performance of copper naphthenate in western wood species is being evaluated in a series of small western redcedar sapwood stakelets which have been treated to a range of retentions and exposed in the fungus cellar. The results will be used to help confirm the performance of copper naphthenate in this species. Close

• 73. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1993

  Evaluation of previously established field trials of internal remedial treatments continues to verify the excellent long-term protection afforded by these treatments. Field trials with gell encapsulated methylisothiocyanate ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1993 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluation of previously established field trials of internal remedial treatments continues to verify the excellent long-term protection afforded by these treatments. Field trials with gell encapsulated methylisothiocyanate (MITC) demonstrate that gelatin does not interfere with chemical release, nor is addition of supplemental moisture required for release. Field trials have been established to evaluate several new formulations including Basamid plus copper, boron/fluoride rods, and boron rods. Field trials of gelled and pelletized metham sodium indicate that both formulations are moving well through Douglas-fir poles one year after treatment. Evaluations of a copper naphthenate/boron paste for internal treatment indicate that the formulation has moved a short distance from the point of application 3 years after treatment. Boron rod field trials were not fully sampled for residual chemical level this past year; however, evaluation of cores removed from fused borate rod trials in New York indicate that some additional boron diffusion has occurred. Examination of treatment holes suggests that considerable amounts of the boron remain in rod form 2 years after application. In laboratory studies, we have evaluated the use of metham sodium/basamid mixtures and have found that these formulations provide enhanced MITC production over longer periods than either of the components alone. Both formulations were solid, creating the potential for development of safer formulations which provide a rapid release with long term protection. Field trials of these systems will be established in the coming months. Studies also continue with Basamid in an effort to enhance decomposition of this compound. Studies have shown that moisture addition has the most significant effect on decomposition followed by the presence of copper and increasing pH. Further studies on decomposition products are planned to better understand the activity of this molecule. Examination of Douglas-fir timbers treated with metham sodium indicate that MITC levels are similar to those found in poles at similar times after treatment. The presence increased surface area on timbers apparently did not adversely affect diffusion or chemical loss. Evaluation of the fungitoxicity of mixtures of MITC and carbon disulfide is underway in an effort better understand the activity of metham sodium. This compound decomposes to produce a wide array of volatile compounds with varying degrees of toxicity to fungi. Preliminary trials have shown the relatively low toxicity associated with carbon disulfide, a major decomposition product, particularly under acidic conditions. Trials with mixtures will begin shortly. Efforts to develop a three dimensional model of MITC movement are continuing. The model has been evaluated on data collected from small blocks and efforts are underway to verify these results. In addition, full pole grids have been prepared to evaluate the effects of treatment hole geometry and orientation on fumigant movement. Studies to identify alternative treatments for protecting western redcedar sapwood from decay are continuing. A variety chemicals have been shown to be effective 5 years after treatment; however, longer term trials of other formulations suggests that performance declines rapidly at longer time points. Field trials of remedial treatments for field drilled bolt holes continue to demonstrate the performance of diffusible boron and fluoride for preventing fungal attack. These trials will be evaluated again in the coming year. Inspection of the above ground region of Douglas-fir poles in the Pacific Northwest have shown that many poles are colonized by decay fungi far above the groundline. Fungal incidence was greatest in poles near the coast, but decay fungi were also isolated from poles in drier climates. Sampling of additional poles is planned to provide a more detailed analysis of the risk of above ground decay in this region. Efforts are also continuing to evaluate the performance of through-bored Douglas-fir poles to provide better data on the degree of preservative penetration required in the through-bored zone to achieve optimum performance. These trials have shown that most poles are well treated, but no decay has been detected in the through bored zone of poles with as little as 60 % of the through-bored zone treated. Efforts are also underway to evaluate penetration and retention of preservative in poles with various throughboring patterns. Studies to identify optimum conditions for sterilization of air-seasoned Douglas-fir poles are continuing. These trials have evaluated pentachlorophenol in oil treatments. The results illustrate the value of long treatment cycles which incorporate Boulton-seasoning. The data from these trials will be used to construct heating curves for this treatment. Trials of groundline preservative systems on Douglas-fir pole stubs continue to show that more recently developed formulations continue to move through the wood at rates which are similar to those found with older pentachlorophenol based systems. Trials in California on pine, Douglas-fir and western redcedar have provided similar results. Tests are now underway to establish thresholds for mixtures of groundline preservative formulations. Copper naphthenate treated wood continues to perform well in both field and fungal cellar trials. Unweathered western redcedar stakes have tended to perform better than stakes which were weathered prior to treatment. These differences may reflect an increased permeability which enhances leaching. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1993 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluation of previously established field trials of internal remedial treatments continues to verify the excellent long-term protection afforded by these treatments. Field trials with gell encapsulated methylisothiocyanate (MITC) demonstrate that gelatin does not interfere with chemical release, nor is addition of supplemental moisture required for release. Field trials have been established to evaluate several new formulations including Basamid plus copper, boron/fluoride rods, and boron rods. Field trials of gelled and pelletized metham sodium indicate that both formulations are moving well through Douglas-fir poles one year after treatment. Evaluations of a copper naphthenate/boron paste for internal treatment indicate that the formulation has moved a short distance from the point of application 3 years after treatment. Boron rod field trials were not fully sampled for residual chemical level this past year; however, evaluation of cores removed from fused borate rod trials in New York indicate that some additional boron diffusion has occurred. Examination of treatment holes suggests that considerable amounts of the boron remain in rod form 2 years after application. In laboratory studies, we have evaluated the use of metham sodium/basamid mixtures and have found that these formulations provide enhanced MITC production over longer periods than either of the components alone. Both formulations were solid, creating the potential for development of safer formulations which provide a rapid release with long term protection. Field trials of these systems will be established in the coming months. Studies also continue with Basamid in an effort to enhance decomposition of this compound. Studies have shown that moisture addition has the most significant effect on decomposition followed by the presence of copper and increasing pH. Further studies on decomposition products are planned to better understand the activity of this molecule. Examination of Douglas-fir timbers treated with metham sodium indicate that MITC levels are similar to those found in poles at similar times after treatment. The presence increased surface area on timbers apparently did not adversely affect diffusion or chemical loss. Evaluation of the fungitoxicity of mixtures of MITC and carbon disulfide is underway in an effort better understand the activity of metham sodium. This compound decomposes to produce a wide array of volatile compounds with varying degrees of toxicity to fungi. Preliminary trials have shown the relatively low toxicity associated with carbon disulfide, a major decomposition product, particularly under acidic conditions. Trials with mixtures will begin shortly. Efforts to develop a three dimensional model of MITC movement are continuing. The model has been evaluated on data collected from small blocks and efforts are underway to verify these results. In addition, full pole grids have been prepared to evaluate the effects of treatment hole geometry and orientation on fumigant movement. Studies to identify alternative treatments for protecting western redcedar sapwood from decay are continuing. A variety chemicals have been shown to be effective 5 years after treatment; however, longer term trials of other formulations suggests that performance declines rapidly at longer time points. Field trials of remedial treatments for field drilled bolt holes continue to demonstrate the performance of diffusible boron and fluoride for preventing fungal attack. These trials will be evaluated again in the coming year. Inspection of the above ground region of Douglas-fir poles in the Pacific Northwest have shown that many poles are colonized by decay fungi far above the groundline. Fungal incidence was greatest in poles near the coast, but decay fungi were also isolated from poles in drier climates. Sampling of additional poles is planned to provide a more detailed analysis of the risk of above ground decay in this region. Efforts are also continuing to evaluate the performance of through-bored Douglas-fir poles to provide better data on the degree of preservative penetration required in the through-bored zone to achieve optimum performance. These trials have shown that most poles are well treated, but no decay has been detected in the through bored zone of poles with as little as 60 % of the through-bored zone treated. Efforts are also underway to evaluate penetration and retention of preservative in poles with various throughboring patterns. Studies to identify optimum conditions for sterilization of air-seasoned Douglas-fir poles are continuing. These trials have evaluated pentachlorophenol in oil treatments. The results illustrate the value of long treatment cycles which incorporate Boulton-seasoning. The data from these trials will be used to construct heating curves for this treatment. Trials of groundline preservative systems on Douglas-fir pole stubs continue to show that more recently developed formulations continue to move through the wood at rates which are similar to those found with older pentachlorophenol based systems. Trials in California on pine, Douglas-fir and western redcedar have provided similar results. Tests are now underway to establish thresholds for mixtures of groundline preservative formulations. Copper naphthenate treated wood continues to perform well in both field and fungal cellar trials. Unweathered western redcedar stakes have tended to perform better than stakes which were weathered prior to treatment. These differences may reflect an increased permeability which enhances leaching. Close

• 74. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; October 1996

  The Cooperative continues to actively address a diverse array of issues related to the effective use of wood utility poles. The trials to evaluate the effectiveness of MITC-Fume are now in their seventh ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; October 1996 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) The Cooperative continues to actively address a diverse array of issues related to the effective use of wood utility poles. The trials to evaluate the effectiveness of MITC-Fume are now in their seventh year and continue to show that methylisothiocyanate (MITC) levels in MITC-Fume treatments remain higher than comparable metham sodium treatments. The levels of chemical are, however, declining, suggesting that this treatment may need replenishment in 3 to 5 years. Trials with the solid wood fumigant Basamid continue to show that MITC release can be enhanced by addition of small amounts of copper. Field trials suggest that these additives become less important with time. As a result, unamended Basamid may be suitable for treatment where the risk of immediate decay is not high, but the utility wishes to protect against future attack. Field trials with various water-diffusible internal treatments continue to show that these treatments move more slowly through Douglas-fir heartwood than do fumigants. Boron levels in pole sections treated with fused borate rods remain at levels that will protect against fungal attack 6 years after treatment. Similar trials with a boron/ fluoride rod indicate that neither fluoride or boron levels in the poles are adequate for wood protection 2 years after treatment. While the dosages tested were relatively low, the volumes of chemical were similar to the liquid volumes normally applied during internal remedial treatment. We will sample these poles next year to ensure that our measurements accurately reflect the chemical levels present. Trials to evaluate the effects of glycol on boron movement from fused borate rods suggest that glycol enhanced boron diffusion to only a slight extent. This effect was most pronounced at lower moisture contents. This trial was established to identify methods for improving boron movement in drier wood. In addition, moisture measurements in these poles suggest the internal wood moisture content varies widely both seasonally and positionally. While elevated moisture levels can negatively affect the movement of gaseous fumigants, excess moisture is critical for diffusion of boron or fluoride and its absence around the treatment site can markedly reduce the efficacy of rod treatments. These poles will continue to be monitored to assess both boron movement and seasonal changes in moisture content. Trials to identify safe, effective and easily used systems for protecting wood exposed during field fabrication are continuing. Boron and fluoride continue to provide excellent protection to field drilled bolt holes. These treatments are safe and easy to apply, and have provided protection in our field test for 14 years. Trials of similar formulations on simulated decking are also reported to provide additional information on the ability of boron and fluoride to protect exposed Douglas-fir heartwood. Efforts to improve the effectiveness of through boring as a method for enhancing the treatment of Douglas-fir poles are continuing. This past year, we evaluated preservative distribution around through bored holes as a means of developing optimum through boring patterns that maximized treatment while minimizing potential strength effects. These trials suggest the diamond shaped through boring zone of effect is relatively narrow. This information will be used in the coming year to construct optimum patterns for poles of various classes. The goal of this project is to develop a standard through boring pattern that would permit automation of the process. This would create the potential for cost savings on new poles. Trials to evaluate the durability of western redcedar are nearly complete. These trials were initiated because of concerns that second growth western redcedar might be less durable than poles cut from older trees. As expected, cedar varied widely in its resistance to fungal attack. This resistance, however, was not related to tree age, suggesting that there might not be a difference between so-called "old-growth" and "second growth" material. These data will be more thoroughly analyzed once the final set of trials are completed. In addition, we are evaluating more rapid methods for assessing cedar durability by measuring tropolone content. Tropolones are an important component of the extractives that make cedar heartwood so durable. Field trials of various externally applied supplemental groundline treatments are continuing at sites in Oregon, California, and New York. Trials in Corvallis, Oregon, have shown that various copper naphthenate, fluoride or boron based systems are at least as effective as the pentachlorophenol (penta) based systems that were formerly used for this purpose. Penta concentrations in one system have now declined below a protective level, while the copper based systems continue to remain at a protective level. Field trials in California are following similar trends and indicate that the alternative systems will provide comparable performance. Fungus cellar trials of copper naphthenate treated western redcedar stakes continue to show that this chemical provides excellent protection to cedar sapwood. Weathered wood that was treated with copper naphthenate continues to perform more poorly than freshly sawn wood treated to similar retention levels. Variations in permeability likely account for these differences. A new Wood Pole Maintenance Manual has been completed and is now ready for distribution. This update of the 1979 publication includes more information on initial pole procurement and closely follows the video by the same name that we produced in 1994. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; October 1996 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) The Cooperative continues to actively address a diverse array of issues related to the effective use of wood utility poles. The trials to evaluate the effectiveness of MITC-Fume are now in their seventh year and continue to show that methylisothiocyanate (MITC) levels in MITC-Fume treatments remain higher than comparable metham sodium treatments. The levels of chemical are, however, declining, suggesting that this treatment may need replenishment in 3 to 5 years. Trials with the solid wood fumigant Basamid continue to show that MITC release can be enhanced by addition of small amounts of copper. Field trials suggest that these additives become less important with time. As a result, unamended Basamid may be suitable for treatment where the risk of immediate decay is not high, but the utility wishes to protect against future attack. Field trials with various water-diffusible internal treatments continue to show that these treatments move more slowly through Douglas-fir heartwood than do fumigants. Boron levels in pole sections treated with fused borate rods remain at levels that will protect against fungal attack 6 years after treatment. Similar trials with a boron/ fluoride rod indicate that neither fluoride or boron levels in the poles are adequate for wood protection 2 years after treatment. While the dosages tested were relatively low, the volumes of chemical were similar to the liquid volumes normally applied during internal remedial treatment. We will sample these poles next year to ensure that our measurements accurately reflect the chemical levels present. Trials to evaluate the effects of glycol on boron movement from fused borate rods suggest that glycol enhanced boron diffusion to only a slight extent. This effect was most pronounced at lower moisture contents. This trial was established to identify methods for improving boron movement in drier wood. In addition, moisture measurements in these poles suggest the internal wood moisture content varies widely both seasonally and positionally. While elevated moisture levels can negatively affect the movement of gaseous fumigants, excess moisture is critical for diffusion of boron or fluoride and its absence around the treatment site can markedly reduce the efficacy of rod treatments. These poles will continue to be monitored to assess both boron movement and seasonal changes in moisture content. Trials to identify safe, effective and easily used systems for protecting wood exposed during field fabrication are continuing. Boron and fluoride continue to provide excellent protection to field drilled bolt holes. These treatments are safe and easy to apply, and have provided protection in our field test for 14 years. Trials of similar formulations on simulated decking are also reported to provide additional information on the ability of boron and fluoride to protect exposed Douglas-fir heartwood. Efforts to improve the effectiveness of through boring as a method for enhancing the treatment of Douglas-fir poles are continuing. This past year, we evaluated preservative distribution around through bored holes as a means of developing optimum through boring patterns that maximized treatment while minimizing potential strength effects. These trials suggest the diamond shaped through boring zone of effect is relatively narrow. This information will be used in the coming year to construct optimum patterns for poles of various classes. The goal of this project is to develop a standard through boring pattern that would permit automation of the process. This would create the potential for cost savings on new poles. Trials to evaluate the durability of western redcedar are nearly complete. These trials were initiated because of concerns that second growth western redcedar might be less durable than poles cut from older trees. As expected, cedar varied widely in its resistance to fungal attack. This resistance, however, was not related to tree age, suggesting that there might not be a difference between so-called "old-growth" and "second growth" material. These data will be more thoroughly analyzed once the final set of trials are completed. In addition, we are evaluating more rapid methods for assessing cedar durability by measuring tropolone content. Tropolones are an important component of the extractives that make cedar heartwood so durable. Field trials of various externally applied supplemental groundline treatments are continuing at sites in Oregon, California, and New York. Trials in Corvallis, Oregon, have shown that various copper naphthenate, fluoride or boron based systems are at least as effective as the pentachlorophenol (penta) based systems that were formerly used for this purpose. Penta concentrations in one system have now declined below a protective level, while the copper based systems continue to remain at a protective level. Field trials in California are following similar trends and indicate that the alternative systems will provide comparable performance. Fungus cellar trials of copper naphthenate treated western redcedar stakes continue to show that this chemical provides excellent protection to cedar sapwood. Weathered wood that was treated with copper naphthenate continues to perform more poorly than freshly sawn wood treated to similar retention levels. Variations in permeability likely account for these differences. A new Wood Pole Maintenance Manual has been completed and is now ready for distribution. This update of the 1979 publication includes more information on initial pole procurement and closely follows the video by the same name that we produced in 1994. Close

• 75. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1987

  This seventh annual report outlines our continued progress on each of six objectives. Improved fumigants: We continue to evaluate previously established field tests, which inlicate that chioropicrin continues ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1987 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) This seventh annual report outlines our continued progress on each of six objectives. Improved fumigants: We continue to evaluate previously established field tests, which inlicate that chioropicrin continues to protect Douglas-fir poles after 17 years and piling after 12 years. Vorlex treated poles are being gradually recolonized by decay fungi, while the Vapam treated poles appear to have little resistance to decay fungi. The latter poles were retreated last summer and will be used to determine the effectiveness of fumigant retreatment. Solid methylisothiocyanate (NIT) continues to protect Douglasfir poles, although the 20 percent NIT treatment has experienced slightly higher levels of colonization after 9 years. Additional tests to evaluate the effectiveness of gelatin encapsulated MIT or chioropicrin indicate that both chemicals continue to remain effective. In addition, there now appears to be little difference between the levels of control exhibited following addition of varying amounts of water to the poles along with gelatin encapsulated NIT. Closed tube bioassays indicate the chioropicrin remains at fungitoxic levels after 17 years, while no volatile fungitoxins appear to be present in Vapam or Vorlex treated wood. The evaluation of untreated Douglas-fir posts treated with NIT, chloropicrin, or Vapam indicate that fumigants can not ccatletely protect untreated wood in ground contact unless there is sane other type of preservative treated barrier present. Although the NIT treatment provided the best protection, all of the posts experienced some surface decay and termite attack after 10 years. These results appear similar to those found with more recent tests of posts treated with various coLthinations of preservative containing wraps and fuinigants. Evaluation of Mylone and tridipain, two solid chemicals that degrade to produce NIT, initcates that NIT production and fungal control are enhanced by the addition of basic pH buffers; however, only the pH 12 buffer resulted in rapid fungal control. These results Jnitcate that the rate of fumigant release can be tailored to control specific decay problems. We have also investigated the decomposition of Vapam in wood. As previously reported, there are over 14 potential deccmposition products from this chemical. This past year we developed methods for assaying these chemicals, evaluated the long-term stability of each, and prepared test blocks for evaluating decc*,osjtion in wood. In addition, we have studied the migration of volatile compounds from Vapam and NIT treated blocks under controlled aeration. After 5,000 hours, detectable levesis of NIT, carbon disulfide, and carbon oxysulfide are still present in air surrounding the Douglas-fir blocks. These tests indicate that low levels of volatile chemicals are continuously eninitted from fumigant treated wood. While this poses little difficulty for utility poles, it may pose some hazard for wood in closed spaces. Evaluations will continue until the emission levels decline below detectable limits. In addition to Vapam deccmposition studies, we have also evaluated the decoxrosition, movement and fungitoxicity of NIT under a variety of environmental conditions. In general, wet wood held less NIT, but the degree of control produced was more rapid. These results suggest that dry wood will act as a reseivoir of NIT, which will be released as moisture enters and swells the wood. This effect may provide an excellent long-term decay control strategy. The information from these studies will be used to develop more 111 ecific recaimrndations for fumigant treatment. Cedar Saood Decay Control: This past year we reestablished the field test of promising nei pentachiorophenol replacements, incorporating 26 chemicals into these tests. These saitles will be evaluated after 1 and 2 years to determine efficacy. In addition to the field test, we evaluated 13 new formulations or cinations of formulations in our laboratory screening tests. A nuner of chemicals including Isothiazolone, Amical 48 and a nurrer of quaternary aimnonium compounds appear promising and have been included in the field test. Bolt Hole Decay Prevention: Test established 5 years ago to determine the effectiveness of sprays, liquids or pastes applied to field drilled bolts holes indicate that airanonium bifluoride, Boracol 40, and 10% penta provided greater protection than Polybor or Patox washers. In addition, no evidence of corrosion was associated with any of the treatments. Fumigant treatments below the bolt holes continue to eliminate decay fungi, although samples removed from further down the pole indicate an incoIr)1ete distribution of MIT. These tests will be reevaluated this coming year. Detecting Early Decay and Estimating Residual Strength: We continue to evaluate the use of fluorescent coupled lectins and infra-red spectroscopy for detecting fungi in wood and early decay under controlled laboratory conditions. We have also continued evaluation of longitudinal compression (L) as a measure of ultite wood strength using a series of 27 Ldgepole pine posts. While the dense knot clusters interferred with the analysis, LCS, in combination with other parameters, was a reasonably good predictor of bending strength. These tests will continue with more uniform material. iv In addition to tests of LCS, we have evaluated the ability of small scal e tests to determine the strength of various wood pole connectors. Out results were in close agreement with those obtained using full scale tests aii illustrate the value of using small r1 e tests to develop strength information. Initiation of Decay in Air-Seasoning Douglas-fir: We continue to evaluate the data developed in the air-seasoning st1wies. This past year we began to develop information on the effects of various colony sizes on wood strength. This data will help us assign strength values to the colony size data we ha developed frau the air-seasoning study. At present, only Peniophora spp. has been tested, but . carbonica, P. placenta, and Haematostereum sanguinolentuin will also be included. Evaluation of the teinperatures required to eliminate fungi from Douglas-f ir poles also continue. We have ccatpleted 9 test charges which indicate that the penta treatmants involving a Boulton-seasoning cycle result in a ixre than adequate heating of the wood, while steam treants associated with amnniacal copper arsenate are nre variable. We feel that longer heating periods are required for poles greater than 12 inches in diamater, but that the current 6 hour steam period will result in heating of the center to 67 C for over 1 hour in smaller poles. Microfungi in Douglas-fir Poles: We continue to evaluate the effects of nticrofungi on properties of fumigant treated Douglas-fir poles. These tests indicate that prior colonization of fumigant treated wood by Scytalidium or Trichoderma species resulted in lower weight losses by P. placenta and . carbonica. Evaluation of a Cellon treated Douglas-fir laminated beam indicated that V severe penta depletion was associated with virtually all of the surface decay present. This beam had only been in service for 12 years in an extremely dry climate arxl it is unclear why the decay was so rapid. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1987 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) This seventh annual report outlines our continued progress on each of six objectives. Improved fumigants: We continue to evaluate previously established field tests, which inlicate that chioropicrin continues to protect Douglas-fir poles after 17 years and piling after 12 years. Vorlex treated poles are being gradually recolonized by decay fungi, while the Vapam treated poles appear to have little resistance to decay fungi. The latter poles were retreated last summer and will be used to determine the effectiveness of fumigant retreatment. Solid methylisothiocyanate (NIT) continues to protect Douglasfir poles, although the 20 percent NIT treatment has experienced slightly higher levels of colonization after 9 years. Additional tests to evaluate the effectiveness of gelatin encapsulated MIT or chioropicrin indicate that both chemicals continue to remain effective. In addition, there now appears to be little difference between the levels of control exhibited following addition of varying amounts of water to the poles along with gelatin encapsulated NIT. Closed tube bioassays indicate the chioropicrin remains at fungitoxic levels after 17 years, while no volatile fungitoxins appear to be present in Vapam or Vorlex treated wood. The evaluation of untreated Douglas-fir posts treated with NIT, chloropicrin, or Vapam indicate that fumigants can not ccatletely protect untreated wood in ground contact unless there is sane other type of preservative treated barrier present. Although the NIT treatment provided the best protection, all of the posts experienced some surface decay and termite attack after 10 years. These results appear similar to those found with more recent tests of posts treated with various coLthinations of preservative containing wraps and fuinigants. Evaluation of Mylone and tridipain, two solid chemicals that degrade to produce NIT, initcates that NIT production and fungal control are enhanced by the addition of basic pH buffers; however, only the pH 12 buffer resulted in rapid fungal control. These results Jnitcate that the rate of fumigant release can be tailored to control specific decay problems. We have also investigated the decomposition of Vapam in wood. As previously reported, there are over 14 potential deccmposition products from this chemical. This past year we developed methods for assaying these chemicals, evaluated the long-term stability of each, and prepared test blocks for evaluating decc*,osjtion in wood. In addition, we have studied the migration of volatile compounds from Vapam and NIT treated blocks under controlled aeration. After 5,000 hours, detectable levesis of NIT, carbon disulfide, and carbon oxysulfide are still present in air surrounding the Douglas-fir blocks. These tests indicate that low levels of volatile chemicals are continuously eninitted from fumigant treated wood. While this poses little difficulty for utility poles, it may pose some hazard for wood in closed spaces. Evaluations will continue until the emission levels decline below detectable limits. In addition to Vapam deccmposition studies, we have also evaluated the decoxrosition, movement and fungitoxicity of NIT under a variety of environmental conditions. In general, wet wood held less NIT, but the degree of control produced was more rapid. These results suggest that dry wood will act as a reseivoir of NIT, which will be released as moisture enters and swells the wood. This effect may provide an excellent long-term decay control strategy. The information from these studies will be used to develop more 111 ecific recaimrndations for fumigant treatment. Cedar Saood Decay Control: This past year we reestablished the field test of promising nei pentachiorophenol replacements, incorporating 26 chemicals into these tests. These saitles will be evaluated after 1 and 2 years to determine efficacy. In addition to the field test, we evaluated 13 new formulations or cinations of formulations in our laboratory screening tests. A nuner of chemicals including Isothiazolone, Amical 48 and a nurrer of quaternary aimnonium compounds appear promising and have been included in the field test. Bolt Hole Decay Prevention: Test established 5 years ago to determine the effectiveness of sprays, liquids or pastes applied to field drilled bolts holes indicate that airanonium bifluoride, Boracol 40, and 10% penta provided greater protection than Polybor or Patox washers. In addition, no evidence of corrosion was associated with any of the treatments. Fumigant treatments below the bolt holes continue to eliminate decay fungi, although samples removed from further down the pole indicate an incoIr)1ete distribution of MIT. These tests will be reevaluated this coming year. Detecting Early Decay and Estimating Residual Strength: We continue to evaluate the use of fluorescent coupled lectins and infra-red spectroscopy for detecting fungi in wood and early decay under controlled laboratory conditions. We have also continued evaluation of longitudinal compression (L) as a measure of ultite wood strength using a series of 27 Ldgepole pine posts. While the dense knot clusters interferred with the analysis, LCS, in combination with other parameters, was a reasonably good predictor of bending strength. These tests will continue with more uniform material. iv In addition to tests of LCS, we have evaluated the ability of small scal e tests to determine the strength of various wood pole connectors. Out results were in close agreement with those obtained using full scale tests aii illustrate the value of using small r1 e tests to develop strength information. Initiation of Decay in Air-Seasoning Douglas-fir: We continue to evaluate the data developed in the air-seasoning st1wies. This past year we began to develop information on the effects of various colony sizes on wood strength. This data will help us assign strength values to the colony size data we ha developed frau the air-seasoning study. At present, only Peniophora spp. has been tested, but . carbonica, P. placenta, and Haematostereum sanguinolentuin will also be included. Evaluation of the teinperatures required to eliminate fungi from Douglas-f ir poles also continue. We have ccatpleted 9 test charges which indicate that the penta treatmants involving a Boulton-seasoning cycle result in a ixre than adequate heating of the wood, while steam treants associated with amnniacal copper arsenate are nre variable. We feel that longer heating periods are required for poles greater than 12 inches in diamater, but that the current 6 hour steam period will result in heating of the center to 67 C for over 1 hour in smaller poles. Microfungi in Douglas-fir Poles: We continue to evaluate the effects of nticrofungi on properties of fumigant treated Douglas-fir poles. These tests indicate that prior colonization of fumigant treated wood by Scytalidium or Trichoderma species resulted in lower weight losses by P. placenta and . carbonica. Evaluation of a Cellon treated Douglas-fir laminated beam indicated that V severe penta depletion was associated with virtually all of the surface decay present. This beam had only been in service for 12 years in an extremely dry climate arxl it is unclear why the decay was so rapid. Close

• 76. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1990

  Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1990 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication of Vapam 18 years after the initial application eliminated fungi which had recolonized the poles. Methylisothiocyanate (MITC) continues to protect Douglas-fir poles 12 years after application. Gelatin encapsulation of MITC or chioropicrin appears to have no negative influence on fungitoxicity of these chemicals. Application of water to decompose the gelatin accelerated initial chemical release, but had no longterm effects on performance. A series of laboratory trials have been established to evaluate the performance of sodium n-methyldithiocarbamate (NaMDC), the active ingredient of Vapam. This chemical decomposes more slowly than the liquid formulations and a number of additives are being evaluated to accelerated decomposition. Along with the solid NaMDC, a pelletized formulation of Vapam was evaluated which contained 15 or 40 % NaMDC. These evaluations indicated that the addition of water accelerates release, but the fungal survival in these tests was more variable. The results suggest that a dosage 2 times greater than the liquid formulation is required for effective fungal control; however, further tests are planned to confirm these results. The evaluations of MITC-FUME in Douglas-fir and southern pine poles indicated that MITC has moved to a greater extent in Douglas-fir. Both closed tube bioassays and gas chromatographic analyses of ethyl acetate extracts of wood samples indicated that MITC was present at higher levels in Douglas-fir poles. Southern pine is far more permeable than Douglas-fir and MITC movement should be more rapid in this species. Further tests are planned to identify the nature of this delayed movement. 11 Evaluations of Dazomet, a crystalline solid which decomposes tO produce MITC in wood, indicate that detectable levels of this chemical are present in virtually all of the treatment groups. The decomposition rate of this chemical is normally too slow for effective fungal control and these trials are examining the ability of various additives to accelerate decomposition. Further evaluations of pole sections treated with Dazomet and selected additives are underway. A study to evaluate the effect of voids on fumigant effectivness suggests that voids do not adversely affect MITC movement through Douglas-fir pole sections. These results indicate that treatment of voids should be costeffective if the chemical is not applied directly to the void and if the pole retains a sufficient degree of strength. We continue to develop and refine a model for simulating the movement of MITC through Douglas-fir under varying temperature and moisture conditions. The model has been improved to permit three dimensional evaluations, but the times required for computation are still somewhat long. Further evaluations using a variety of environmental conditions are planned. Evaluations of potential replacements for pentachiorophenol for treatment of western redcedar sapwood and field drilled bolt holes have identified several promising alternatives. These chemicals are now under study in several modified field and laboratory tests. Field trials of several potential treatments for field drilled bolt holes indicate that Boracol 40, disodium octaborate tetrahydrate and ammonium bifluoride provided excellent protection over an 8 year period. These formulations all are relatively safe and can be easily applied in the field. 111 A laboratory trial to evaluate the effects of selected basidiomycetes on strength of Douglas-fir sapwood and heartwood has concluded. Fungal density, measured as the average number of fungi colonies per beam, gradually increased in all of the beams while longitudinal compression strength (LCS), modulus of rupture (MOR), and modulus of elesticity (MOE) slowly declined. Of the measurements, LCS appeared to be most useful, probably owing to the increased number of sampling sites per beam. The results indicate that the degree of colonization was not a good indicator of wood strength effects. The value of kerfing for decreasing post-treatment checking and improving the service life of Douglas-fir poles was evaluated using a series of inspection reports from a local utility. Kerfed transmission poles had substantially lower rates of internal decay and rejection, but there appeared to be little difference in the rate of decay between kerfed and non-kerfed distribution poles. The evaluation of disodium octaborate tetrahydrate for preventing colonization of air-seasoning Douglas-fir pole sections has been completed. Spraying with a 10 % boric acid equivalent solution (BAE) at 6 month intervals provided the greatest degree of protection, although dipping in a 20 % BAE solution at the start of air-seasoning produced a similar degree of protection. As expected, fungal colonization was far lower at the dryer Oroville site and borate treatment had little influence on the degree of fungal colonization at this site. The results indicate that borate treatment at the start of airseasoning is a viable method for limiting fungal colonization in moist airseasoning sites west of the Cascade Mountains. Evaluations of the tolerance of Stereum sanguinolentum and Peniophora spp. to elevated temperature exposures indicated that both of these fungi were extremely sensitive to elevated temperatures. The lack of long-term survival structures in these fungi probably accounts for this susceptibility to heat. iv A series of trials which measured internal temperatures in Douglas-fir pole sections during treatment with ammoniacal copper arsenate were used to develop a model for predicting internal heating during steaming. The results indicated that previous heating curves were overly optimistic in their prediction of heating. A series of heating curves for various pole diameters and starting conditions are presented. A number of externally applied groundline treatments are under evaluation in a field trial at Peavy Arboretum and a second trial will be established in the San Francisco Bay area. Seven formulations (including standards) are included. The Peavy site will be sampled in the next few months. The performance of copper naphthenate in western wood species is being evaluated in a series of small western redcedar sapwood stakelets which have been treated to a range of retentions and exposed in the fungus cellar. The results will be used to help confirm the performance of copper naphthenate in this species. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1990 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluations of previously established field trials indicate that chioropicrin, and Vorlex continue to provide protection to Douglas-fir poles, although the degree of protection is diminishing. Reapplication of Vapam 18 years after the initial application eliminated fungi which had recolonized the poles. Methylisothiocyanate (MITC) continues to protect Douglas-fir poles 12 years after application. Gelatin encapsulation of MITC or chioropicrin appears to have no negative influence on fungitoxicity of these chemicals. Application of water to decompose the gelatin accelerated initial chemical release, but had no longterm effects on performance. A series of laboratory trials have been established to evaluate the performance of sodium n-methyldithiocarbamate (NaMDC), the active ingredient of Vapam. This chemical decomposes more slowly than the liquid formulations and a number of additives are being evaluated to accelerated decomposition. Along with the solid NaMDC, a pelletized formulation of Vapam was evaluated which contained 15 or 40 % NaMDC. These evaluations indicated that the addition of water accelerates release, but the fungal survival in these tests was more variable. The results suggest that a dosage 2 times greater than the liquid formulation is required for effective fungal control; however, further tests are planned to confirm these results. The evaluations of MITC-FUME in Douglas-fir and southern pine poles indicated that MITC has moved to a greater extent in Douglas-fir. Both closed tube bioassays and gas chromatographic analyses of ethyl acetate extracts of wood samples indicated that MITC was present at higher levels in Douglas-fir poles. Southern pine is far more permeable than Douglas-fir and MITC movement should be more rapid in this species. Further tests are planned to identify the nature of this delayed movement. 11 Evaluations of Dazomet, a crystalline solid which decomposes tO produce MITC in wood, indicate that detectable levels of this chemical are present in virtually all of the treatment groups. The decomposition rate of this chemical is normally too slow for effective fungal control and these trials are examining the ability of various additives to accelerate decomposition. Further evaluations of pole sections treated with Dazomet and selected additives are underway. A study to evaluate the effect of voids on fumigant effectivness suggests that voids do not adversely affect MITC movement through Douglas-fir pole sections. These results indicate that treatment of voids should be costeffective if the chemical is not applied directly to the void and if the pole retains a sufficient degree of strength. We continue to develop and refine a model for simulating the movement of MITC through Douglas-fir under varying temperature and moisture conditions. The model has been improved to permit three dimensional evaluations, but the times required for computation are still somewhat long. Further evaluations using a variety of environmental conditions are planned. Evaluations of potential replacements for pentachiorophenol for treatment of western redcedar sapwood and field drilled bolt holes have identified several promising alternatives. These chemicals are now under study in several modified field and laboratory tests. Field trials of several potential treatments for field drilled bolt holes indicate that Boracol 40, disodium octaborate tetrahydrate and ammonium bifluoride provided excellent protection over an 8 year period. These formulations all are relatively safe and can be easily applied in the field. 111 A laboratory trial to evaluate the effects of selected basidiomycetes on strength of Douglas-fir sapwood and heartwood has concluded. Fungal density, measured as the average number of fungi colonies per beam, gradually increased in all of the beams while longitudinal compression strength (LCS), modulus of rupture (MOR), and modulus of elesticity (MOE) slowly declined. Of the measurements, LCS appeared to be most useful, probably owing to the increased number of sampling sites per beam. The results indicate that the degree of colonization was not a good indicator of wood strength effects. The value of kerfing for decreasing post-treatment checking and improving the service life of Douglas-fir poles was evaluated using a series of inspection reports from a local utility. Kerfed transmission poles had substantially lower rates of internal decay and rejection, but there appeared to be little difference in the rate of decay between kerfed and non-kerfed distribution poles. The evaluation of disodium octaborate tetrahydrate for preventing colonization of air-seasoning Douglas-fir pole sections has been completed. Spraying with a 10 % boric acid equivalent solution (BAE) at 6 month intervals provided the greatest degree of protection, although dipping in a 20 % BAE solution at the start of air-seasoning produced a similar degree of protection. As expected, fungal colonization was far lower at the dryer Oroville site and borate treatment had little influence on the degree of fungal colonization at this site. The results indicate that borate treatment at the start of airseasoning is a viable method for limiting fungal colonization in moist airseasoning sites west of the Cascade Mountains. Evaluations of the tolerance of Stereum sanguinolentum and Peniophora spp. to elevated temperature exposures indicated that both of these fungi were extremely sensitive to elevated temperatures. The lack of long-term survival structures in these fungi probably accounts for this susceptibility to heat. iv A series of trials which measured internal temperatures in Douglas-fir pole sections during treatment with ammoniacal copper arsenate were used to develop a model for predicting internal heating during steaming. The results indicated that previous heating curves were overly optimistic in their prediction of heating. A series of heating curves for various pole diameters and starting conditions are presented. A number of externally applied groundline treatments are under evaluation in a field trial at Peavy Arboretum and a second trial will be established in the San Francisco Bay area. Seven formulations (including standards) are included. The Peavy site will be sampled in the next few months. The performance of copper naphthenate in western wood species is being evaluated in a series of small western redcedar sapwood stakelets which have been treated to a range of retentions and exposed in the fungus cellar. The results will be used to help confirm the performance of copper naphthenate in this species. Close