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• 61. [Article] An integrated approach using Bacillus subtilis B26 and essential oils to limit fungal discoloration of wood

  This is the publisher’s final pdf. The article is copyrighted by the authors and published by the Department of Wood and Paper Science, College of Natural Resources, North Carolina State University. The ...

  Citation × Citation Citation Abstract Copy Title: An integrated approach using Bacillus subtilis B26 and essential oils to limit fungal discoloration of wood Author: Freitag, Camille M., Morrell, Jeffrey J., Chang, Jianmin, Wang, Yu, Karchesy, Joseph J. This is the publisher’s final pdf. The article is copyrighted by the authors and published by the Department of Wood and Paper Science, College of Natural Resources, North Carolina State University. The published article can be found at: http://www.bioresourcesjournal.com/. Title: An integrated approach using Bacillus subtilis B26 and essential oils to limit fungal discoloration of wood Author: Freitag, Camille M., Morrell, Jeffrey J., Chang, Jianmin, Wang, Yu, Karchesy, Joseph J. This is the publisher’s final pdf. The article is copyrighted by the authors and published by the Department of Wood and Paper Science, College of Natural Resources, North Carolina State University. The published article can be found at: http://www.bioresourcesjournal.com/. Close

• 62. [Article] Effects of incising on lumber strength and stiffness: Relationships between incision density and depth, species, and MSR grade

  This report describes the relationship of incising-induced strength loss in bending as a function of preservative treatment and incising pattern, density, and depth of penetration for various machine stress-rated ...

  Citation × Citation Citation Abstract Copy Title: Effects of incising on lumber strength and stiffness: Relationships between incision density and depth, species, and MSR grade Author: Morrell, Jeffrey J., Winandy, Jerrold E. This report describes the relationship of incising-induced strength loss in bending as a function of preservative treatment and incising pattern, density, and depth of penetration for various machine stress-rated (MSR) grades of full-size 2 by 4 Douglas-fir, Hem-Fir, and Spruce-Pine-Fir (South) dimension lumber. This study may represent a worst-case "incising effects" scenario: although the incising patterns and depths selected for study represent commonly used industrial practices, the incising process itself was performed on dry lumber, which is not the standard practice of the treating industry. As we had expected on the basis of Canadian results, incising affected bending properties, such as modulus of elasticity, modulus of rupture, and work to maximum load. Our results show that the combined incising-preservative effect on mean property values for lumber incised in the dry condition prior to treatment was in the range of a 0 to 10% loss in modulus of elasticity, 15% to 25% loss in modulus of rupture, and 30% to 50% loss in work to maximum load. The effect on properties at the lower end of the distribution, such as the allowable stress design value F, was equal to or less than that on mean properties for the three species groups evaluated. While these results specifically apply to only MSR-graded standard 38-mm- (nominal 2-inch-) thick lumber and to lumber incised in the dry condition prior to treatment, they do imply that the new U.S. design adjustments for C, in modulus of elasticity of 0.95 and F, of 0.85 may not be sufficient for incised and treated material used in dry in-service conditions. Title: Effects of incising on lumber strength and stiffness: Relationships between incision density and depth, species, and MSR grade Author: Morrell, Jeffrey J., Winandy, Jerrold E. This report describes the relationship of incising-induced strength loss in bending as a function of preservative treatment and incising pattern, density, and depth of penetration for various machine stress-rated (MSR) grades of full-size 2 by 4 Douglas-fir, Hem-Fir, and Spruce-Pine-Fir (South) dimension lumber. This study may represent a worst-case "incising effects" scenario: although the incising patterns and depths selected for study represent commonly used industrial practices, the incising process itself was performed on dry lumber, which is not the standard practice of the treating industry. As we had expected on the basis of Canadian results, incising affected bending properties, such as modulus of elasticity, modulus of rupture, and work to maximum load. Our results show that the combined incising-preservative effect on mean property values for lumber incised in the dry condition prior to treatment was in the range of a 0 to 10% loss in modulus of elasticity, 15% to 25% loss in modulus of rupture, and 30% to 50% loss in work to maximum load. The effect on properties at the lower end of the distribution, such as the allowable stress design value F, was equal to or less than that on mean properties for the three species groups evaluated. While these results specifically apply to only MSR-graded standard 38-mm- (nominal 2-inch-) thick lumber and to lumber incised in the dry condition prior to treatment, they do imply that the new U.S. design adjustments for C, in modulus of elasticity of 0.95 and F, of 0.85 may not be sufficient for incised and treated material used in dry in-service conditions. Close

• 63. [Article] Effect of treatment postfixation practices on copper migration from alkaline-copper-treated Douglas-fir lumber

  The potential for preservative migration from treated wood exposed in or above aquatic environments has become a major concern in some parts of the United States. Best management practices (BMP) were designed ...

  Citation × Citation Citation Abstract Copy Title: Effect of treatment postfixation practices on copper migration from alkaline-copper-treated Douglas-fir lumber Author: Morrell, Jeffrey J., Ye, Min The potential for preservative migration from treated wood exposed in or above aquatic environments has become a major concern in some parts of the United States. Best management practices (BMP) were designed to decrease the potential environmental footprint of treated wood, but there are few studies assessing the efficacy of these processes. The effects of applying various post-treatment BMP heating processes on loss of copper from copper azole Type B (CA) and alkaline copper quaternary compound Type B (ACQ)-treated Douglas fir were evaluated using a simulated overhead rainfall apparatus. This study examined the initial phases of wetting, which previous studies have shown to pose the highest risk to aquatic life. Immersion of CA-treated wood in hot water or a dilute ammonia solution was associated with lower levels of copper in rainfall runoff than steaming or kiln-drying, whereas steaming was associated higher copper levels. Similar trials with ACQ revealed that various heating treatments produced results that were similar to those found with air-drying. The results suggest that there might be opportunities for decreasing copper losses from CA-treated wood through further refinements in post-treatment BMPs. They also indicate that post-treatment heating processes that do not dry the wood still produce products that experience copper losses similar to those found with air-dried material. Title: Effect of treatment postfixation practices on copper migration from alkaline-copper-treated Douglas-fir lumber Author: Morrell, Jeffrey J., Ye, Min The potential for preservative migration from treated wood exposed in or above aquatic environments has become a major concern in some parts of the United States. Best management practices (BMP) were designed to decrease the potential environmental footprint of treated wood, but there are few studies assessing the efficacy of these processes. The effects of applying various post-treatment BMP heating processes on loss of copper from copper azole Type B (CA) and alkaline copper quaternary compound Type B (ACQ)-treated Douglas fir were evaluated using a simulated overhead rainfall apparatus. This study examined the initial phases of wetting, which previous studies have shown to pose the highest risk to aquatic life. Immersion of CA-treated wood in hot water or a dilute ammonia solution was associated with lower levels of copper in rainfall runoff than steaming or kiln-drying, whereas steaming was associated higher copper levels. Similar trials with ACQ revealed that various heating treatments produced results that were similar to those found with air-drying. The results suggest that there might be opportunities for decreasing copper losses from CA-treated wood through further refinements in post-treatment BMPs. They also indicate that post-treatment heating processes that do not dry the wood still produce products that experience copper losses similar to those found with air-dried material. Close

• 64. [Article] Potential for using through-boring to improve groundline treatment of Australian wood species: A preliminary study

  An aging electricity distribution system and reduced availability of naturally durable tropical hardwoods in Australia will combine in the next decade to produce a major shortage of poles. One approach ...

  Citation × Citation Citation Abstract Copy Title: Potential for using through-boring to improve groundline treatment of Australian wood species: A preliminary study Author: Morrell, Jeffrey J., Norton, Jack An aging electricity distribution system and reduced availability of naturally durable tropical hardwoods in Australia will combine in the next decade to produce a major shortage of poles. One approach to mitigating this shortage is to utilize lower durability species and improve the penetration of preservatives into the refractory heartwood by introducing additional pretreatment processes. A potential method for improving preservative penetration in the critical ground-line zone is throughboring. This process, in which holes are drilled through the pole perpendicular to the grain in the ground-line zone, is widely used in the western United States for treatment of Douglas-fir and may be suitable for many Australian wood species. The potential for improving heartwood penetration in eucalypts with alkaline-copper-quaternary (ACQ) compound was assessed on heartwood specimens from four species (Eucalyptus cloeziana F.Muell., E. grandis W.Hill ex Maiden, E. obliqua L’Her. and E. pellita F.Muell.) and Lophostemon confertus (R.Br.) Peter G.Wilson & J.T.Waterh). Longitudinal ACQ penetration was extremely shallow in L. confertus and only slightly better in E. cloeziana. Longitudinal penetration was good in both E. obliqua and E. pellita, although there was some variation in treatment results with length of pressure period. The results suggest that through-boring might be a reasonable approach for achieving heartwood penetration in some Eucalyptus species, although further studies are required to assess additional treatment schedules and to determine the effects of the process on flexural properties of the poles. Title: Potential for using through-boring to improve groundline treatment of Australian wood species: A preliminary study Author: Morrell, Jeffrey J., Norton, Jack An aging electricity distribution system and reduced availability of naturally durable tropical hardwoods in Australia will combine in the next decade to produce a major shortage of poles. One approach to mitigating this shortage is to utilize lower durability species and improve the penetration of preservatives into the refractory heartwood by introducing additional pretreatment processes. A potential method for improving preservative penetration in the critical ground-line zone is throughboring. This process, in which holes are drilled through the pole perpendicular to the grain in the ground-line zone, is widely used in the western United States for treatment of Douglas-fir and may be suitable for many Australian wood species. The potential for improving heartwood penetration in eucalypts with alkaline-copper-quaternary (ACQ) compound was assessed on heartwood specimens from four species (Eucalyptus cloeziana F.Muell., E. grandis W.Hill ex Maiden, E. obliqua L’Her. and E. pellita F.Muell.) and Lophostemon confertus (R.Br.) Peter G.Wilson & J.T.Waterh). Longitudinal ACQ penetration was extremely shallow in L. confertus and only slightly better in E. cloeziana. Longitudinal penetration was good in both E. obliqua and E. pellita, although there was some variation in treatment results with length of pressure period. The results suggest that through-boring might be a reasonable approach for achieving heartwood penetration in some Eucalyptus species, although further studies are required to assess additional treatment schedules and to determine the effects of the process on flexural properties of the poles. Close

• 65. [Article] Diffusion and sorption of the fumigant methylisothiocyanate in Douglas-fir wood

  The influence of moisture content (MC) and conventional preservative treatment on methylisothiocyanate (MIT) sorption and diffusion were investigated in Douglas-fir wood. In wood at 0% MC, the ratio of ...

  Citation × Citation Citation Abstract Copy Title: Diffusion and sorption of the fumigant methylisothiocyanate in Douglas-fir wood Author: Morrell, Jeffrey J., Zahora, Andrew R. The influence of moisture content (MC) and conventional preservative treatment on methylisothiocyanate (MIT) sorption and diffusion were investigated in Douglas-fir wood. In wood at 0% MC, the ratio of equilibrium MIT adsorption to desorption concentrations was low (0.2), but it increased rapidly to about 0.94 above 18% MC. Partition coefficients (bound/vapor MIT) for MIT adsorption to wood increased with wood moisture from 0% to about 12%. At higher moisture contents, sorbed water apparently interfered with MIT sorption, and partition coefficients decreased with wood moisture content for both MIT adsorption and desorption. Steady-state diffusion coefficients were dependent on wood moisture content, but were at least 200 times higher for longitudinal movement of MIT in Douglas-fir heartwood than for transverse movement. Diffusion coefficients increased with wood moisture content below the fiber-saturation point, apparently as a result of improved bound MIT diffusion. Increasing wood moisture content from 22% to 80% reduced longitudinal MIT diffusion almost threefold, but did not greatly influence tangential MIT diffusion. Radial movement of MIT was about seven times faster in Douglas-fir sapwood than in heartwood. Preservative treatment with waterborne chromated copper arsenate did not influence MIT sorption or diffusion in sapwood at 15% MC, but impregnation with P-9 Type A oil restricted MIT movement and may provide a barrier to fumigant loss. Title: Diffusion and sorption of the fumigant methylisothiocyanate in Douglas-fir wood Author: Morrell, Jeffrey J., Zahora, Andrew R. The influence of moisture content (MC) and conventional preservative treatment on methylisothiocyanate (MIT) sorption and diffusion were investigated in Douglas-fir wood. In wood at 0% MC, the ratio of equilibrium MIT adsorption to desorption concentrations was low (0.2), but it increased rapidly to about 0.94 above 18% MC. Partition coefficients (bound/vapor MIT) for MIT adsorption to wood increased with wood moisture from 0% to about 12%. At higher moisture contents, sorbed water apparently interfered with MIT sorption, and partition coefficients decreased with wood moisture content for both MIT adsorption and desorption. Steady-state diffusion coefficients were dependent on wood moisture content, but were at least 200 times higher for longitudinal movement of MIT in Douglas-fir heartwood than for transverse movement. Diffusion coefficients increased with wood moisture content below the fiber-saturation point, apparently as a result of improved bound MIT diffusion. Increasing wood moisture content from 22% to 80% reduced longitudinal MIT diffusion almost threefold, but did not greatly influence tangential MIT diffusion. Radial movement of MIT was about seven times faster in Douglas-fir sapwood than in heartwood. Preservative treatment with waterborne chromated copper arsenate did not influence MIT sorption or diffusion in sapwood at 15% MC, but impregnation with P-9 Type A oil restricted MIT movement and may provide a barrier to fumigant loss. Close

• 66. [Article] Effect of wetting on performance of small-scale shear walls

  Wood shear walls are the main lateral force-resisting system for wood-frame construction. Water intrusion and subsequent decay around connections can significantly impact shear wall behavior, but these ...

  Citation × Citation Citation Abstract Copy Title: Effect of wetting on performance of small-scale shear walls Author: Morrell, Jeffrey J., Sinha, Arijit, King, David T. Wood shear walls are the main lateral force-resisting system for wood-frame construction. Water intrusion and subsequent decay around connections can significantly impact shear wall behavior, but these problems are seldom studied. In this study, effects of water intrusion and fungal attack on shear wall capacity were examined using small-scale (610- x 610-mm) shear walls that were monitored with time using destructive monotonic tests. Results were compared with tests of dry and water control samples. Although fungal colonization was not successful under the conditions tested, wetting (with or without fungal inoculation) produced interesting effects on shear wall capacity. Wetting alone initially increased shear wall capacity, possibly because of fastener corrosion. Observations and digital image correlation data suggest that tensile forces in the uplift corner of the shear walls governed failure modes, which were primarily nail withdrawal, nail pull-through, flake debonding, and cross-grain tension. Wetting affected rigidity of oriented strandboard and led to more frequent nail pull-through. Although failure loads did not differ between the groups, failure modes and displacement at maximum load suggested decreased performance of wetted shear walls. The results suggest that slight amounts (8% overall) of wetting do not negatively affect shear wall performance. However, the effects of prolonged wetting on capacity merit further study. Title: Effect of wetting on performance of small-scale shear walls Author: Morrell, Jeffrey J., Sinha, Arijit, King, David T. Wood shear walls are the main lateral force-resisting system for wood-frame construction. Water intrusion and subsequent decay around connections can significantly impact shear wall behavior, but these problems are seldom studied. In this study, effects of water intrusion and fungal attack on shear wall capacity were examined using small-scale (610- x 610-mm) shear walls that were monitored with time using destructive monotonic tests. Results were compared with tests of dry and water control samples. Although fungal colonization was not successful under the conditions tested, wetting (with or without fungal inoculation) produced interesting effects on shear wall capacity. Wetting alone initially increased shear wall capacity, possibly because of fastener corrosion. Observations and digital image correlation data suggest that tensile forces in the uplift corner of the shear walls governed failure modes, which were primarily nail withdrawal, nail pull-through, flake debonding, and cross-grain tension. Wetting affected rigidity of oriented strandboard and led to more frequent nail pull-through. Although failure loads did not differ between the groups, failure modes and displacement at maximum load suggested decreased performance of wetted shear walls. The results suggest that slight amounts (8% overall) of wetting do not negatively affect shear wall performance. However, the effects of prolonged wetting on capacity merit further study. Close

• 67. [Article] The effects of chromated copper arsenate and ammoniacal copper zinc arsenate on shear strength development of phenolic resin to Sitka spruce bonds

  Preservative treatment of whole, wood-based composite products (mainly panels) has disadvantages; problems largely stem from swelling, strength loss, and incomplete or inappropriate penetration during ...

  Citation × Citation Citation Abstract Copy Title: The effects of chromated copper arsenate and ammoniacal copper zinc arsenate on shear strength development of phenolic resin to Sitka spruce bonds Author: Prasad, T.R. Narayana, Humphrey, Philip E., Morrell, Jeffrey J. Preservative treatment of whole, wood-based composite products (mainly panels) has disadvantages; problems largely stem from swelling, strength loss, and incomplete or inappropriate penetration during treatment, and distortion during redrying. Pretreatment of comminuted wood prior to mat lay-up is one alternative, though the addition of chemicals may affect bonding during subsequent pressing. With this possibility in mind, the strength accumulation of small test bonds (1 5 x 4 mm) between variously treated thin wood pieces was investigated. Pieces of Sitka spruce (sliced 0.8 x 15 x 150 mm) were treated with one of four concentrations (0.25 to 1.50% oxide basis) of either chromated copper arsenate or ammoniacal copper zinc arsenate. An automated device was used to form and test lap-shear specimens from matched pairs of variously treated wood and a phenol-formaldehyde adhesive. Each specimen was pulled immediately after pressing to measure the accumulated shear strength of the bond. Pressing times ranged from 10 to 300 sec at 95 C and 1.5 MPa, and this enabled near-isothermal strength-development plots to be constructed for each level of pretreatment. The plots suggested that preservative pretreatment did not significantly affect shear strength development rates at the chemical retention levels and pressing and testing conditions employed. Title: The effects of chromated copper arsenate and ammoniacal copper zinc arsenate on shear strength development of phenolic resin to Sitka spruce bonds Author: Prasad, T.R. Narayana, Humphrey, Philip E., Morrell, Jeffrey J. Preservative treatment of whole, wood-based composite products (mainly panels) has disadvantages; problems largely stem from swelling, strength loss, and incomplete or inappropriate penetration during treatment, and distortion during redrying. Pretreatment of comminuted wood prior to mat lay-up is one alternative, though the addition of chemicals may affect bonding during subsequent pressing. With this possibility in mind, the strength accumulation of small test bonds (1 5 x 4 mm) between variously treated thin wood pieces was investigated. Pieces of Sitka spruce (sliced 0.8 x 15 x 150 mm) were treated with one of four concentrations (0.25 to 1.50% oxide basis) of either chromated copper arsenate or ammoniacal copper zinc arsenate. An automated device was used to form and test lap-shear specimens from matched pairs of variously treated wood and a phenol-formaldehyde adhesive. Each specimen was pulled immediately after pressing to measure the accumulated shear strength of the bond. Pressing times ranged from 10 to 300 sec at 95 C and 1.5 MPa, and this enabled near-isothermal strength-development plots to be constructed for each level of pretreatment. The plots suggested that preservative pretreatment did not significantly affect shear strength development rates at the chemical retention levels and pressing and testing conditions employed. Close

• 68. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; September 1995

  Previously established field trials of MTTC-Fume continue to show that this chemical remains in Douglas-fir and southern pine poles at fungitoxic levels 5 years after treatment. In general, increasing ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; September 1995 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Previously established field trials of MTTC-Fume continue to show that this chemical remains in Douglas-fir and southern pine poles at fungitoxic levels 5 years after treatment. In general, increasing dosages resulted in higher chemical levels in the poles. All of the MITC-Fume treatments resulted in higher residual M1TC levels than comparable metham sodium treatments. Field trials with solid basaniid with and without copper sulfate continue to show the promise of this chemical. Basamid treated poles continue to contain MITC at levels which exceed those for comparable metham sodium treatments. These results, which are currently being confirmed in poles in service, indicate that this formulation can deliver fiingitoxic MITC levels to wood in service, without the risk of spills associated with metham sodium. We have completed trials with gelled and pelletized metham sodium formulations. Both of these formulations offered improved safety during application. Initial laboratory trials also suggested that the gelled formulation was more effective than comparable liquid metham sodium. Field trials, however, indicate that the formulations provided protection comparable to the liquid formulation in poles over the test period. The gelled formulation still offers the advantage of reduced risks of spills during application. Trials are also continuing with various solid, water diffusible treatments for arresting internal decay. Trials of fused borate rods continue to show that these treatments require more moisture for effective movement in Douglas-fir poles. Field trials have also been established with borate rods with glycol as an additive to determine if glycols can accelerate diffusion in drier wood. The poles in these trials have also been sensored to monitor internal moisture changes over time in order to better correlate boron diffusion with wood moisture content. Trials underway with a boronlfluoride rod indicate that the boron is diffusing well from these rods, while the fluoride is moving somewhat slower. Neither chemical has approached a fiungal threshold one year after treatment, but the combination of chemicals may lead to more effective fungal control. Trials with pelletized metham sodium/basamid mixtures suggests that using ratios of these two chemicals can produce an initial rapid burst ofMITC release followed by a slower MITC release with time. This combination allows for rapid control of existing fungal infestations followed by long term protection against reinvasion. These laboratory trials will be further confirmed with field trials. The trials to evaluate the effects of voids on fumigant movement initially suggested that voids have little influence on subsequent fumigant levels on either side of the void. Sampling 8 years after treatment, however, indicates that chioropicrin levels were generally higher in poles without voids. We plan further trials of actual field poles containing voids to confirm these effects. Trials to identify treatments for protecting the sapwood of western redcedar poles as well as wood exposed in field drilled bolt holes are continuing. Trials in western redcedar sapwood have identified a number of chemicals which can be remedially applied to protect this wood against fungal attack. At present, however, commercial pole spraying has largely ceased making further field trials difficult. Field trials to identify treatments for protecting untreated wood exposed during drilling for various pole attachments continue to show that diffusible boron and fluoride compounds provide excellent long term protection against flingal attack. The protective effects of one diffusible treatment, Boracol, however, has begun to decline. Further sampling will be undertaken to identify the long term effectiveness of the remaining treatments. Trials to identify enhanced patterns for through boring of Douglas-fir poles are complete. The results indicate that patterns as widely spaced as 400 mm apart longitudinally still produce a nearly completely treated pole i n the through bored zone. Pentachlorophenol levels in the through bored zone were generally above the threshold for ftrngal growth. Prior sampling of Douglas-fir poles in service suggest that even poles with small skips in the through bored zone contained no evidence of internal decay. These results suggest that the through boring pattern can be extended without adversely risking pole service life. A reduced through boring pattern would decrease treatment costs while minimizing impacts on pole strength. Trials to evaluate the application of boron to freshly peeled Douglas-fir poles as a means of preventing fungal colonization using a thermal process suggest that thermal treatment failed to produce a boron loading sufilcient to permit subsequent diffusion across the pole section after a 3 month diffusion period. Evaluations of various external groundline preservative formulations continue to indicate that replacement formulations based upon copper naphthenate, boron or fluoride perform comparably to earlier formulations employing pentachlorophenol and creosote. Pentachlorophenol levels in some treatments have fallen below the threshold for fungal growth, while those in all of the replacement treatments remain above a U protective level. These results suggest that the newer groundline preservative systems should provide a reasonable level of protection against external decay. Laboratory trials to better understand the levels of combinations of chemicals required for protection in the groundline zone are continuing. Fungal cellar evaluations of copper naphthenate treated western redcedar continue to show excellent performance at levels specified in the American Wood Preservers' Association Standards. Performance is generally better for wood which was freshly sawn prior to treatment, while wood cuts from weathered poles in service has provided slightly lower levels of protection. The weather wood apparently has higher permeability, making it more likely to lose chemical in soil contact. Further evaluations are planned. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; September 1995 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Previously established field trials of MTTC-Fume continue to show that this chemical remains in Douglas-fir and southern pine poles at fungitoxic levels 5 years after treatment. In general, increasing dosages resulted in higher chemical levels in the poles. All of the MITC-Fume treatments resulted in higher residual M1TC levels than comparable metham sodium treatments. Field trials with solid basaniid with and without copper sulfate continue to show the promise of this chemical. Basamid treated poles continue to contain MITC at levels which exceed those for comparable metham sodium treatments. These results, which are currently being confirmed in poles in service, indicate that this formulation can deliver fiingitoxic MITC levels to wood in service, without the risk of spills associated with metham sodium. We have completed trials with gelled and pelletized metham sodium formulations. Both of these formulations offered improved safety during application. Initial laboratory trials also suggested that the gelled formulation was more effective than comparable liquid metham sodium. Field trials, however, indicate that the formulations provided protection comparable to the liquid formulation in poles over the test period. The gelled formulation still offers the advantage of reduced risks of spills during application. Trials are also continuing with various solid, water diffusible treatments for arresting internal decay. Trials of fused borate rods continue to show that these treatments require more moisture for effective movement in Douglas-fir poles. Field trials have also been established with borate rods with glycol as an additive to determine if glycols can accelerate diffusion in drier wood. The poles in these trials have also been sensored to monitor internal moisture changes over time in order to better correlate boron diffusion with wood moisture content. Trials underway with a boronlfluoride rod indicate that the boron is diffusing well from these rods, while the fluoride is moving somewhat slower. Neither chemical has approached a fiungal threshold one year after treatment, but the combination of chemicals may lead to more effective fungal control. Trials with pelletized metham sodium/basamid mixtures suggests that using ratios of these two chemicals can produce an initial rapid burst ofMITC release followed by a slower MITC release with time. This combination allows for rapid control of existing fungal infestations followed by long term protection against reinvasion. These laboratory trials will be further confirmed with field trials. The trials to evaluate the effects of voids on fumigant movement initially suggested that voids have little influence on subsequent fumigant levels on either side of the void. Sampling 8 years after treatment, however, indicates that chioropicrin levels were generally higher in poles without voids. We plan further trials of actual field poles containing voids to confirm these effects. Trials to identify treatments for protecting the sapwood of western redcedar poles as well as wood exposed in field drilled bolt holes are continuing. Trials in western redcedar sapwood have identified a number of chemicals which can be remedially applied to protect this wood against fungal attack. At present, however, commercial pole spraying has largely ceased making further field trials difficult. Field trials to identify treatments for protecting untreated wood exposed during drilling for various pole attachments continue to show that diffusible boron and fluoride compounds provide excellent long term protection against flingal attack. The protective effects of one diffusible treatment, Boracol, however, has begun to decline. Further sampling will be undertaken to identify the long term effectiveness of the remaining treatments. Trials to identify enhanced patterns for through boring of Douglas-fir poles are complete. The results indicate that patterns as widely spaced as 400 mm apart longitudinally still produce a nearly completely treated pole i n the through bored zone. Pentachlorophenol levels in the through bored zone were generally above the threshold for ftrngal growth. Prior sampling of Douglas-fir poles in service suggest that even poles with small skips in the through bored zone contained no evidence of internal decay. These results suggest that the through boring pattern can be extended without adversely risking pole service life. A reduced through boring pattern would decrease treatment costs while minimizing impacts on pole strength. Trials to evaluate the application of boron to freshly peeled Douglas-fir poles as a means of preventing fungal colonization using a thermal process suggest that thermal treatment failed to produce a boron loading sufilcient to permit subsequent diffusion across the pole section after a 3 month diffusion period. Evaluations of various external groundline preservative formulations continue to indicate that replacement formulations based upon copper naphthenate, boron or fluoride perform comparably to earlier formulations employing pentachlorophenol and creosote. Pentachlorophenol levels in some treatments have fallen below the threshold for fungal growth, while those in all of the replacement treatments remain above a U protective level. These results suggest that the newer groundline preservative systems should provide a reasonable level of protection against external decay. Laboratory trials to better understand the levels of combinations of chemicals required for protection in the groundline zone are continuing. Fungal cellar evaluations of copper naphthenate treated western redcedar continue to show excellent performance at levels specified in the American Wood Preservers' Association Standards. Performance is generally better for wood which was freshly sawn prior to treatment, while wood cuts from weathered poles in service has provided slightly lower levels of protection. The weather wood apparently has higher permeability, making it more likely to lose chemical in soil contact. Further evaluations are planned. Close

• 69. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1991

  Evaluations of previously established field trials indicate that chioropicrin and Vorlex continue to provide a diminishing level of protection to Douglas-fir poles. Tests of solid methylisothiocyanate ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1991 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 a diminishing level of protection to Douglas-fir poles. Tests of solid methylisothiocyanate (MITC), now in their thirteenth year, indicate that this chemical continues to prevent recolonization of Douglas-fir poles by decay fungi. MITC appears to provide equivalent or better protection than Vorlex. Gelatin encapsulated MITC and chioropicrin also continue to perform well in field trials. Although the gelatin is water soluble and must decompose to release the chemical, the addition of water to the treatment holes did not appear to significantly enhance long-term MITC performance. Laboratory trials to identify safer fumigants indicate that sodium nmethyldithiocarbamate decomposition occurs even in dry wood, although the rate of decomposition is enhanced by the presence of some moisture. A gelled 40 % NaMDC formulation has also been evaluated for its ability to eliminate decay fungi from Douglas-fir heartwood. This formulation has performed better than liquid metham sodium. Field trials are planned with both the solid and gelled NaMDC. Laboratory trials have also been performed to evaluate the toxicity of fused borate rods to Antrodia carbonica and Postia placenta. These two fungi are important decayers of Douglas-fir utility poles. The results indicate that the boron moved well through both wood species, but complete elimination of the test fungus required 6 to 8 weeks. Antrodia carbonica was generally more tolerant of boron than P. placenta. Field trials of fused borate rods indicate that the boron has moved downward from the point of application, but no evidence of upward movement was noted. Trials to evaluate the efficacy of glass-encapsulated M:[TC in Douglas-fir 1 11 and southern pine poles are now in their second year. The results continue to indicate the MITC levels are higher in Douglas-fir poles. The reasons for this descrepancy are unclear, but may reflect an increased MITC loss from the more permeable southern pine poles. Controlled studies of MITC release rates from the glass vials show that the tubes retain chemical for 1 to 2 years under normal conditions. Faster losses occur under more tropical conditions, while little loss occurs in cold conditions. Evaluations of additives to enhance Basamid decomposition in Douglas-fir pole sections indicate that the presence of copper sulfate and pH 12 buffer markedly improve the rate of decomposition to MuG one year after chemical application. More controlled laboratory studies are underway to better understand this effect. The trials to evaluate the effects of voids on fumigant movement continue to indicate that the void has little effect on chemical concentration. These results indicate that fumigant treatment of poles with voids is feasible provided the wood retains adequate strength. Laboratory trials to develop diffusion coefficients for chloropicri.n movement through Douglas-fir heartwood have been developed. As expected, chioropicrin movement was most rapid longitudinally and at the fiber saturation point. Drier wood retained more chemical, slowing diffusion. The diffusion coefficients will be employed in the fumigant model currently being evaluated on MITC. The model indicates that MITC movement was greatest at moderate moisture levels (22 or 44 %), while higher or lower moisture regimes limited chemical movement. The results obtained using the model will be confirmed through laboratory trials and by comparison with the results of chemical analyses performed on the glass-encapsulated MITC trials. The trials to identify potential replacements for pentachlorophenol for Ii' remedial treatments are continuing. A number of chemicals have been identified for both the protection of field drilled bolt holes and the spray treatment of western redcedar sapwood. Spray treatments of the most promising chemicals will be applied to western redcedar poles in service. The identification of small scale tests for detecting decay or estimating residual strength are continuing. We also continue to evaluate the effectiveness of various pretreatments for improving treatment and performance of poles. The effects of through boring and radial drilling patterns on treatment were evaluated on a glue-laminated Douglas-fir pole. While some differences were noted in the patterns, the pole was too well-treated to permit effective separation of the various patterns. The air-seasoning studies are now completed. Evaluation of the final pahse of this study showed that decay fungi began to colonize the pole sections after only 3 months of air-seasoning. Examination of weather data failed to provide a conclusive relationship between climate and colonization, possibly due to the array of variables to which the seasoning wood is subjected. The test suggests that most poles are adequately dried within three months of air-seasoning so that short air-seasoning exposures could be feasible. Sterilization at some point during the treatment cycle should still be considered as an integral part in the proper treatment of poles. Field trials to evaluate the performance of modified groundline wrap systems are continuing at both the Corvallis site and on a test line near Modesto, CA. The results at the Corvallis site indicate the copper naphthenate, boron, and fluoride are all moving well into the wood eighteen months after application. More controlled laboratory trials on one formulation suggest that the water soluble copper naphthenate can migrate for some distance into the wood within six months after application. As expected, wet wood permits more iv substantial diffusion. Evaluation of copper naphthenate treated western redcedar stakes in a fungus cellar suggests that the specified treatment levels are providing adequate protection, although some decay is occurring. Stakes which were obtained from weathered sapwood appear to be failing more rapidly those cut from freshly sawn lumber, possibly because the former stakes have a more open structure which permits leaching losses and subsequent fungal colonization. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1991 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 a diminishing level of protection to Douglas-fir poles. Tests of solid methylisothiocyanate (MITC), now in their thirteenth year, indicate that this chemical continues to prevent recolonization of Douglas-fir poles by decay fungi. MITC appears to provide equivalent or better protection than Vorlex. Gelatin encapsulated MITC and chioropicrin also continue to perform well in field trials. Although the gelatin is water soluble and must decompose to release the chemical, the addition of water to the treatment holes did not appear to significantly enhance long-term MITC performance. Laboratory trials to identify safer fumigants indicate that sodium nmethyldithiocarbamate decomposition occurs even in dry wood, although the rate of decomposition is enhanced by the presence of some moisture. A gelled 40 % NaMDC formulation has also been evaluated for its ability to eliminate decay fungi from Douglas-fir heartwood. This formulation has performed better than liquid metham sodium. Field trials are planned with both the solid and gelled NaMDC. Laboratory trials have also been performed to evaluate the toxicity of fused borate rods to Antrodia carbonica and Postia placenta. These two fungi are important decayers of Douglas-fir utility poles. The results indicate that the boron moved well through both wood species, but complete elimination of the test fungus required 6 to 8 weeks. Antrodia carbonica was generally more tolerant of boron than P. placenta. Field trials of fused borate rods indicate that the boron has moved downward from the point of application, but no evidence of upward movement was noted. Trials to evaluate the efficacy of glass-encapsulated M:[TC in Douglas-fir 1 11 and southern pine poles are now in their second year. The results continue to indicate the MITC levels are higher in Douglas-fir poles. The reasons for this descrepancy are unclear, but may reflect an increased MITC loss from the more permeable southern pine poles. Controlled studies of MITC release rates from the glass vials show that the tubes retain chemical for 1 to 2 years under normal conditions. Faster losses occur under more tropical conditions, while little loss occurs in cold conditions. Evaluations of additives to enhance Basamid decomposition in Douglas-fir pole sections indicate that the presence of copper sulfate and pH 12 buffer markedly improve the rate of decomposition to MuG one year after chemical application. More controlled laboratory studies are underway to better understand this effect. The trials to evaluate the effects of voids on fumigant movement continue to indicate that the void has little effect on chemical concentration. These results indicate that fumigant treatment of poles with voids is feasible provided the wood retains adequate strength. Laboratory trials to develop diffusion coefficients for chloropicri.n movement through Douglas-fir heartwood have been developed. As expected, chioropicrin movement was most rapid longitudinally and at the fiber saturation point. Drier wood retained more chemical, slowing diffusion. The diffusion coefficients will be employed in the fumigant model currently being evaluated on MITC. The model indicates that MITC movement was greatest at moderate moisture levels (22 or 44 %), while higher or lower moisture regimes limited chemical movement. The results obtained using the model will be confirmed through laboratory trials and by comparison with the results of chemical analyses performed on the glass-encapsulated MITC trials. The trials to identify potential replacements for pentachlorophenol for Ii' remedial treatments are continuing. A number of chemicals have been identified for both the protection of field drilled bolt holes and the spray treatment of western redcedar sapwood. Spray treatments of the most promising chemicals will be applied to western redcedar poles in service. The identification of small scale tests for detecting decay or estimating residual strength are continuing. We also continue to evaluate the effectiveness of various pretreatments for improving treatment and performance of poles. The effects of through boring and radial drilling patterns on treatment were evaluated on a glue-laminated Douglas-fir pole. While some differences were noted in the patterns, the pole was too well-treated to permit effective separation of the various patterns. The air-seasoning studies are now completed. Evaluation of the final pahse of this study showed that decay fungi began to colonize the pole sections after only 3 months of air-seasoning. Examination of weather data failed to provide a conclusive relationship between climate and colonization, possibly due to the array of variables to which the seasoning wood is subjected. The test suggests that most poles are adequately dried within three months of air-seasoning so that short air-seasoning exposures could be feasible. Sterilization at some point during the treatment cycle should still be considered as an integral part in the proper treatment of poles. Field trials to evaluate the performance of modified groundline wrap systems are continuing at both the Corvallis site and on a test line near Modesto, CA. The results at the Corvallis site indicate the copper naphthenate, boron, and fluoride are all moving well into the wood eighteen months after application. More controlled laboratory trials on one formulation suggest that the water soluble copper naphthenate can migrate for some distance into the wood within six months after application. As expected, wet wood permits more iv substantial diffusion. Evaluation of copper naphthenate treated western redcedar stakes in a fungus cellar suggests that the specified treatment levels are providing adequate protection, although some decay is occurring. Stakes which were obtained from weathered sapwood appear to be failing more rapidly those cut from freshly sawn lumber, possibly because the former stakes have a more open structure which permits leaching losses and subsequent fungal colonization. Close

• 70. [Article] Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1992

  Evaluation of previously established field trials of remedial internal treatments demonstrates the continued performance of chioropicrin, Vorlex, and methylisothiocyanate (MITC). While the degree of protection ...

  Citation × Citation Citation Abstract Copy Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1992 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluation of previously established field trials of remedial internal treatments demonstrates the continued performance of chioropicrin, Vorlex, and methylisothiocyanate (MITC). While the degree of protection afforded by these treatments has declined with time, residual fungitoxic levels remain in many tests. Field trials of gelatin encapsulated MITC indicate that gelatin had no negative effect on fumigant performance even when no water was added at the time of treatment. Closed tube bioassays, chemical analyses, and culturing of Douglas-fir and southern pine poles treated with glass encapsulated METC (MITC-Fume) indicate that this chemical is outperforming metham sodium 3 years after application. While the glass vials lost chemical very slowly, the slow release rate did not appear to adversely affect MITC performance. Trials to evaluate the performance of fused borate rods were sampled after 1 or 2 years of exposure. Chemical analysis of cores removed from the test poles revealed that none of the treatments contained boron at levels which would be considered adequate for arresting or preventing colonization by wood decay fungi. Interestingly, boron levels in poles exposed in Hilo, Hawaii were highest above the treatment hole, suggesting that some upward diffusion of this chemical is possible. The low boron levels in these poles are reason for concern, since a number of utilities are considering the using this formulation for remedial treatment at the groundline. Evaluations of new solid fumigants are progressing. Trials with Basamid indicate that the addition of copper compounds improved the rate of decomposition to produce MITC. Simultaneous addition of copper sulfate and Basamid may be useful for accelerating the decomposition of this compound, making it practical for control of internal decay fungi. Trials have been established to evaluate the performance of gelled and pelletized metham sodium and a sodium fluoride/boron rod. These trials will be evaluated in future reports. A third field trial to evaluate the performance of a copper naphthenate/boron paste for internal treatment of Douglas-fir poles is currently be evaluated to determine chemical levels 3 years after treatment. The performance of gelled metham sodium was further evaluated under laboratory conditions to better understand the performance of this chemical. Gelled metham sodium provided improved fungal control in comparison with liquid metham sodium and appeared to produce increased MITC levels under a variety of test conditions. The improved performance of this formulation may reflect the ability of the gell to retain moisture for longer periods of time than the liquid metham sodium formulation. Further studies of this formulation are underway. Laboratory studies were also performed to evaluate the effects of various additives on the performance of Basamid. Once again, the addition of copper compounds enhanced the production of MITC. A number of other compounds shifted decomposition to the production of carbon disulfide and carbonyl sulfide, two less fungitoxic compounds. Further studies are underway to identify non-sulfur products which may provide some protection against wood decay fungi. Evaluations of the effects of artificial voids on performance of fumigants in Douglas-fir poles indicate that voids had little or no effect on fumigant distribution. As a result, fumigant treatment of solid wood around voids represents a viable strategy for improving pole service life. Evaluation of timbers treated with metham sodium indicate that detectable levels of MITC were present one year after treatment. These timbers will be evaluated in subsequent years to determine the protective period provided by fumigants in sawn material. We continue development of a fumigant movement model using data previously developed on MITC. This year, we evaluated a previously developed system, ANSYS. Results of preliminary trials are similar to data previously developed on MITC-Fume treated poles and indicate that modeling MITC movement should be possible. Further trials are underway to confirm and expand this model. The effect of wood moisture content, temperature and wood species on metham sodium decomposition was investigated under laboratory conditions. The efficiency of dcomposition to MITC varied widely, but was most affected by temperature and wood moisture content. The results suggests that there is considerable potential for improving decomposition efficiency to enhance performance of this fumigant. Further studies to characterize the relationship between chemical content of the wood species and decomposition are underway. Field trials to identify safer treatments for preventing decay of cedar sapwood and protecting field drilled bolt holes are continuing. Diffusible treatments continue to provide excellent protection for field drilled bolt holes. A study to develop estimates of the extent of decay above the groundline in Douglas-fir poles in the Pacific Northwest is underway. The data from this study will be used to develop estimates of the potential for damage and provide some insight into the extent of this problem. Studies to develop guidelines for sterilization of Douglas-fir poles following air-seasoning are continuing. Evaluations of internal temperature development during kiln-drying were completed this year and indicate that internal temperatures during typical pole drying schedules were more than adequate for acheiving sterilization. Further evaluations of the data are underway to develop reliable heating curves for this process. Evaluations of groundline preservative systems have been established at Corvallis, OR and Merced, CA. The results indicate that all of the formulations are moving well through the wood in a manner similar to that found with pentachlorophenol-based systems. Chemical levels in some treatments; however, are beginning to decline 30 months after treatment. Studies are now underway to establish thresholds for combinations of the various formulations. Copper naphthenate treated western redcedar stakelets continue to perform well in fungus cellar trials. Stakes weathered prior to treatment are degrading slightly faster, while freshly sawn stakelets continue to perform well. Field trials have also been established to evaluate the performance of copper naphthenate treated Douglas-fir utility poles in California and Oregon. The chemical levels and fungal colonization will be monitored in these poles to provide a guide to performance of this chemical in western wood species. Title: Conserving energy by environmentally acceptable practices in maintaining and procuring transmission poles for long service ; August 1992 Author: Morrell, Jeffrey J., Oregon State University. Dept. of Forest Products, Corden, M. E. (Malcolm E.) Evaluation of previously established field trials of remedial internal treatments demonstrates the continued performance of chioropicrin, Vorlex, and methylisothiocyanate (MITC). While the degree of protection afforded by these treatments has declined with time, residual fungitoxic levels remain in many tests. Field trials of gelatin encapsulated MITC indicate that gelatin had no negative effect on fumigant performance even when no water was added at the time of treatment. Closed tube bioassays, chemical analyses, and culturing of Douglas-fir and southern pine poles treated with glass encapsulated METC (MITC-Fume) indicate that this chemical is outperforming metham sodium 3 years after application. While the glass vials lost chemical very slowly, the slow release rate did not appear to adversely affect MITC performance. Trials to evaluate the performance of fused borate rods were sampled after 1 or 2 years of exposure. Chemical analysis of cores removed from the test poles revealed that none of the treatments contained boron at levels which would be considered adequate for arresting or preventing colonization by wood decay fungi. Interestingly, boron levels in poles exposed in Hilo, Hawaii were highest above the treatment hole, suggesting that some upward diffusion of this chemical is possible. The low boron levels in these poles are reason for concern, since a number of utilities are considering the using this formulation for remedial treatment at the groundline. Evaluations of new solid fumigants are progressing. Trials with Basamid indicate that the addition of copper compounds improved the rate of decomposition to produce MITC. Simultaneous addition of copper sulfate and Basamid may be useful for accelerating the decomposition of this compound, making it practical for control of internal decay fungi. Trials have been established to evaluate the performance of gelled and pelletized metham sodium and a sodium fluoride/boron rod. These trials will be evaluated in future reports. A third field trial to evaluate the performance of a copper naphthenate/boron paste for internal treatment of Douglas-fir poles is currently be evaluated to determine chemical levels 3 years after treatment. The performance of gelled metham sodium was further evaluated under laboratory conditions to better understand the performance of this chemical. Gelled metham sodium provided improved fungal control in comparison with liquid metham sodium and appeared to produce increased MITC levels under a variety of test conditions. The improved performance of this formulation may reflect the ability of the gell to retain moisture for longer periods of time than the liquid metham sodium formulation. Further studies of this formulation are underway. Laboratory studies were also performed to evaluate the effects of various additives on the performance of Basamid. Once again, the addition of copper compounds enhanced the production of MITC. A number of other compounds shifted decomposition to the production of carbon disulfide and carbonyl sulfide, two less fungitoxic compounds. Further studies are underway to identify non-sulfur products which may provide some protection against wood decay fungi. Evaluations of the effects of artificial voids on performance of fumigants in Douglas-fir poles indicate that voids had little or no effect on fumigant distribution. As a result, fumigant treatment of solid wood around voids represents a viable strategy for improving pole service life. Evaluation of timbers treated with metham sodium indicate that detectable levels of MITC were present one year after treatment. These timbers will be evaluated in subsequent years to determine the protective period provided by fumigants in sawn material. We continue development of a fumigant movement model using data previously developed on MITC. This year, we evaluated a previously developed system, ANSYS. Results of preliminary trials are similar to data previously developed on MITC-Fume treated poles and indicate that modeling MITC movement should be possible. Further trials are underway to confirm and expand this model. The effect of wood moisture content, temperature and wood species on metham sodium decomposition was investigated under laboratory conditions. The efficiency of dcomposition to MITC varied widely, but was most affected by temperature and wood moisture content. The results suggests that there is considerable potential for improving decomposition efficiency to enhance performance of this fumigant. Further studies to characterize the relationship between chemical content of the wood species and decomposition are underway. Field trials to identify safer treatments for preventing decay of cedar sapwood and protecting field drilled bolt holes are continuing. Diffusible treatments continue to provide excellent protection for field drilled bolt holes. A study to develop estimates of the extent of decay above the groundline in Douglas-fir poles in the Pacific Northwest is underway. The data from this study will be used to develop estimates of the potential for damage and provide some insight into the extent of this problem. Studies to develop guidelines for sterilization of Douglas-fir poles following air-seasoning are continuing. Evaluations of internal temperature development during kiln-drying were completed this year and indicate that internal temperatures during typical pole drying schedules were more than adequate for acheiving sterilization. Further evaluations of the data are underway to develop reliable heating curves for this process. Evaluations of groundline preservative systems have been established at Corvallis, OR and Merced, CA. The results indicate that all of the formulations are moving well through the wood in a manner similar to that found with pentachlorophenol-based systems. Chemical levels in some treatments; however, are beginning to decline 30 months after treatment. Studies are now underway to establish thresholds for combinations of the various formulations. Copper naphthenate treated western redcedar stakelets continue to perform well in fungus cellar trials. Stakes weathered prior to treatment are degrading slightly faster, while freshly sawn stakelets continue to perform well. Field trials have also been established to evaluate the performance of copper naphthenate treated Douglas-fir utility poles in California and Oregon. The chemical levels and fungal colonization will be monitored in these poles to provide a guide to performance of this chemical in western wood species. Close