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Effect of cyclic change of temperature on fungal growth and mass loss
1994 - IRG/WP 94-10065
For estimating the effect of cycling change of temparature on fungal growth, four Japanese species, sugi (Cryptomeria japonica), hinoki (Chamaecyparis obtusa), akamatsu (Pinus densiflora) and buna (Fagus crenata), four fungal species, Tyromyces palustris, Gloeophyllum trabeum, Coriolus versicolor, Pycnoporus coccineus, and five temperature conditions, 10, 20, 27, 35°C and cyclic temperature (20°C 12 hours and 30 or 27°C 12 hours) under constant humidity (75% RH) were examined. The results were summarised that the cyclic condition was rather high fungal growth rate in the case of majority of fungi tested but was not surely increased the mass loss of wood. This tendency is rather clear in the case of brown rot like Tyromyces palustris. The cyclic temperature conditions were not favorable to the groth of Serpula lacrymans.
K Suzuki, K Okada


Effects of acetylation on the dimensional stability and decay resistance of kenaf (Hibiscus cannabinus L.) fiberboard
1996 - IRG/WP 96-40059
The objective of this study was to investigate the influence of the acetylation treated kenaf fiber, Phenol formaldehyde resin content level, and three fungi species on the dimensional stability and decay resistance of high density non wood composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness, length changes, and decay resistance of the high density kenaf fiberboards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Rowell


Combined effects of the treatment of wood with formaldehyde
1978 - IRG/WP 3117
Treatment of fibrous materials with reagents in a vapor phase is neither new nor unique. Numerous examples exist in literature of vapor phase experiments on cellulose fibers and fabrics, and on wood. For many years the textile research and industry have used vapor phase processes for the treatment of textiles. The chemical modification of cellulose is based on different types of reactions e.g. esterification, alkylation, resin formation or polymerization, monomer grafting and crosslinking. Vapor phase treatment of wood offers certain potential advantages over the conventional liquid phase wood impregnation. The higher mobility of low molecular weight compounds in the gaseous state ensures a rapid, uniform and homogeneous distribution throughout the wood structure. The vapor phase treatment of wood is also a better approach from the standpoint of cell wall penetration. Bulking, which takes place in the cell wall only, means that less chemicals are required and that the final weight of the composite is limited. Furthermore, due to the low viscosity of a gas, the application of a lower pressure differential remains possible. Within the framework of a wood improvement programme carried out at the Laboratory of Wood Biology and Wood Technology (University of Ghent, Belgium) the treatments were based on the impregnation of wood with liquid synthetic monomers and with gaseous formaldehyde. The results of the hygroscopic and dimensional behaviour of the wood-plastic-combinations have been published previously. Other papers deal with the physical and chemical interactions between the synthetic products and the natural polymers of the cell wall. This contribution will be restricted to the treatment of wood with formaldehyde in the gaseous state.
M Stevens, J Schalck


Biodegradation of acetylated southern pine and aspen composition boards
1994 - IRG/WP 94-40020
This objective of this study was to investigate the influence of the acetylation treated wood fiber, Phenol-formaldehyde resin content level, two wood fiber species, three fungi species on the dimensional stability and decay resistence of high density composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness and length changes and the decay resistance of the high density composition boards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Powell


Effects of boron treatments on partially decayed oak and pitch pine heartwood
1996 - IRG/WP 96-30106
This paper reports results of borate based preservative treatment and leaching experiments on partially decayed oak and pitch pine heartwood. Previous experiments have shown little damage is caused to sound timber of these types when treated with Polybor and Boracol 20 preservatives. This experiment was carried out to assess the suitability of selected borate based preservatives for use in historical ships' timbers and therefore the physical effects of these preservatives on such timber was investigated. The results indicate that weight losses incurred due to treatment with Polybor or Boracol 20 are no more damaging than those incurred by treatment with water. Weight changes were more apparent in decayed timber than in sound timber with greater uptakes in non-leached samples and greater weight losses in leached samples. However, comparable weight changes were recorded between water treated samples and preservative treated samples. Dimensional changes were minimal in most cases, the greatest found in non-leached Boracol 20 samples as expected. These results indicate that treatment with these preservatives is suitable for partially decayed oak and pitch pine heartwood.
S McCutcheon, G M Smith, J W Palfreyman, P Durrant


Steam/hold/APM boron treatment - Treatability trials with green gauged radiata pine
1987 - IRG/WP 3439
Freshly sawn 100 x 50 mm radiata pine was green gauged, steam conditioned and preservative treated with a mixture of borax and boric acid using a modified Alternating Pressure Method (APM) treatment schedule. A 12 hour holding period between steam conditioning and treatment resulted in the necessary moisture loss and moisture re-distribution to facilitate treatment to NZ Timber Preservation Authority preservative retention and distribution requirements.
P Vinden


The impact of global warming on the UK distribution of house longhorn beetle Hylotrupes bajulus (L)
2001 - IRG/WP 01-10414
This paper reviews the effects of global warming on insect populations and distribution. The affects of global warming on the spread of Hylotrupes is predicted through a review of research related to the influence of temperature on its life-cycle and flight. Records of Hylotrupes distribution were obtained from published surveys, entomologists and museum collections and were plotted for the UK. The UKCIP98 model for climate change was then used to present the average maximum daily temperatures over the emergence period at present, and in the future. The model predicts a 3°C rise in annual temperature by the 2080's. This increase may enable mated females to fly on a greater number of days and over a greater area. The discussion highlights gaps in knowledge concerning the UK population that makes rate of spread difficult to predict at present.
P Oevering, A J Pitman


Cyclic delamination analysis of preservative-treated wood/FRP interfaces
2002 - IRG/WP 02-40244
Wood preservative chemicals can interfere with adhesive properties when bonding wood laminates or wood/FRP (Fiber Reinforced Polymer) laminate composites. In this work we studied the effects of various wood preservative treatments, and pre- and post-treatment on wood/wood and wood/FRP bond durability using a severe cyclic delamination test (ASTM D-2559). Pre-treatment of individual laminates with oil-borne (copper naphthenate, creosote and pentachlorophenol) and water borne (CCA and CDDA) preservatives increased the delamination between the wood and FRP, although wood/wood bonds were generally acceptable. Post-treatments had limited effect on wood/wood delamination. The use of post-treatments on wood/FRP bonded samples, although less significant than with pre-treatments, also increased delamination of wood/FRP glue lines.
C Tascioglu, B Goodell, R Lopez-Anido


Preliminary investigation on the natural durability of Guayule (Parthenium argentatum)-based wood products
2000 - IRG/WP 00-40154
Conventional preservatives used to protect wood from insect and microbial damages are presently of major concern to human health and the environment. Finding alternative and economical preservatives has not been successful. Previous studies have shown that the resinous material extracted from the guayule plant (Parthenium argentatum, Gray) has both insect- and microbial-resistant properties. Unfortunately, it has not been accepted commercially because of the lack of an adequate supply of the raw material. However, the potential domestication of the guayule plant to produce hypoallergenic rubber latex will result in the production of large amounts of waste wood material. This should provide opportunity to use this natural source of the biologically resistant resinous chemicals. The objective of this preliminary study was to determine the effects of the rubber latex-removed wood residues or bagasse and the resinous extracts on termite- and decay-resistant properties. Two types of test materials were used in the study. One was wood impregnated with organic-solvent extracted resinous material from the plant. The other was composite wood fabricated using the residue or whole plant and plastic binder, which was used to improve the physical properties of the composite. Accelerated laboratory tests were conducted to determine the resistance of the wood products against the Eastern subterranean termite and wood fungi (brown-rot). The wood and stem of the guayule plant, wood treated with the resinous extract, and particle and composite wood made from ground guayule exhibited termite and wood fungal resistance.
F S Nakayama, P Chow, D S Bajwa, J A Youngquist, J H Muehl, A M Krzysik


The effect of oil-borne preservative treatments on the shear strength of FRP/wood composite adhesive bonds
2003 - IRG/WP 03-40265
Reinforcement of structural wood components with Fiber Reinforced Polymer (FRP) will enhance the beam’s strength, but actual data on long-term durability is sparse, not well documented or not readily accessible. In this study, bond properties of FRP-wood composite materials were investigated following treatment with creosote or copper naphthenate preservatives. The properties investigated included stress and the percentage of wood failure experienced in shear (ASTM 1998). When tested in a wet condition (following a vacuum/pressure soak), creosote-treatment adversely affected the wood failure values associated with specimens fabricated with a pultruded FRP composite sheet (E-glass fiber, bonded with urethane). When these tests were conducted with samples under ambient conditions, the shear strength of this material was also adversely affected by creosote. In addition, both creosote- and copper napthenate-treatment adversely affected the shear strength of a SCRIMP™ fabricated FRP material (carbon fiber, vinyl ester matrix).
B Herzog, B Goodell, R Lopez-Anido


A New Decay Hazard Map for North America Using the Scheffer Index
2008 - IRG/WP 08-10672
Wood decay experts in the USA and Canada use the Scheffer Index for above-ground wood decay potential to decide among design and treatment options to ensure the durability of wood construction. This paper provides an updated North American decay hazard map and includes data on Central America. Index values calculated from recent climate data are higher than published values due to directional or cyclical climate change. Compared to previously published maps there is considerable expansion of the moderate decay hazard zone in the interior wet belt of British Columbia, across the northern edge of the Prairies and around the Gulf of St. Lawrence. This suggests a greater need for preservative treatment in these parts of Canada.
P I Morris, J Wang


Anatomical, physical and chemical changes of Bamboo (Phyllostachys puberscence ) during weathering processes
2008 - IRG/WP 08-10650
Bamboo (Phyllostachys puberscence) culms with 1, 2, 3 year old were exposed to natural weathering condition in Gwangju, Korea for 12 months. Changes in color, surface topography, strength and chemical properties were investigated using various microscopic and instrumental techniques. After one year’s weathering, the color of bamboo became lighter but strengths of bamboo did not change significantly. Depending upon the age of bamboo culms, the rate of the check development and the surface erosion were different. Numerous checks were developed in the 2 and 3 year old bamboo whereas little checks in the 1 year old bamboo were appeared. Regardless of bamboo age, most of parenchyma cells in the ground tissues were degraded and lignin was rapidly decreased at initial period of weathering, although structural polysaccharides were also degraded by weathering.
Jong Sik Kim, Kwang Ho Lee, Mi Young Cha, Yoon Soo Kim


Surface color and roughness characteristics of medium density fiberboard (MDF) panels treated with fire retardants
2008 - IRG/WP 08-40420
The objective of this study was to determine surface characteristics and color change properties of Medium Density Fiberboard (MDF) treated by fire retardants (FR) with 10% concentration. Experimental panels were made using by melamine ureaformaldehyde (MUF) adhesive having 10%, 15%, 20% of melamine. The surface properties of the samples were determined using a fine stylus technique. Three roughness parameters, namely average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) were determined from the surface of the samples. Color change properties of MDF samples were evaluated to CIE L*a*b* methods by a spectrophotometer (Minolta CM-2600d). It was found that the surface roughness values of the FR treated MDF panels were higher than those of control panels. The highest surface roughness values obtained from MDF panels treated with MAF+BA+NPB, MAF+BA+BX, the lowest values obtained from MDF panels treated with MAF+AL. Also surface roughness of the MDF panels improved with increasing melamine additive rate in the MUF adhesive. According to CIEL*a*b method, color change properties of the samples showed variation as function of chemicals type. Especially, while the highest color change(?E) were determined for MDF samples treated with MINPB and MAF+BA+NPB, the lowest color change (?E) were obtained from MDF samples treated with MAF+AL, MIN.
D Ustaömer, M Usta, S Hiziroglu


Wood protection, a tool for climate change mitigation?
2008 - IRG/WP 08-50257
In the context of global warming and the search for possible strategies to mitigate climate change, forest and forest products have important advantages. Sustainable management makes forest a carbon sink, wood products have the potential to be a carbon sink as well, and their low carbon intensity is a potential for reducing CO2 emissions by substitution to competing materials. After describing these assets of wood products, this paper analyses how wood protection can reinforce them. This reinforcement effect is probably important, but still needs to be quantified.
G Deroubaix


Effectos de la intemperización artificial sobre la madera de mezquite (Prosopis laevigata)
2008 - IRG/WP 08-40430
The effects of artificial weathering on Prosopis laevigata wood were studied on eight replicates (150 x 72 x 15mm (l x t x r)) free of knots, cracks and resin. The samples were exposed tangentially to UV light and to water spray during three cycles (1 cycle corresponded 1 week of artificial weathering). The conditioning time between each cycle was thirty days. The effects were measured according to visual appearance, crack formation, and colour changes; the results were then compared to two other well known timber species, namely teak (Tectona grandis) and beech (Fagus sylvatica). The specimens displayed changes in colour after three cycles of exposure. P. laevigata changed from brown to white. Delta C (Delta colour) increased from 5.6 to 9.6. There was less crack formation than in F. sylvatica but more than in T. grandis. Lightness was reduced from 61 to 37 after the first cycle; the lightness value of 35 was maintained at the end of the second and third cycles. The P. laevigata specimens showed several changes in colour after artificial weathering. The Delta C was higher due to the photodegradation of lignin and phenolic compounds caused the UV light and the leaching caused by water.
A Carrillo-Parra, F Hapla, C Mai


Accelerated weathering of nine tropical wood species from Cameroon
2009 - IRG/WP 09-10705
The natural durability of tropical species for building components has been a subject of recent concern and questioning, mainly the resistance to weathering. Weathering resistance of nine tropical species from Cameroon, namely Azobe, Bilinga, Bubinga, Teak, Dousie, Moabi, Musanga, Sipo and Padauk were evaluated using an accelerated weatherometer for 2016 hours. Measurement of moisture fluctuation, weight loss, color change, and surface texture were taken at regular intervals of time. It was found that the weight loss, surface roughness and color change increased with the exposure time of samples to accelerated weathering conditions as compared to the initial property at the beginning of the test. The amount of weight loss during the testing increases with the amount of moisture fluctuation in samples during the test. Moisture fluctuation in sample during weathering was related to the weight loss of weathered samples indicating that the moisture fluctuation may be an indicator of durability. The lowest weight loss and water absorption were observed with Azobe, Padouk, Teak, Doussie and bilinga whereas highest weight loss were obtained for Moabi and Musinga. For color change, reddish, brownish, yellowish colored species such as padouk, Doussie, bilinga exhibit high values of color change parameter in comparison toMussanga light whitish colored species. .
S Pankras, Jinzhen Cao, D P Kamdem


Colour change monitoring of photodegradation in Scots pine (Pinus sylvestris) – a short term focus
2009 - IRG/WP 09-40442
Colour change monitoring of photodegradation is a quick and easy method for monitoring rates of photodegradation in timber. A study was undertaken to compare this technique to other monitoring methods, including microtensile strength changes and weight loss. Colour changes due to accelerated sunlight exposure were monitored using a Datacolor check spectrophotometer and compared with a set of controls. Measurements on both samples and controls were performed hourly for the 1st 24 hours and there after daily until 168 hours’ exposure with extra measurements at 200, 350 and 500 hours. A subset of samples, were extracted prior to exposure to check the effects of any colour change due to the presence of extractives. Data was analysed using the reflectance spectra (400-700nm) as well as the CIE-L*a*b* system and ΔE. The majority of colour changes were found to occur within the 1st 24 hours. This was unaffected by the removal of extractives from the wood and was independent of temperature. When compared to the other monitoring methods, colour monitoring has been shown to be the most sensitive method out of the methods compared for monitoring photodegradation in Scots pine.
V Sharratt, C A S Hill, D P R Kint


Termite taxonomy and distribution with particular reference to climate change in Africa
2010 - IRG/WP 10-10738
Termites constitute an integral component of various ecosystems in Africa. Termites are also amongst the most difficult of the insects to study because of their cryptic behaviour. There are around 2600 species of termites (Isoptera) in 280 genera which have been described worldwide and about 39% of the total termite species are found in Africa. Some termite species are well known pests of agricultural crops, forest trees, wood products and timber-in-service. Thus, they are responsible for considerable damage in building structures in Africa. Termite identification is crucial to understanding termite distribution and to develop an integrated termite pest management (IPM) system. Published literature on the taxonomy and distribution of termites in Africa with particular reference to climate change is scanty. Little is known about the effect of climate change on the potential distribution of pestiferous termite fauna of Africa, especially the wood destroying exotic species. This African termite review attempts to collate information on termite taxonomy, distribution and climate change and highlight the gaps in knowledge and challenges in Africa, which is the centre of origin of the Macrotermitinae. African economic important termite species will receive sufficient attention for identification and distribution compared to other termite species. The use of traditional identification methods coupled with molecular techniques promises to resolve some of the challenges in termite taxonomy and distribution with particular reference to climate change in Africa, will be discussed.
P O Y Nkunika, B M Ahmed Shiday, G W Sileshi, J R J French, P Nyeko, S Jain


Impact of climate change on wood deterioration - Challenges and solutions for cultural heritage
2010 - IRG/WP 10-20441
Deterioration of wood in cultural assets follows the same physiological mechanisms as in modern structures. Therefore rules and data for prediction of service life derived from old wooden structures can be used to model the service life of recent wooden structures and vice versa. The latter is done in this paper: From experimental test set ups in the field spread over Europe, climatic data, wood temperature, wood moisture content, and decay rates recorded for several years were correlated and used for mathematic modelling of decay. On that data basis a first attempt is made to quantify the influence of global warming on wood decay rates for different regions and scenarios, valid for both: wood in modern and historic structures. Against this background conservation of cultural heritage is increasingly challenging and methods are sought to allow historic structures to survive without severe modifications in design, but also with limited use of preservatives. How moisture monitoring can contribute to this purpose is shown on the example of the Echo pavilion in Maksimir Park, Zagreb, Croatia.
C Brischke, A O Rapp, M Hasan, R Despot


Comparison of colour change in wood clear-coating systems including inorganic and organic UV absorbers for exterior use
2010 - IRG/WP 10-40499
The aim of this work is to compare the performance of inorganic and organic UV absorbers used in a wood coating application against weathering. Our study has investigated the colour changes of selected UV absorbers; hombitec 402 RM from the Sachtleben Company as an inorganic UV absorber, tinuvin 477 DW from the Ciba Company as an organic UV absorber. The study was carried out on two wood species; Fagus sylvatica L., Pinus sylvestris L. The results obtained after 28 days (672h) of accelerated weathering showed that the colour stability was the same for hombitec 402 RM and tinuvin 477 DW and both systems showed a significant improvement of colour stabilization compared to the control samples. In addition, the wood surface from cracks was protected with the clear-coat containing both of UV absorber.
Ö Özgenç, B Forsthuber, A Teischinger, C Hansmann


Climate change and wood protection, increasing demand of long life wood products and decreasing production of treated wood
2010 - IRG/WP 10-50269
Several new topics related to wood protection sector has appeared in Japan, as the awareness of climate change becomes bigger and bigger. The “Basic act for housing (2006)” and the “Long-life housing promotion act (2009)” were enforced to form a safe and high quality housing stock and to form a long-service-life housing respectively. Despite of the favorable background for wood protection sector, the amount of treated wood was steadily decreasing to 202,057 m3 till 2008 from the maximum of 445,689 m3 in 1996 (JWPIA: Japan Wood Preservers Industry Association statistics). The discussion in this presentation is how the wood protection sector in Japan combats the climate change through the establishment of appropriate wood protection system. Several keywords are exterior wood products which can improve the landscape of housing area, treated wood products which can decrease the construction cost of house/year from prolonged service life of housing, local wood products which can mitigate climate change through lower embedded energy of sustainable local resources. It also requires integrated strategy to realize the increased utilization of these wood products.
K Yamamoto, H Kato


Effects of global climate change on mould growth - Interactions of concern
2010 - IRG/WP 10-50270
An evident change in climate the last decades has been recorded, and combined effects of increased CO2, elevated temperature and altered precipitation regimes have been observed to represent a change to the fundamental drivers within ecosystems. Growth of moulds, both in nature and on man-made constructions and objects, will most likely increase due to changes in the climate. The survival, the reproduction, the dispersal and the geographic distribution of moulds are decided by both direct and indirect effects of climate change. Not only the moulds, but also their hosts and substrates, possible competitors and enemies will be affected by climate change. It is essential to understand the interactions between the members in these ecosystems to be able to control and predict future development of moulds. The effect of introducing new building directives, environmental friendly materials and products which are meant to oblige the demand for more climate friendly buildings and houses, is an aspect that may generate unexpected and unintended mould growth on man-made constructions and objects. Future research should focus on the interaction between the moulds, the hosts, the substrates and the climatic factors, and what implications future changes in building directives and housing policy will have on mould growth.
L Ross Gobakken


The assessment by visual grading, change of color and ergosterol content ratings, the resistance to mould fungi of treated with wood preservative Scots pine sapwood
2013 - IRG/WP 13-20514
The filamentous (mould) fungi belonging to Ascomycetes, Deuteromycetes group are an cosmopolitan organisms which attacks wooden elements disfiguring them, dropping their value and causing environmental and health hazard. The fungi in a short time cause mainly disfigurement of wood does not effect on strength properties of wood, but with strong prolongation of duration of conditions favourable for their growth, some of them may cause even soft rot of lignocelluloses materials. The using of fungicides is one of the easiest methods to protect wood and other susceptible wood-based materials against mould fungi attack. So, good recognition of natural or given resistance of wood to mould fungi may be regard as important matter. There are some, mainly descriptive, laboratory methods for susceptibility of wood to mould fungi attack determining, however there are not European standards concerning the method. The aim of the research was an attempt of comparison of standard visual grading of mould fungi growth on wood surface with results of instrumental measuring of changes in wood colour and ergosterol content in wood resulting from the fungi growth. The samples of natural and treated with a model wood preservative Scots pine sapwood were the examples of tested materials. The test and control samples were exposed to the individual fungi: Aspergillus niger, Penicillium funiculosum, Paecilomyces variotti, Trichoderma viride, and Alternaria tenuis, and their Mixture (Set I) or set II: Chaetomium globosum fungus. It was observed that results of determinations of ergosterol concentration, seems to be between used methods more detailed and to show even greater differentiation of wood infestation grades than the evaluation based on the descriptive methods. The evaluation of wood infestation by fungi which was based on the measurements of colour changes of wood surface were also more detailed as visually evaluation, but the differentiation of wood infestation grades was not so distinct. The results of the instrumental measurement of the growth of mould fungi on wood may be considered at the moment as supplement to descriptive evaluations expressed in grades of fungi growth. Ergosterol content determination after further investigations may be an alternative to descriptive evaluations.
A Fojutowski, A Koziróg, A Kropacz


Study of UV resistance and natural weathering of coatings on chemically modified wood
2013 - IRG/WP 13-40629
In this study, UV resistance and weathering performance of rubberwood (Hevea brasiliensis) and radiata pine (Pinus radiata) modified with benzoyl chloride and acetic anhydride was studied. Performance of polyurethane based wood coatings on modified wood was also evaluated. Unmodified and chemically modified specimens were exposed to accelerated and natural weathering. Modified and unmodified wood specimens were coated with commercially available polyurethane based transparent and opaque finishes and exposed to natural weathering for a period of 2 years. Physical and chemical deteriorations on uncoated / coated wood panels due to weathering were periodically monitored. Analysis of colour changes and chemical deteriorations of weathered specimens showed rapid discolouration and lignin degradation on unmodified wood surface exposed to weathering. Modified wood showed resistance to weathering and was partially effective in inducing UV resistance as compared to unmodified wood. Results clearly indicate that performance of coating can be significantly improved by chemically modifying wood substrate with benzoyl chloride. Benzoylation of wood polymers improved coatings adhesion and enhanced life of paints by 3-4 times. The performance of opaque coating was better than transparent coating, presumably due to photodegradation of wood substrate in transparent coating.
K K Pandey, K Srinivas


Is there a role for termite alates in colony expansion in Wisconsin?
2014 - IRG/WP 14-10820
Termite colonies in Wisconsin tend to be large and widely spread out geographically, and separated by distances up to 1342km. We recently completed a study to determine the genetic diversity and population substructure of thirteen existing colonies of Reticulitermes flavipes using amplified fragment length polymorphism to determine patterns of termite dispersal in Wisconsin. Measures of inbreeding, heterozygosity, genetic variation, polymorphism and geographic distances showed that colonies had mixed characteristics of what was expected for colony expansion through budding versus multiple introductions at physically separate sites by means of alates or human movement of infested materials. Overall, these results did not provide evidence of colonies formed by alate breeding pairs. Instead, we hypothesize that R. flavipes is likely spread by anthropogenic means, including discarded rail ties, in Wisconsin. Nearly all known areas of termite activity in the state lie on or near major rail lines. A new generation of dual-treatment of crossties with water soluble borates overcoated with a second treatment of water insoluble (oil borne) copper napthanate or creosote may begin to limit transfer of insect colonies via Interstate commerce.
F Green III, R A Arango, G R Esenther, T G Shelton


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