Your search resulted in 77 documents. Displaying 25 entries per page.
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
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
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.
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
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
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
Outbreak of timber pest in Philippines: A consequence of frequent typhoons
2019 - IRG/WP 19-50348
Evidence of climate change and its impact are now visible in many parts of the world. This report presents impact of natural disasters in particular typhoons on trees as it passes across the Philippines archipelago every year. Typhoons damage and destroy large number of trees which soon rot under moist and warm conditions. Wood beetles and termites find these sources very quickly, breaking down the dead trees. While doing so the pests establish new and healthy population in and around the devastated sites. Often events like these lead to pest build-up and lead to outbreak condition. This report presents a preliminary evaluation on pest density of two tree pests such as mound building termite Macrotermes gilvus and Rhinoceros beetle, Oryctus rhinoceros after Typhoon Hainan in 20013 and their control strategies.
Durability and climate change - implications for wood building structures
2019 - IRG/WP 19-50361
Sustainable building practices are rooted in the need for reliable information on the long-term performance of building materials; specifically, the expected service-life of building materials, components, and assemblies. This need is ever more evident given the anticipated effects of climate change on the built environment and the many governmental initiatives world-wide focused on ensuring that structures are not only resilient at their inception but also can maintain their resilience over the long-term. The Government of Canada has funded an initiative now being completed at the National Research Council of Canada’s Construction Research Centre on “Climate Resilience of Buildings and Core Public infrastructure”. The outcomes from this work will help permit integrating climate resilience of buildings into guides and codes for practitioners of building and infrastructure design. In this paper, a brief overview is provided of the broad objectives of this initiative with emphasis on buildings, and a description of methods that will allow practitioners to design new, or retrofit existing, buildings for climate resiliency. The implications for the design of wood building structures in respect to durability and climate change are considered in light of previous work undertaken on establishing the service life of wood structures. Information is provided on current research programs on this topic and on guides and standards developed in support of this initiative.
Observed and projected changes in the climate based decay hazard of timber in the United Kingdom
2020 - IRG/WP 20-20665
The risk of microbiological attack on wood is determined by both material and climatic factors and indeed the hazard for a component is based on its intrinsic durability and the conditions in which it is used. The use of wood and organic materials in construction is increasing but ultimately all these materials will be susceptible to microbiological attack. The Scheffer Climate index applies climatic variables such as temperature and wetting time to assess hazard zones within geographical areas. A changing and variable climate e.g. an increase in heavy but short duration rain events, may have an effect on the incidence or severity of microbiological attack and with the increase in the use of timber this could have significant impact on buildings and construction. This paper shows a significant increase in the Scheffer climate indices for various locations of the UK from 1990 to 2019. The highest index values are seen in the Northern and western areas of the United Kingdom, but increases are seen across the country. The paper also uses representative concentration pathway (RCP) scenarios to project future climate decay indices for the United Kingdom until the end of the 21st century. The projections show a significant increase in the climate decay index even in the lowest RCP scenario, with all regions of the UK moving to index values indicating a very high hazard based on climatic conditions
S F Curling, G A Ormondroyd
Assessing the risk of marine borer attack of the timber trestles and decay of timber above the intertidal zone of the Barmouth Viaduct
2021 - IRG/WP 21-10974
The Barmouth Viaduct is a Grade II* listed structure which carries the single track of the Dovey Junction to Pwllheli line and footway over the Mawddach estuary. It is in a marine environment where timber below the high tide mark is at most risk in Use Class 5 and all timber above in Use Class 3.2, permanently exposed to the risk of wetting. The structure consists of a timber trestle viaduct of 113 timber spans with 5 steel spans over the deep-water channel. It is of historic importance and is the longest functioning timber viaduct in the UK and is a vital link on the Cambrian line. However, the structure is ageing and under attack from a number of biological agents. Within the intertidal zone, the structure is at risk of attack by shipworm. Above the intertidal zone, the structure is permanently at risk of attack by wood decaying fungi. The structure is undergoing a £20 million refit with much of the work focussing on the renewal of timber that has been attacked by biological agents. The combination of an ageing infrastructure and stressed maintenance budgets provides the impetus to develop innovative methods to support the asset management plan of the structure. Understanding the performance of materials and their rates of deterioration may inform design choices. Moreover, understanding the impact of climate change and local environmental factors and how this can change the distribution of marine borers and affect the risk of decay can also support the long-term asset management of the viaduct.
J R Williams
Introduction to the project ‘Deterioration and decay of wooden cultural heritage in Arctic and Alpine environments’ (ArcticAlpineDecay)
2022 - IRG/WP 22-10997
The Arctic is already affected by climate change, and this is expected to accelerate over the coming decades. Alpine regions in Norway are projected to face similar challenges. Current knowledge on Norwegian wooden cultural heritage in Arctic and Alpine regions is scattered and contains significant knowledge gaps. Historically, - scientists, sectorial governance, tourist trade and commerce have mainly worked from their own expertise and experience regarding wooden cultural heritage in Arctic-Alpine regions. Hence, the challenges wooden cultural heritage in Arctic-Alpine regions are facing urgently need an integrated cross-disciplinary approach. This communication paper gives a short background and an introduction to the project ArcticAlpineDecay. The project ArcticAlpineDecay will use state-of-the-art methods within different areas of expertise, and the novelty of the newly started project is the expected synergy of combining information from different methodologies. We also expect synergy with two ongoing Norwegian projects, CULTCOAST and PCCH-Arctic, and these projects are therefore also briefly described.
G Alfredsen, L Ross, A W Hegnes, M S Austigard, J Mattsson, N B Pedersen, A Sinitsyn, V V Martens, A-C Flyen
The influence of climate changes on Central European forests with an emphasis on Slovenia
2022 - IRG/WP 22-50368
When forests are managed sustainably, they play an essential role in protecting climate and biodiversity. They protect soils and water resources, provide livelihoods, and contribute to the well-being of rural and urban communities. European forests are multifunctional and provide a range of ecosystem services. These include the production of renewable materials that can replace materials with a larger environmental footprint, thus also contributing to climate neutrality and overall sustainability. Forestry is one of the key sectors capable of reducing dependence on non-renewable resources, mitigating climate change, and thus enabling the transition to a circular bioeconomy. At the same time, forest ecosystems worldwide face a number of threats that are exacerbated by climate change. Global warming will affect future species distribution, timber supply and wood properties (quality). Conservation and management of forest genetic resources, the base of forest biodiversity and productivity, is an essential component of sustainable forestry. In addition, sustainable forestry requires a constant and efficient supply of high-quality seed and seedlings of forest trees. With a high share of forest cover and abundant natural resources, Slovenia shows great potential for transition into a circular bioeconomy. Due to the impact of climate change, recognition of the importance of biodiversity and the concepts of sustainable forest management, changes in the species composition of Slovenian forests are expected in the near future, which will be reflected in a higher proportion of deciduous tree species, affecting all actors in the forest-wood value chain. This paper aims to highlight up-to-date facts about the state of forests in Europe, forests and forestry in Slovenia, the importance of sustainable forest management for forest-based climate change mitigation and adaptation, the role of forest genetic resources and provision of tree seeds and seedlings for sustainable forest development.
J Gričar, L Krajnc, M Westergren, S Rus, H Kraigher
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
A proposal for an international wood preservation standard
1994 - IRG/WP 94-20031
Two factors are driving the need for an international wood preservation standard. First, the global need to use our natural resources more wisely and second, the movement towards free trade exemplified by the General Agreement on Tariffs and Trade. The International Research Group on Wood Preservation is the ideal organisation to undertake the task of developing such a standard. This paper is intended to start this process. It attempts to bring together the best points of a number of national and international standards into a uniform format. Preservative penetrations and retentions for each commodity would be based on the hazard class/use category, the climate zone, the biological area, the natural durability of the heartwood of the species used, the service life required and the consequences of failure. The outline standard presented borrows heavily from the new European Standard and is presented as a possible starting point for the development of an international standard.
P I Morris
Moulds and indoor climate in Denmark
2003 - IRG/WP 03-10488
Just like in many other countries after the oil crisis in 1972 Danish houses were tightened with the result that the relative air humidity rose considerably. The Ministry of Energy also demanded a lowering of the indoor temperature from 25°C to 20°C with the result that the relative air humidity rose even more. According to the latest survey 10% of Danish buildings are infected with moulds. Moulds occur in the indoor environment e.g. when humid air condensates on cold outer walls or in connection with water damage which is insufficiently dried out. In our analyses we always try to determine moulds both to genus and species. During our surveys in August 2001 and February 2002 we found 50 different species of moulds in Danish houses. The species Penicillium chrysogenum was dominating in both spring and autumn. Aspergillus versicolor was also present in spring and autumn but in smaller numbers. Cladosporium herbarum was most common during autumn. Stachybotrys chartarum was rather rare, maybe because it is closely connected to gypsum boards. It is very important to identify the moulds to species which is shown by the following case study. In a house where the sewer had been punctured in connection with establishment of district heating, 150 cubic metres of water had poured into the crawl space. We were called in by the occupant because she felt ill and there was a strong mouldy smell. We immediately asked her to move, with the result that her health improved almost instantly. She was so sensible that even the delivery of mail in her mailbox made her ill. A blood-test showed that she was sensitised to Trichoderma viride and Penicillium chrysogenum. The latter was found in large amounts in her house. We know that it is now possible to repair the house so that non-sensitised persons will be able to live there, but not the former occupant who will react to even small traces of allergen which are still there. After the repair we have different methods of quality control. It is now evident that some remedies and methods will kill the spores others the mycelium and yet others both. Some methods have a lasting effect, others do not. Our methods of quality control are either contact-samples with Petri dishes where mould colonies are counted and identified to species or a test for ATP or the Mycometer-test where the enzyme β-N-acetylhexosaminidase specific to fungi is measured. The Petri dish method measures the number of living spores, while the two other methods measure the amount of mycelium. However it seems that ATP in the mycelium is broken down faster than the enzyme measured by the Mycometer-test. Therefore it becomes difficult to decide whether the mycelium is living, partly dead or completely dead, when the repair work is going to be approved.
J Bech-Andersen, S A Elborne
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
Seasonal effects of the field evaluation on wood preservatives against mold fungi
1996 - IRG/WP 96-20087
For the purpose of the amelioration of field test methods, commercial preservatives against mold fungi were tested under two different seasons, in winter and in summer. The specimens were bundled and set over the water bath and all these systems were covered with plastic film. At top of the system under film, black films for regeneration of sunlight were put in, and windows for changing air were reserved in summer. The visual evaluation of damage (rating 0-4) was done periodically. The results obtained as follows. 1.) The evaluation values after 2 months in winter were simmilar results as those after 3 weeks in summer. 2.) The fungicides, mixture of nitoril compound and organo nitrogen sulfuric compound, mixture of thiocyanate compound and organo nitrogen sulfuric compound, were obtained good results in field. Those percentage of the specimens rating under 1 were more than 50% and those mean rating were not more than 2. 3.) In the case of organo iodide compound, the results in winter were good but in summer were not so good.
K Suzuki, Y Sugai, K Ryugo, D Watanabe
Climate indices at work: Above ground decay L-joint tests (EN 330 and AWPA E9) at two sites 12000 km apart and with Scheffer climate indices of 60-65 and 300-330
1996 - IRG/WP 96-20095
Matched sets of Scots pine sapwood (Pinus sylvestris) L-joints were exposed above ground at two field sites for approximately five years. One site, at Garston, Watford, UK has a climate index between 60 and 65 while the other, close to Hilo, HI, USA has an index between 300 and 330. The joints were treated with a range of organic solvent treatments applied either by three minute dip immersion or by double vacuum. Untreated joints were installed at each site as control material. All samples were assessed at approximately annual intervals at both sites. After five years, decay at the Hilo site is well advanced with failure apparent in many joints, both untreated and treated. As would be expected given the climatic differences, decay at the Garston site has progressed more slowly than in Hilo. Differentiation in treatment performance was apparent after one year's exposure in Hilo with similar differentiation becoming apparent after five years' exposure in Garston. This acceleration correlates well with the difference in Climate Index for the two sites as calculated using the Scheffer method. Encouragingly, the performance ranking of the different treatments at the two sites was very similar. The results of this test suggest that the concept of using high decay hazard sites for field testing of treated wood products for use in above ground situations can provide meaningful results in a short period, and may offer a timely and realistic alternative to relative preservative testing to that achieved in laboratory test regimes. The results also show that above ground field testing at both of the sites included provide valuable information on preservative performance, and this information is likely to provide a greater degree of realism than is possible using pure culture laboratory test procedures.
A F Preston, K J Archer, D M Roberts, J K Carey, A F Bravery
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
List of wood-destroying fungi in Iran
1976 - IRG/WP 138
This list gives information on the wood-destroying fungi collected in the Iranian forests and from felled logs and boards in sawmills until now. They are mainly from the region of the Caspian Forests and from the climatically dry region between Teheran and Azarbaidjan, North Iran. It is understood, that this document may help to give more knowledge outside the country about the specific problems of Iran, or concerned with the regions of the Middle East with great varieties of climate. The collection, which is far from complete, includes 76 species of fungi belonging to 46 different genera. Several of the species have been published already nationally, some internationally. Some species have just been recognised recently in Iran and are mentioned for the first time. These species are marked with (+). All samples of fungi collected are conserved and kept in the laboratories of the Department of Wood Science at the Faculty of Natural Resources, Karadj. Their identification was undertaken by the author and with help of the Centre Technique du Bois, Services des Recherches et Essais (Lab Mycologie du Bois), Paris, and of the Royal Botanic Gardens, Kew.
Natural weathering of wood in a sunny climate effects on surface chemistry and paint adhesion
1997 - IRG/WP 97-20109
Radiata pine veneers and blocks were exposed to natural weathering under Australian summer conditions over a period of 30 days. Infrared spectroscopy revealed that there was perceptible surface delignification after 4 hours exposure, substantial surface delignification after 3 days exposure and almost complete surface delignification after 6 days. Viscometry determinations on holocellulose samples from weathered veneers and unweathered controls indicated significant depolymerisation of cellulose after short periods of weathering. A tape test was used to assess the adhesion of acrylic latex primers to weathered blocks. The adhesion of exterior acrylic primers decreased on weathered wood surfaces and was significantly lower on specimens that were weathered for 5 to 10 days. An oil-modified acrylic primer showed greater adhesion to weathered wood surfaces. Primer adhesion was lower on weathered radial surfaces than on similarly exposed tangential surfaces. The practical implications of these findings for the coating of exterior wood with acrylic latex primers and the development of photoprotective treatments for wood are discussed briefly.
P D Evans, P D Thay, K J Schmalzl
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