Your search resulted in 47 documents. Displaying 25 entries per page.
Differences in feeding activity among colonies of Formosan subterranean termite Coptotermes formosanus Shiraki
1983 - IRG/WP 1202
Feeding activities of 7 colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were examined. Wood-consumption rates among colonies differed significantly, ranging from 23.80-78.48 mg/g/day. This large intraspecific variation raised a question of whether differences in feeding activity reported for other termite species were due to interspecific differences. When rates were expressed as mg wood consumed by one g termite per day (mg/g/day), termites of larger body weight appeared to consume less wood. This negative correlation, however, was not significant when rates were expressed as mg wood consumed by an individual per day (mg/worker/day).
N-Y Su, J P La Fage
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
Successive collections of Basidiospores from wood decay fungi (in vitro) show variation in germination levels on common media
1978 - IRG/WP 191
In the course of various preliminary experiments in which spore germination levels of 6 decay fungi on malt and water agar were recorded as controls, it was noted that one could not reliably obtain an expected level of spore germination for any particular fungus. Inconsistent 'control' spore germination levels of a fungus greatly complicates large scale experiments in which comparisons of data based on germination levels are attempted upon replication of the study over time. This study was done to determine if, in fact, spores collected at different times from specific hymenial areas of wood decay fungi sporulating in vitro differed significantly in germination level on common media under standardized conditions.
E L Schmidt, D W French
An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong
Analysing the characteristic role of moisture content for drying and fluid flow in Sitka spruce. - Part 1: The drying process of sapwood and heartwood of two different thickness of Sitka spruce using a kiln. - Part 2: Effects of moisture content on longitudinal permeability of Sitka spruce in vertical variation of the tree
2000 - IRG/WP 00-40173
The characteristic role of the moisture content in Sitka spruce (Picea sitchensis (Bong.) Carr.) that grown in the United Kingdom was examined by this study on the basis of (1) the reduction of moisture content in two different thickness of sapwood and heartwood by kiln drying process, and (2) the effects of moisture content to the longitudinal void volume filled of tanalith-C by the full-cell process from base (1 m) to apex (3 m) of the tree in sapwood zone. Accordingly, conclusions on indication of the drying process of sapwood and heartwood, and vertical variation of longitudinal flow with effects of moisture were listed separately: (1) Comparison of Drying Characteristic of Sapwood and Heartwood: The two different thickness (300x30x30 mm3 and 300x20x20 mm3) of sapwood and heartwood of Sitka spruce was dried using the suggested drying schedule in kiln. The reduction of moisture was schematically diagrammed according to sapwood and heartwood stakes. The reduction of moisture followed the same downward trend that sapwood (S) loses more moisture than heartwood (H) although the small stakes of S and H lost moisture rapidly compared with the large ones. (2) Vertical Variation of Moisture Content and Longitudinal Permeability: The 90 kiln dried defect free sapwood stakes (150x25x25 mm3) of Sitka spruce was taken from base to apex of the trees at 1, 2 and 3 m above ground level. After having the determination of moisture content in each experimental stake, the treatment was carried out by the full-cell process with CCA preservative (Tanalith-C) using a model pressure treatment plant. Significant differences observed among the tree heights from 1 to 3 m showing that slightly increases of moisture content from base to apex and conversely decreases of longitudinal void volume filled by preservative fluid.
The effects of density on vertical variation of permeability of Sitka spruce within tree
2000 - IRG/WP 00-40156
Tree improvement of Sitka spruce is a combination of silviculture and tree breeding aimed at producing higher quality products including increased growth rate and timber yield, and wood density. It is useful to know annual ring structure and density distribution when studying the quality of wood, grading it, or determining how the wood structure affects residual flow in softwoods. Since density is a factor under genetic control, the study in this article details the effects of density on longitudinal and radial permeability of Sitka spruce from base to apex. Comparison of overall means of both longitudinal and radial void volume filled (%) suggest that longitudinal permeabilities were almost the mirror image of those for the radial permeability along the tree trunk.
The variation in electrical resistance in the CCA-treated wood during the fixation
1989 - IRG/WP 3554
The curve commonly used in Scandinavia for describing the fixation period at different temperatures for CCA-impregnated wood is based on investigation by Dahlgren on the pH-variations in a mixture of sawdust and preservative solution. As far as we know there is no such investigation on solid wood. We have therefore measured the electrical resistance in CCA-treated solid wood to see if this will differ according to the different ion consentrations that are in the wood during the fixation process. Our investigation shows that the electrical resistance in the CCA-treated wood varies. At first the resistance will increase, then it will decrease and at last stabilize at a higher ohm-value than in the start. This variation may describe the fixation in the wood and perhaps be used to measure the fixation time at different temperatures for solid, impregnated wood.
F G Evans, B Nossen
Variation in Canadian bluestain fungi: Tolerance to DDAC and DOT
1999 - IRG/WP 99-10303
Bluestain in Canadian wood products results in significant and unpredictable losses each year. In order to develop rational methods to eliminate or reduce the sapstain problem, a more complete knowledge of the causal organisms must be gained. This includes a knowledge of the variability in tolerance of different fungal species and strains to commercially used chemicals. In British Columbia, the majority of anti-sapstain chemicals are based upon the quaternary ammonium compound DDAC, either as the sole active ingredient or in formulation with co-biocides such as disodium octaborate tetrahydrate (DOT). Ten strains each of the three most prominent blustain fungi found in Canada (Ophiostoma piceae, Ophiostoma piliferum, and Graphium (species C)) were evaluated for their tolerance to DDAC and DOT. The main findings showed there was little or no variation in the tolerance to the chemicals within the strains of each species tested. In the screening tests it was found that DDAC was less effective in inhibiting fungal growth than DOT. However, further examination revealed that the ineffectiveness of DDAC was due to interactions with the media components - a reminder that care must be taken when evaluating results especially with surfactants such as DDAC. Additional work with other sapstain control chemicals is underway.
J Dubois, A Byrne, J E Clark, A Uzunovic
Decay resistance of Scots pine (Pinus sylvestris) heartwood against brown rot
2002 - IRG/WP 02-10433
Natural decay resistance of wood is mainly restricted in the heartwood and based on wood microstructure and chemical composition. The genetic variation in the durability of Scots pine (Pinus sylvestris L.) wood against decay and the relationship between resistance and chemical composition was studied. The laboratory tests of 6 and 8 weeks were carried out with a brown rot fungus Coniophora puteana (Schum. ex Fr) Karst (strain Bam EBW 15). The increment core samples of sapwood and juvenile heartwood, obtained from about 30-year-old half-sib progenies, were decayed using a modification of the standardised EN 113 method. The average density of the sapwood was 391 mg/cm3 (one stand) and that of heartwood samples 337 and 376 mg/cm3 (two stands). The average mass loss of the sapwood samples was 114 mg/cm3 (6 weeks, stand 1) and that of the heartwood samples 80 mg/cm3 (6 weeks, stand 1) and 123 mg/cm3 (8 weeks, stand 2). The variation among heartwood samples was high. The additive genetic component was small in stand 1 but quite large in stand 2, which resulted in a low narrow sense heritability h2 in stand 1 (0.07) but high in stand 2 (0.37). New samples were taken from the most resistant and susceptible trees for chemical analyses. The concentration of resin acids was higher in the group of decay resistant trees than in the group of decay susceptible trees. About 90 % of the resin acids in the heartwood were of the abietane type, abietic acid being the most abundant.
H Viitanen, A M Harju, P Kainulainen, M Venäläinen
A method to evaluate the effeetiveness of bait application using a transferred nest of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)
1999 - IRG/WP 99-20161
Although a survey of monitoring stations can tell us the decline of termite activity after application of baits, it seems questionable to conclude an eradication of a Whole colony of subterranean termites if the termites move out their foraging territory. Only reliable method to ensure the success of bait application is to determine the absence of living termites in their nest in accordance with a survey of monitoring stations. A nest of Coptotermes formosanus was first collected from the field and buried back into the soil with some wooden blocks in a test site. Monitoring stations were installed around the nest to examine termite activity. After termites settled down well, mark-release-recapture was applied to estimate foraging population and then bait application was initiated. When foraging activity ceased, the nest was dug out to find any live termites present. This technique allowed us to draw out a conclusion that baiting eliminated a whole colony of C. formosanus.
K Tsunoda, T Yoshimura, H Matsuoka, Y Hikawa
Physical properties variation of sound and top dying affected sundriwood (Heritiera fomes) in mangrove forest of Bangladesh
2004 - IRG/WP 04-10504
Top dying of sundri (Heritiera fomes Buch.-Ham.) in the Sundarbans is considered to be the most severe of all the diseases of tree crops in Bangladesh. The wood samples from sound, moderately affected and severely affected sundri trees from three different tree heights for every individual test were collected and their respective physical properties were examined to make a comparison. It was found that density decreased with the increase of disease severity and was found 5% for both the cases. The volumetric shrinkages also increased due to top dying and were found 6.42% and 3.34% higher for moderately affected and severely affected trees respectively. Similarly the initial moisture contents also decreased due to top dying and were found 5.34% and 16.19% lower for moderately affected and severely affected trees respectively.
S C Ghosh, A K M A Bosunia, M A Islam, A K Lahiry
Sampling variation in a copper chrome arsenic treated power transmission pole
1990 - IRG/WP 2351
The Queensland Forest Service routinely samples poles treated at all treatment plants throughout the State. Each treatment plant is issued with a Certificate of Registration and the accompanying documents list the different levels of preservative retention required for performance in various service conditions. The posted levels represent the.minimum permissible, and it is to these concentrations of preservative that a piece of treated timber is tested. All samples taken must pass the required level of treatment. Because minimum levels are used, it is important to ensure that any samples taken are representative of the whole piece. A plug sample taken from a pole is 19 mm in diameter by the depth of the sapwood long. The 'analytical zone' is the inner 1/3 of the sapwood band closest to the truewood and the size of the 'analytical zone' varies with the thickness of sapwood. Analyses were carried out on a number of plug samples from a preservative treated power pole, to examine the variation in preservative retention that can occur when samples are taken from different locations along the pole.
Estimation of the population of a sound colony of Coptotermes lacteus (Froggatt)
1988 - IRG/WP 1353
Selecting an area with a high termite hazard is deemed essential in locating field sites in order to screen potential termiticides and wood preservatives. Yet, quantifying termite populations in such sites remains imprecise. There are major problems associated with estimating populations of termites in mound colonies (either free-standing or in trees), and these are briefly discussed. In this paper we estimate the population of a mound colony of Coptotermes lacteus as 3.06 x 105. The estimate relates to foragers collected at baits that had been inserted into the mound. The technique adopted, "removal sampling", did not destroy the integrity of the mound nor incur unnecessary expense.
D M Ewart, J R J French
Colony elimination of Reticulitermes speratus (Kolbe) (Isoptera:Rhinotermitidae) by bait system
1997 - IRG/WP 97-10189
Following a two-year estimation of the foraging populations and territory of Reticulitermes speratus (Kolbe) by triple mark recapture program at Uji campus of Kyoto University, bait stations (commercialized products containing hexaflumuron) were set up in the foraging territory in October 1995 to eliminate the colony. Inspections demonstrated that the number of test stakes with foraging termites decreased after May 1996. No attack was finally observed in July 1996. As a later inspection in October 1996 reconfirmed no termite hits on any wooden stake in the foraging territory, the colony was considered to be eliminated by baits.
K Tsunoda, H Matsuoka, T Yoshimura, K Yamauchi
Variation in infection rates of blue-stain, mould and white rot tropical fungi on mixed light Malaysian woods
2000 - IRG/WP 00-10334
The modified 3-week FRIM laboratory method for screening of anti-sapstain formulations against three representative tropical fungi causing blue-stain (Botryodiplodia theobromae), mould (Paecilomyces variotii) and white rot (Schizophyllum commune) infection of sapwood species was used to examine the relative resistance of the sapwood of eight mixed light Malaysian woods, Scots pine (Pinus sylvestris), medium density fibreboard produced from Rubberwood (Hevea brasiliensis) and the heartwood of Sentang (Azadirachta excelsa), to infection by these organisms. After 21 days it was found that Ramin (Gonystylus spp.), Rubberwood, Mersawa (Anisoptera sp.), Ludai (Sapium spp.), Yellow meranti (Shorea spp.), Scots pine and Jelutong (Dyera costulata) were highly susceptible to the pooled combinations of blue-stain, mould or white rot infection often sustaining >50% overall mean fungal coverage or when at least one of the infection types has reached maximum mean coverage (75.5%) of the wood samples. However, the Rubberwood-based fibreboard, and particularly Sentang, and the softwood Agathis spp. from Kelantan (trade name: Damar minyak) and Sarawak (trade name: Bindang), were relatively moderately susceptible to infection, sustaining between 9 and 47% overall mean fungal coverage after 21 days, or even considerably less susceptible (5 - 20% overall coverage) after 14 days. There was absence of both blue-stain and white rot fungal growth on all samples dipped in a low (0.03%/0.03%) fungicide concentration of a MBT/TCMTB anti-sapstain formulation. Such laboratory test results could have significant implications to field or industrial sapstain control of sapwood timbers concerning the lag time between tree felling and anti-sapstain treatment and seasoning.
A H H Wong, S Ahmad
Investigation on different variation factors in the results of mycological test and means to reduce and avoid them
1986 - IRG/WP 2264
In order to clarify the causes of the dispersion observed in the results obtained with mycological tests made in accordance with standard EN-113, different factors assumed to be sources of the variations were studied. These included the moisture content of the test samples during the test, the influence of certain technological properties of the wood, the virulence of the fungus strains, the method by which the test pieces were treated and the effect of the solvent, and behaviour of the wood fungus in contact with the wood preservative. It turns out that certain factors which were supposed to be important are actually secondary (humidity). On the other hand, the virulence of the strains is a major problem and requires a serious examination. Treatment by dipping with a ready-to-use product might avoid errors due to obligatory dilutions. In the end, wood species other than beech and Scots pine be used. However, one must not lose sight of the fact that there is a risk that the toxic values may not always be identical.
Longterm monitoring of termite activity on multiple feeding sites: a laboratory method intended for the determination of attractant/repellent properties of wood preservatives and baits
2001 - IRG/WP 01-20225
A method is introduced allowing the continuous monitoring of the activity of a small laboratory termite- colony at 8 different feeding sites simultaneously. The test assembly consists of a small central polycarbonate-tube containing a colonie of Reticulitermes santonensis (de Feytaud) beeing connected with 8 external feeding sites by small glass-capillaries. The termites passing through the glass capillaries to and from the feeding sites are interrupting an infrared light-barrier. Each signal from the light-barriers is conditioned and fed to a PC-based signal-recognition-, monitoring- and storage-system. First results show that a colony of 500 individuals of Reticulitermes santonensis (de Feytaud) will need approx. 2 to 3 weeks for establishing a new, full functional hierarchy. A well established Reticulitermes- colony will show 80 to 100 passings per minute to and from the eight feeding sites. The activity of Reticulitermes santonensis (de Feytaud) shows no circadian activity rhythmic.
M Pallaske, E Graf, H Takiuchi
Decay resistance of Siberian larch wood against brown rot fungi - Part 2. The effect of genetic variation
1998 - IRG/WP 98-10287
Wood natural decay resistance is mainly restricted in the heartwood part of tree and based on wood microstructure and chemical composition. However, the variation of decay resistant in different wood species is vide and the effect of genotype on decay resistance of Siberian larch wood grown in Finland is not known. The aim of this work was to find out the variation on decay resistance of Siberian larch from different genotypes using a preliminary screening test based on a malt agar block decay test (a modified EN 113 test). The increment core samples were collected in October 1997 from 53 different clones and the decay tests started in January 1998 and were finished at the end of March 1998. In future, these results can be used to find most decay resistant material for forest tree breeding.
H Viitanen, L Paajanen, T Nikkanen, P Velling
Variation in natural durability of British grown Douglas fir ((Pseudotsuga menziesii (Mirb.) Franco). Part I. Effect of density and growth rate
2002 - IRG/WP 02-10445
Seed origin trials of Douglas fir (Pseudotsuga menziesii) in Britain have provided important information on growth differences between origins (Lines, 1987), but the variation in wood properties between origins has not been reported. The present paper describes a study of the variation in natural durability against two brown rot fungi (Coniophora puteana and Postia (Poria) placenta) and in a fungal cellar test between four seed origins of Douglas fir. In addition to natural durability, tree diameter, heart-, sap- and total cross-sectional areas, density, bending properties, extractive content and composition were determined to examine their effect on natural durability. The effects of extractive content and composition on durability are discussed in a second paper (Part II: Effect of extractive content and composition). The proportion of the total variation in natural durability explained by differences between seed origins and differences between trees within origins were estimated to indicate the potential of tree breeding programmes for modifying this wood property. (Poria) placenta) and in a fungal cellar test between four seed origins of Douglas fir. In addition to natural durability, tree diameter, heart-, sap- and total cross-sectional areas, density, bending properties, extractive content and composition were determined to examine their effect on natural durability. The effects of extractive content and composition on durability are discussed in a second paper (Part II: Effect of extractive content and composition).
S Akhter, M D C Hale
Variation of natural durability of sugi (Cryptomeria japonica) wood in 15 clones examined by decay test (Preliminary report)
2004 - IRG/WP 04-10526
Natural durability of wood in 27 trees from 15 clones of sugi (Cryptomeria japonica)　 was investigated by an accelerated decay test. Thirty years old trees were collected from a clonal trial in Ibaraki prefecture, Japan. Natural durability is usually evaluated in heartwood. Mass losses of heartwood caused by a brown rot decay fungus, Fomitopsis palustris and a white rot decay fungus, Pycnoporus coccineus were ranged from 0% to 29% and 0% to 14% respectively. The coefficients of their variation among 27 sample trees were 80 % and 38% in mass loss of heartwood by these fungi. Heartwood from one clone was subjected to be low level of mass loss by both fungi. Trees from the clone could be classified into durable. It might be possible to select sugi clones having durable heartwood.
K Yamamoto, A Tamura, R Nakada
Effect of humidity fluctuations on mould growth on pine wood
1989 - IRG/WP 1412
Most studies on mould development on wood material have been made at constant moisture conditions during the experimental period. As a consequence of such studies, a maximum permittable humidity level to avoid mould problems in wood constructions has been recommended. In the practical situation, the constructions are seldom subject to constant humidity or temperature. In the present paper, we report on studies on mould growth on wood during controlled fluctuations of the humidity conditions. The results indicate less adaptability to moisture fluctuations at higher temperatures.
Decay resistance of Siberian larch wood against brown rot fungus. - Part 3. The variation between plus trees and their grafted clones
2000 - IRG/WP 00-10350
The aim of the study was to estimate the variation in the decay resistance of Siberian larch (Larix sibirica Ledeb.) wood using mature plus trees and their grafted clones. Samples were collected with an increment core borer from 11 original plus trees and their 25-year-old grafted seed orchard clones. A typical brown rot fungus, Coniophora puteana (Schum. ex Fr.) Karst. (BAM Ebw. 15), was used as the decaying organism. The mass loss after 6 weeks' incubation was observed. The results showed that the fast growing wood of the grafts was more susceptible to decay than the wood of the original plus tree. The results showed also radial variation within the mature plus tree logs: the inner part of the heartwood was more susceptible to decay than the outer part of the heartwood. The main advantages of decaying the increment core samples were the possibilities to study standing trees, and to screen large numbers of samples at reasonable costs.
H Viitanen, L Paajanen, M Venäläinen, A Harju, P Velling
Variation in natural durability of British grown Douglas fir ((Pseudotsuga menziesii (Mirb.) Franco). Part II. Effect of extractive contents and taxifolin
2002 - IRG/WP 02-10446
The previous paper (Part I: Effect of density and growth rate) described the variation in natural durability of 4 Douglas fir (DF) seed origins (Darrington, J. Landing, Naselle and Hawkinsville) in a pure culture decay test and fungal cellar test. The pure culture tests were performed against two brown rot fungi (Coniophora puteana and Postia placenta). In the fungal cellar test soft rot was the predominant decay type because of the high moisture content. The paper showed that significant variation in natural durability occurred between the seed origins and between trees within the seed origins. Furthermore density partly explained the variation in the natural durability of 3, of the 4 seed origins. Extractives are often considered to be the major reason for heartwood durability. This paper has determined the variation in extractive contents between different seed origins and has examined the effect of extractive contents and taxifolin, the main component of acetone extracts on the decay resistance of 26 year old DF trees from different seed origins.
S Akhter, M D C Hale
Effect of substrate type and moisture requirements in relation to colony initiation in two carpenter ant species
1999 - IRG/WP 99-10320
Conditions necessary for optimal colony initiation or the rate of initial colony expansion by early brood in the carpenter ant species Camponotus modoc and C. vicinus on various substrates conditioned to different moisture contents were studied. Camponotus modoc and Camponotus vicinus queens were placed in Douglas-fir, western red cedar and Styrofoam® blocks conditioned in sealed chambers at 70% or 100% relative humidity. Chambers were periodically monitored for changes in substrate weight, numbers of eggs, larvae, pupae, and worker ants produced. Brood counts produced after thirteen weeks were used to assess the effects of substrate and moisture content on colony initiation. Queens of C. vicinus in Douglas-fir and Styrofoam® produced worker numbers that did not differ significantly with moisture content. However, the number of colonies initiated for C. modoc did significantly differ with moisture content. The results indicate that colony initiation in C. vicinus is less sensitive to moisture content then C. modoc for Douglas-fir and Styrofoam®. No differences were found between moisture contents for ant queens in western red cedar, due to a lack of colony initiation. These results suggest that cedar was detrimental to the development of early brood in both ant species.
M E Mankowski, J J Morrell
Is termite body size correlated with colony vigor?
1995 - IRG/WP 95-10130
Folk wisdom among termite researchers holds that the average body size (mass) of workers in a subterranean termite colony (Rhinotermitidae) is associated with the age and/or vigor of the colony. In particular, extremely large individuals are frequently thought to indicate a very old, or senescent, termite colony. However, there are very little data to support this assumption. It is also difficult to understand why subterranean termite colonies of advanced age, with a continuing food supply and supplementary reproductives presumably active in egg production, should be prone to senescence. We present data from 16 years of observations on a Coptotermes formosanus Shiraki field colony demonstrating a negative proportional relationship between average individual worker mass and estimated size of the colony foraging population. These results do not explain the phenomenon of senescence, but do suggest that decline in colony population size may be predicted from a measured increase in the average individual mass of workers sampled over a given period of time.
J K Grace, R T Yamamoto, M Tamashiro