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PubMed1993

Production of tremorgenic mycotoxins by isolates of Aspergillus fumigatus from sawmills in Sweden.

One hundred and six strains of A. fumigatus were isolated from 21 sawmills in Sweden, and 73 of these strains were examined for production of fumitremorgen B and verruculogen (tremorgenic mycotoxins) on YES-medium using thin layer chromatography (TLC). Twenty-three strains (32%) were tremorgen producers and 50 strains (68%) were non-producers. Tremorgenic mycotoxins were detected in conidia of seven A. fumigatus strains. The amount of toxin varied between 0.6-8.0 microgram/10(8) conidia (mean value 2.3 micrograms/10(8) conidia, equivalent with 0.18%). No production of the mycotoxin gliotoxin was detected in 6 strains of A. fumigatus. No tremorgens were detected during mould growth on wood substrates, in spite of the use of different wood species (Scots pine, Pinus sylvestris: Norway spruce, Picea abies and birch, Betula spp.), dried versus non-dried wood, bark (pine), leached wood, and wood after various sterilization methods.

Air Pollutants↗
PubMed1993

Measurements of year-long exposure to tree nursery workers using multiple pesticides.

A year-long nurseryworker pesticide exposure study was designed to measure and evaluate the exposure occurring to workers who had the potential for simultaneous exposure to multiple pesticides. This four-State study was conducted in five nurseries (four USDA Forest Service and one State) involved in conifer seedling production. Primary comparisons were made among nursery workers in the Pacific northwest and south central United States. Worker exposure was assessed by using patches attached to clothing, handrinse samples and urine excreted from potentially exposed workers. In addition, dislodgeable residue in rinsate from a water wash of pesticide-treated seedlings was also evaluated. Four different groups of field workers, designated as applicators, weeders, scouts and packers, were included. The pesticide absorbed dose, assessed by urine analysis of pesticide metabolites and the deposition of pesticide on patches attached to the clothing of field workers, was monitored as they performed their duties under normal conditions (e.g., typical clothing, pesticide application). Monitoring was performed for the 14 different pesticides which were used in these nurseries. Seven pesticides were studied in more detail using biological monitoring. For these compounds, metabolites known to be excreted in the urine of exposed humans or other mammals were used to estimate the dose of pesticide absorbed by the exposed workers. The highest percentage of positive samples came from dislodgeable residue samples (8.3%) followed by patch samples (3.2%), handrinse (2.9%), and urine samples (1.3%). To summarize the conclusions from the urinary excretion data, 12 of the 73 nursery workers in the study received a low absorbed dose of pesticide. Biological monitoring revealed that three pesticides (benomyl, bifenox and carbaryl) were found in the urine of some of the workers. Of the 3,134 urine samples analyzed there were 42 positive; 11 urine samples were positive for benomyl, while bifenox was responsible for 13 positives and carbaryl accounted for the remaining 18. The 12-week continuous monitoring of urine showed that metabolites of these materials were rapidly excreted; thus, no build-up in the body is anticipated. Margins of Safety (MOS) calculations were made to provide an assessment of the significance of the exposure. Based on the low frequency of positive urine samples in the study, the low levels of metabolites when they were found, their apparent rapid excretion rate and the No Observed Effect Level (NOEL) data, furnished from other sources, nursery worker exposure to pesticides in these conifer nurseries is below health threatening levels.

Adult↗
PubMed2002

Distribution, population density, and status of sympatric cercopithecids in the Campo-Ma'an area, Southwestern Cameroon.

A study on species composition, distribution, and population density of cercopithecids in the Campo-Ma'an area, Southwestern Cameroon, was undertaken from December 1997 until August 2000. A total of 665.5 km of line transects was used for the census. Thirteen diurnal primate species including five endangered species (Gorilla g. gorilla, Pan troglodytes, Mandrillus sphinx, Colobus satanas, Cercocebus torquatus) were recorded in the Campo Forest, the greatest part of which is a logging concession. Cercopithecus nictitans (1.43 groups/km2), C. cephus (1.13 groups/km2), C. pogonias (0.81 groups/km2), and C. torquatus (0.51 groups/km2) occurred at medium frequencies compared to figures from other Central African study sites. Mandrill densities estimated (0.27 groups/km2) show that the area is very important for the conservation of this rare species. Guenon densities found inside areas with a high level of human activities did not differ significantly from densities estimated in areas with a lower level of human activities. C. torquatus densities were significantly higher in the areas with a low level of human disturbance and encounter rates with Lophocebus albigena also indicate a preference of less disturbed areas. Mangabeys are thus likely to be adversely affected by human activities in the area. In the Ma'an Forest, which has not been logged yet, ten species were confirmed. The population densities of two guenons (C. nictitans and C. cephus) were estimated to be twice as high in the unlogged forest area as compared to the logged forest of Campo. Other species are rarer in the Ma'an Forest than in the Campo Forest. Although mangabeys are adversely affected by human activities, the results still indicate that selective logging may be compatible with the conservation of cercopithecids, if a reduced damage logging concept and antipoaching measures are implemented. Increased hunting activities following logging operations will definitely have a negative longterm impact on primate populations in the Campo-Ma'an area if no further, more effective conservation measures will regulate wildlife use in future.

Animals↗
PubMed2004

Addressing the concerns of rural communities about access to plants and knowledge in a sui generis legislation in Cameroon.

This article assesses the traditional systems of accessing and using plant genetic resources as well as the benefit sharing and systems of sanctioning infringement in the context of biodiversity related activities in specific areas in the Northwest province of Cameroon. The article also addresses the type research and development activities using plant genetic resources and associated traditional knowledge in the context of Cameroon, the current laws regulating such activities and the extent to which these activities and laws affect and/or protect the customary biodiversity rights of rural communities. The article uses these assessments to suggest the context under which a sui generis legislation for the protection of the biodiversity rights of rural communities can be established in Cameroon.

Biodiversity↗
PubMed2002

Free-air fumigation of mature trees. A novel system for controlled ozone enrichment in grown-up beech and spruce canopies.

A novel system for continuous and controlled free-air fumigation of mature tree canopies with ozone is described. Ozone generated from oxygen is diluted with air in a pressurized tank and conducted into the canopies by a system of 100 PTFE tubes hanging down from a grid fixed above the crowns. With 45 calibrated outlets per tube providing a constant flow of 0.3 l/min each, a total volume of about 10*10*15 m3 comprising 5 beech and 5 spruce canopies is fumigated. The spatial ozone distribution in the fumigated volume as well as surrounding reference tree canopies is controlled by continuous measuring instruments installed at 4 levels and a dense array of passive samplers. The system will later be used for CO2 fumigation as well. Results of the first year of continuous operation, with 2 * ambient ozone levels having been achieved, are reported.

Forestry↗
PubMed1997

Forest tree biotechnology.

The forest products industry has traditionally viewed trees as merely a raw, and more or less immutable, natural resource. However, unlike such inanimate resources as metallic ores, trees have the potential to be modified genetically, essentially transmuting lead into gold. Increasingly, modern alchemists are applying the tools of biotechnology in efforts to reduce the biological constraints on forest productivity. Several new methodologies being used to address problems in forest biology are described with respect to their potential impact on forest tree improvement. In addition to addressing problems inherent to the current use of trees for production of pulp and paper or solid wood products, genetic manipulation of trees brings with it the potential to create new industries based on the novel characteristics of transgenic trees, e.g. trees containing transgenes to detoxify specific pollutants could be used in the remediation of sites contaminated with hazardous wastes. Efforts to modify trees through biotechnology are in their infancy, and this review seeks to outline the underpinnings of what will undoubtedly be an area of increased emphasis in the next millennium.

Biotechnology↗
PubMed2002

Genetic diversity impacts of forest fires, forest harvesting, and alternative reforestation practices in black spruce (Picea mariana).

Benchmarks were established for genetic diversity inherent in natural mature populations, and genetic diversity impacts of forest fires, clearcut harvesting and alternative natural and artificial silvicultural regeneration practices were determined in black spruce (Picea mariana). Allozymes of 32 loci were used to determine and compare genetic diversity and genetic relationships of adjacent or nearby four stand types: post-fire natural mature (FNM), post-fire natural young (FNR), post-harvest natural young (HNR) and post-harvest plantation (PLT), of black spruce at each of the four study sites located in two ecoregions in Manitoba: Ecoregion 90-Lac Seul Upland (Eastern) and Ecoregion 158 - Mid-Boreal Lowland (Northern). Both allelic- and genotypic-based genetic diversity parameters, as well as latent genetic potential, were determined. Black spruce populations showed typical moderate to high levels of allozyme genetic diversity. The mean genetic diversity parameters over the 16 black spruce populations sampled were as follows: percent loci polymorphic - 67%, mean number of alleles per locus - 2.52, effective number of alleles per locus - 1.70, observed heterozygosity - 0.222, expected heterozygosity - 0.308, mean number of observed genotypes per locus - 3.65, mean number of expected genotypes per locus - 5.03, genotype additivity (observed) - 116.8, genotype additivity (expected) - 161, genotype multiplicity (observed) - 6.16 x 10(15), genotype multiplicity (expected) - 2.06 x 10(19) and latent genetic potential - 26.12. The four stand types (FNM, FNR, HNR and PLT) had comparable and statistically similar genetic diversity levels at each of the four study sites as well as overall. No significant differences in black spruce genetic diversity levels were observed between the two ecoregions in Manitoba, as well as between the post-fire and post-harvest regenerated stands. No particular order of genetic relatedness among the four stand types was observed. Black spruce populations showed some sort of site-related differentiation in their genetic constitution. Allelic heterogeneity and genetic distances among populations within stand types and among four stand types suggest that the genetic diversity was maintained at the landscape level in black spruce. The results of our study demonstrate that forest fires and currently used clearcut harvesting, and alternative natural and artificial silvicultural regeneration practices, do not adversely affect genetic diversity in black spruce, and that the genetic diversity effects of clearcut harvesting are not significantly different from those due to forest fires in black spruce.

Alleles↗
PubMed2003

Genetic evaluation of alternative silvicultural systems in coastal montane forests: western hemlock and amabilis fir.

Genetic diversity and mating system were quantified for shelterwood, patch cut and green tree-retention silvicultural systems, and compared to adjacent old-growth. This is a component of a larger study conducted in montane old-growth forests of coastal British Columbia to evaluate the feasibility and ecological consequences of alternative silvicultural systems. The experiment includes replicated treatments representing a range of overstory removal adjacent to old-growth and clearcut areas. Based on 22 electrophoretically assayed loci, the effects of silvicultural systems on genetic parameters of amabilis fir (Abies amabilis and western hemlock (Tsuga heterophylla were assessed by comparing an average number of alleles per locus, the percent polymorphic loci, and observed and expected heterozygosity between parental populations and naturally regenerated progeny as well as among treatments. Genetic variation in natural regeneration was greater than in parental populations, especially for low-frequency alleles. Silvicultural treatments caused no significant differences in amabilis fir genetic-diversity parameters, while the shelterwood system resulted in lower observed and expected heterozygosity in western hemlock. Nei's genetic distance revealed that all parental populations were extremely similar. The two species had contrasting mating system dynamics with amabilis fir producing higher levels of correlated paternity and inbreeding with wider variation among individual tree outcrossing-rate estimates. Western hemlock had significant levels of correlated paternity only for the green tree and shelterwood treatments demonstrating family structuring inversely related to stand density. Inbreeding in western hemlock was significant but lower than that observed for amabilis fir with a J-shaped distribution for individual tree multilocus outcrossing-rate estimates. The pollination and dispersal mechanisms of the two species represent the most-likely factors causing these differences. Artificial regeneration may be utilized to augment the genetic resources of natural ingress.

Abies↗
PubMed2003

Positive assortative mating with selection restrictions on group coancestry enhances gain while conserving genetic diversity in long-term forest tree breeding.

Selection and mating principles in a closed breeding population (BP) were studied by computer simulation. The BP was advanced, either by random assortment of mates (RAM), or by positive assortative mating (PAM). Selection was done with high precision using clonal testing. Selection considered both genetic gain and gene diversity by "group-merit selection", i.e. selection for breeding value weighted by group coancestry of the selected individuals. A range of weights on group coancestry was applied during selection to vary parent contributions and thereby adjust the balance between gain and diversity. This resulted in a series of scenarios with low to high effective population sizes measured by status effective number. Production populations (PP) were selected only for gain, as a subset of the BP. PAM improved gain in the PP substantially, by increasing the additive variance (i.e. the gain potential) of the BP. This effect was more pronounced under restricted selection when parent contributions to the next generation were more balanced with within-family selection as the extreme, i.e. when a higher status effective number was maintained in the BP. In that case, the additional gain over the BP mean for the clone PP and seed PPs was 32 and 84% higher, respectively, for PAM than for RAM in generation 5. PAM did not reduce gene diversity of the BP but increased inbreeding, and in that way caused a departure from Hardy-Weinberg equilibrium. The effect of inbreeding was eliminated by recombination during the production of seed orchard progeny. Also, for a given level of inbreeding in the seed orchard progeny or in a mixture of genotypes selected for clonal deployment, gain was higher for PAM than for RAM. After including inbreeding depression in the simulation, inbreeding was counteracted by selection, and the enhancement of PAM on production population gain was slightly reduced. In the presence of inbreeding depression the greatest PP gain was achieved at still higher levels of status effective number, i.e. when more gene diversity was conserved in the BP. Thus, the combination of precise selection and PAM resulted in close to maximal short-term PP gain, while conserving maximal gene diversity in the BP.

Computer Simulation↗
PubMed2003

Effects of inbreeding on coastal Douglas fir growth and yield in operational plantations: a model-based approach.

In advanced generation seed orchards, tradeoffs exist between genetic gain obtained by selecting the best related individuals for seed orchard populations, and potential losses due to subsequent inbreeding between these individuals. Although inbreeding depression for growth rate is strong in most forest tree species at the individual tree level, the effect of a small proportion of inbreds in seed lots on final stand yield may be less important. The effects of inbreeding on wood production of mature stands cannot be assessed empirically in the short term, thus such effects were simulated for coastal Douglas fir [ Pseudotsuga menziesii var. menziesii (Mirb.) Franco] using an individual-tree growth and yield model TASS (Tree and Stand Simulator). The simulations were based on seed set, nursery culling rates, and 10-year-old field test performance for trees resulting from crosses between unrelated individuals and for inbred trees produced through mating between half-sibs, full-sibs, parents and offspring and self-pollination. Results indicate that inclusion of a small proportion of related clones in seed orchards will have relatively low impacts on stand yields due to low probability of related individuals mating, lower probability of producing acceptable seedlings from related matings than from unrelated matings, and a greater probability of competition-induced mortality for slower growing inbred individuals than for outcrossed trees. Thus, competition reduces the losses expected due to inbreeding depression at harvest, particularly on better sites with higher planting densities and longer rotations. Slightly higher breeding values for related clones than unrelated clones would offset or exceed the effects of inbreeding resulting from related matings. Concerns regarding the maintenance of genetic diversity are more likely to limit inclusion of related clones in orchards than inbreeding depression for final stand yield.

Analysis of Variance↗
PubMed2003

Identification of AFLP markers linked to a resistance gene against pine needle gall midge in Japanese black pine.

Bulked segregant and AFLP analyses of two mapping populations (R17 x S6 and R17 x S1) were used to identify markers linked to Rpgm, the only known gene responsible for resistance to pine needle gall midge in Pinus thunbergii Parl. Rpgm was found to be bracketed by ACCC/CCTTT(190) on one side at a distance of 6.6 cM and ACGT/CCCGC(250) at 15.3 cM on the other side. The segregation of these markers was analyzed in two other families in order to determine their phase and transferability. One of the two additional resistant parents carried ACCC/CCTTT(190) in the homozygous state while the marker was in coupling (plus marker allele linked with an R allele) in a resistant parent, R17. The marker ACGT/CCCGC(250) was in a repulsion phase in R17 and was not detected in the other two resistant pine trees. Out of four AFLP markers identified, only ACGT/CCAAT(290) was transferable in all resistant trees tested, although its phase was opposite for different trees. These results indicate that in applying those markers to select resistant trees, the phase state of the markers in each resistant tree with respect to Rpgm needs to be considered.

Animals↗
PubMed2004

Retrospective selection of elite parent trees using paternity testing with microsatellite markers: an alternative short term breeding tactic for Eucalyptus.

The conventional way to drive modifications in old forest tree seed orchards is to establish progeny trials involving each parent tree and then evaluate its contribution to the performance of the progeny by estimating its general and specific combining ability (GCA and SCA). In this work, we successfully applied an alternative parent selection tactic based on paternity testing of superior offspring derived from a hybrid seed orchard established with a single Eucalyptus grandis seed parents and six E. urophylla pollen parents. A battery of 14 microsatellite markers was used to carry out parentage tests of 256 progeny individuals including two independent samples of selected trees and one control unselected sample, all derived from 6-year-old forest stands in eastern Brazil. Paternity determination was carried out for all progeny individuals by a sequential paternity exclusion procedure. Exclusion was declared only when the obligatory paternal allele in the progeny tree was not present in the alleged parent tree for at least four independent markers to avoid false exclusions due to mutation or null alleles. After maternity checks to identify seed mixtures and selfed individuals, the paternity tests revealed that approximately 29% of the offspring was sired by pollen parents outside the orchard. No selfed progeny were found in the selected samples. Three pollen parents were found to have sired essentially all of the offspring in the samples of selected and non-selected progeny individuals. One of these three parents sired significantly more selected progeny than unselected ones ( P< or =0.0002 in a Fisher exact test). Based on these results, low-reproductive-successful parents were culled from the orchard, and management procedures were adopted to minimize external pollen contamination. A significant difference ( P<0.01) in mean annual increment was observed between forest stands produced with seed from the orchard before and after selection of parents and revitalization of the orchard. An average realized gain of 24.3% in volume growth was obtained from the selection of parents as measured in forest stands at age 2-4 years. The marker-assisted tree-breeding tactic presented herein efficiently identified top parents in a seed orchard and resulted in an improved seed variety. It should be applicable for rapidly improving the output quality of seed orchards, especially when an emergency demand for improved seed is faced by the breeder.

Brazil↗
PubMed2004

Single-copy, species-transferable microsatellite markers developed from loblolly pine ESTs.

Microsatellites, or simple sequence repeats (SSRs), are usually regarded as the "markers of choice" in population genetics research because they exhibit high variability. The development cost of these markers is usually high. In addition, microsatellite primers developed for one species often do not cross-amplify in related species, requiring separate development for each species. However, microsatellites found in expressed sequence tags (ESTs) might better cross-amplify as they reside in or near conserved coding DNA. In this study, we identified 14 Pinus taeda (loblolly pine) EST-SSRs from public EST databases and tested for their cross-species transferability to P. contorta ssp. latifolia, P. ponderosa, and P. sylvestris. As part of our development of a P. contorta microsatellite set, we also compared their transferability to that of 99 traditional microsatellite markers developed in P. taeda and tested on P. contorta ssp. latifolia. Compared to traditional microsatellites, EST-SSRs had higher transfer rates across pine species; however, the level of polymorphism of microsatellites derived from ESTs was lower. Sequence analyses revealed that the frequencies of insertions/deletions and base substitutions were lower in EST-SSRs than in other types of microsatellites, confirming that EST-SSRs are more conserved than traditional SSRs. Our results also provide a battery of 23 polymorphic, robust microsatellite primer pairs for lodgepole pine.

Alleles↗
PubMed2002

Maintenance and impacts of an inoculated mer/luc-tagged Pseudomonas fluorescens on microbial communities in birch rhizospheres developed on humus and peat.

Antagonistic bacteria represent promising biocontrol agents for improving forest production in seedling nurseries or forest soils. The fate of an introduced mer/luc-tagged antagonistic Pseudomonas fluorescens 31K3 was monitored in the rhizosphere of silver birch (Betula pendula) seedlings grown in microcosms containing forest humus or nursery peat. The inoculated strain (10(8) cfu g(-1) soil) was unable to establish in significant numbers in either soil type and turned nonculturable in humus. Detection in both soils was possible only via luminescence of enrichment cultures 80 days post-inoculation. Despite low P. fluorescens survival, inoculation had a positive effect on seedling growth. Limited impact of inoculation on the indigenous microbial communities was identified following analyses of respiration and denitrification potential, community-level physiological profiles and molecular fingerprinting of fungi and eubacteria, and Pseudomonas community structures. The minor changes observed in the indigenous microbial communities, including mycorrhiza development, were not consistent between humus and peat growth substrates. It was concluded that the rhizosphere-related microbial communities developed in both of these highly organic soil systems are highly buffered against introduction of foreign bacteria.

Betula↗
PubMed2002

Large-scale effects of timber harvesting on stream systems in the Ouachita Mountains, Arkansas, USA.

Using Basin Area Stream Survey (BASS) data from the United States Forest Service, we evaluated how timber harvesting influenced patterns of variation in physical stream features and regional fish and macroinvertebrate assemblages. Data were collected for three years (1990-1992) from six hydrologically variable streams in the Ouachita Mountains, Arkansas, USA that were paired by management regime within three drainage basins. Specifically, we used multivariate techniques to partition variability in assemblage structure (taxonomic and trophic) that could be explained by timber harvesting, drainage basin differences, year-to-year variability, and their shared variance components. Most of the variation in fish assemblages was explained by drainage basin differences, and both basin and year-of-sampling influenced macroinvertebrate assemblages. All three factors modeled, including interactions between drainage basins and timber harvesting, influenced variability in physical stream features. Interactions between timber harvesting and drainage basins indicated that differences in physical stream features were important in determining the effects of logging within a basin. The lack of a logging effect on the biota contradicts predictions for these small, hydrologically variable streams. We believe this pattern is related to the large scale of this study and the high levels of natural variability in the streams. Alternatively, there may be time-specific effects we were unable to detect with our sampling design and analyses.

Animals↗
PubMed2002

Commercial medicinal plant extraction in the hills of Nepal: local management system and ecological sustainability.

This paper presents a case study from Jumla District, Nepal, investigating local management systems and ecological sustainability of commercial collection of a medicinal plant, spikenard (Nardostachys grandiflora DC, Valerianaceae), growing in alpine meadows. Interviews were undertaken with local collectors, traders, and district forest office staff, and the dynamics of people-plant interactions are analyzed using the Oakerson model. In all, 110 sample plots 1m square were laid out in three areas with differing collection and grazing pressures for recording of floristic composition and abundance of spikenard root biomass. Comparisons show significantly more root biomass in uncollected than collected areas with local management and the interpretation of differences in abundance is discussed. The combination of qualitative and quantitative investigations can provide a framework for the study of people-plant interactions, and this study can serve as first step in a compilation of cases to create a more detailed picture of local management systems of Nepali nontimber forest products in general and commercially collected medicinal and aromatic plants in particular.

Biomass↗
PubMed2002

The role of population projections in environmental management.

California and other regions in the United States are becoming more populated and ethnically diverse, and thus, ecological impacts on the wildland-urban interface are a significant policy concern. In a socioeconomic assessment focused on the geographic regions surrounding four national forests in southern California, population projections are being formulated to assist in the update of forest plans. In southern California, the projected trend of explosive population growth combined with increased ethnic and racial diversity indicates four challenges for environmental management. First, patterns of recreation use on wildlands are likely to change, and management of these areas will have to address new needs. Second, as land-management agencies face changing constituencies, new methods of soliciting public involvement from ethnic and racial groups will be necessary. Third, growth in the region is likely to encroach upon wildland areas, affecting water, air, open space, and endangered species. Fourth, in order to address all these concerns in a climate of declining budgets, resource management agencies need to strengthen collaborative relationships with other agencies in the region. How environmental managers approach these changes has widespread implications for the ecological sustainability of forests in southern California.

California↗