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Salmonberry and salal annual aerial stem production: the maintenance of shrub cover in forest stands
Get PDFAnnual sprouting of aerial stems and ramets enables populations of salmonberry (Rubus spectabilis Pursh), salal (Gaultheria shallon Pursh), and probably other forest shrubs to maintain dense covers (>20 000 stems/ha). We studied annual stem production of salmonberry on cut (all stems cut within 15 cm of the ground) and uncut (stems were not treated) plots for 8 years and salal for 5 years in the understories of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), alder, and riparian stands, as well as clearcuts, which are all common stand types in western Oregon. Mean salmonberry stem production on uncut plots ranged from 4.7 stems·m–2·year–1 (95% CI 2.9–7.4) in alder stands
and clearcuts to 1.6 stems·m–2·year–1 (95% CI 1.0–2.6) in conifer stands. Mean salal production was greater, ranging from 58 stems·m–2·year–1 (95% CI 25–135) to 8.6 stems·m–2·year–1 (95% CI 3.7–20.1) on uncut plots in clearcuts and unthinned Douglas-fir stands, respectively. Annual production of both species was somewhat greater on cut plots. Most stems produced in early spring die by December, but enough are recruited to replace mortality of older stems. Stem density was maintained for 8 years for salmonberry and 5 years for salal on both cut and uncut plots. Based on length of rhizomes and bud density we estimate that only 1–5% of the buds in the rhizomes are needed to support this annual stem production. Although these species sprout vigorously after their aerial stems are killed, disturbance is not necessary for maintaining a dense cover. It appears that, once established, salal, salmonberry, and probably other clonal forest shrubs can maintain a dense cover that can interfere with establishment of trees and other shrubs in canopy gaps or
other openings
Triage Law Enforcement: Societal Impacts on National Forests in the West
Get PDFUses of outdoor natural areas, like National Forests in the United States, have been undergoing change. Some changes, including criminal activities and domestic terrorism, may have quite important impacts to outdoor enthusiasts and managers. Activities include some relatively traditional management challenges, like arson and thefts, and newer challenges, such as domestic violence and murder. To better understand the prevalence and impacts of these activities, selected managers in the western United States were interviewed in summer and fall 1998. Results indicate criminal activities and domestic terrorism are found in both urban-interface and rural sites. The most prevalent challenges were arson, criminal damage, domestic violence, dumping of household trash and landscape materials, marijuana cultivation, satanic cult activity, and thefts. Not as prevalent but found in almost all study sites were body dumping, extremist group activity, gang activity, murders, and suicides. Managers felt that most outdoor recreationists were unaffected by the activities. Most managers noted the increasing prevalence and the costs to management in time, personnel, and in other ways. They noted that their job had ceased being one of natural resources law enforcement and became one of "city" law enforcement. The findings of the study raise serious issues that require additional research.KEYWORDS: Crime, Law enforcement, Domestic terrorism, CommunicationThis is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://www.springer.com/environment/environmental+management/journal/26
Conifer DBMagic: a database housing multiple de novo transcriptome assemblies for 12 diverse conifer species
Get PDFConifers comprise an ancient and widespread plant lineage of enormous commercial and ecological value. However, compared to model woody angiosperms, such as Populus and Eucalyptus, our understanding of conifers remains quite limited at a genomic level. Large genome sizes (10,000–40,000 Mbp) and large amounts of repetitive DNA have limited efforts to produce a conifer reference genome, and genomic resource development has focused primarily on characterization of expressed sequences. Here, we report the completion of a conifer transcriptome sequencing project undertaken in collaboration with the U.S. DOE Joint Genome Institute that resulted in production of almost 12 million sequence reads. Five loblolly pine (Pinus taeda) cDNA libraries representing multiple tissues, treatments, and genotypes produced over four million sequence reads that, along with available Sanger expressed sequence tags, were used to create contig assemblies using three different assembly algorithms: Newbler, MiraEST, and NGen. In addition, libraries from 11 other conifer species, as well as one member of the Gnetales (Gnetum gnemon), produced 0.4 to 1.2 million sequence reads each. Among the selected conifer species were representatives of each of the seven phylogenetic families in the Coniferales: Araucariaceae, Cephalotaxaceae, Cupressaceae, Pinaceae, Podocarpaceae, Sciadopityaceae, and Taxaceae. Transcriptome builds for each species were generated using each of the three assemblers. All contigs for every species generated using each assembler can be obtained from Conifer DBMagic, a public database for searching, viewing, and downloading contig sequences, the associated sequence reads, and their annotations.Keywords: Database,
Gene models,
Pinus,
Comparative phylogenomics,
Annotation,
Transcriptome,
Coniferale
Crown profile equations for stand-grown western hemlock trees in northwestern Oregon
Get PDFCrown profile equations were developed for stand-grown western hemlock (Tsuga heterophylla (Raf.) Sarg.) in northwest Oregon. The profile model uses a segmented approach, dividing the crown into an upper and lower portion at the point of the largest crown width (LCW). The model explains about 86% of the variation in crown width when LCW is known but only 66% when LCW is predicted using a model developed from a larger data set collected
in the same area as the data for developing the crown profile models were collected. The model can be adjusted using
measurements or predictions of LCW for western hemlock in other populations. Comparisons are made with the crown form of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
Effects of incising on lumber strength and stiffness: Relationships between incision density and depth, species, and MSR grade
Get PDFThis report describes the relationship of incising-induced strength loss in bending as a function of preservative treatment and incising pattern, density, and depth of penetration for various machine stress-rated (MSR) grades of full-size 2 by 4 Douglas-fir, Hem-Fir, and Spruce-Pine-Fir (South) dimension lumber. This study may represent a worst-case "incising effects" scenario: although the incising patterns and depths selected for study represent commonly used industrial practices, the incising process itself was performed on dry lumber, which is not the standard practice of the treating industry. As we had expected on the basis of Canadian results, incising affected bending properties, such as modulus of elasticity, modulus of rupture, and work to maximum load. Our results show that the combined incising-preservative effect on mean property values for lumber incised in the dry condition prior to treatment was in the range of a 0 to 10% loss in modulus of elasticity, 15% to 25% loss in modulus of rupture, and 30% to 50% loss in work to maximum load. The effect on properties at the lower end of the distribution, such as the allowable stress design value F, was equal to or less than that on mean properties for the three species groups evaluated. While these results specifically apply to only MSR-graded standard 38-mm- (nominal 2-inch-) thick lumber and to lumber incised in the dry condition prior to treatment, they do imply that the new U.S. design adjustments for C, in modulus of elasticity of 0.95 and F, of 0.85 may not be sufficient for incised and treated material used in dry in-service conditions.Keywords: grade,
mechanical properties,
Douglas-fir,
lumber,
preservative,
treatment,
Spruce-Pine-Fir (South),
Hem-Fir,
MSR,
incisin
Trophic cascades linking wolves (Canis lupus), coyotes (Canis latrans), and small mammals
Get PDFWhen large carnivores are extirpated from ecosystems that evolved with apex predators, these systems can change at the herbivore and plant trophic levels. Such changes across trophic levels are called cascading effects and they are very important to conservation. Studies on the effects of reintroduced wolves in Yellowstone National Park have examined the interaction pathway of wolves (Canis lupus L., 1758) to ungulates to plants. This study examines the interaction effects of wolves to coyotes to rodents (reversing mesopredator release in the absence of wolves). Coyotes (Canis latrans Say, 1823) generally avoided areas near a wolf den. However, when in the proximity of a den, they used woody habitats (pine or sage) compared with herbaceous habitats (grass or forb or sedge)– when they were away from the wolf den. Our data suggested a significant increase in rodent numbers, particularly voles (genus Microtus Schrank, 1798), during the 3-year study on plots that were within 3 km of the wolf den, but we did not detect a significant change in rodent numbers over time for more distant plots. Predation by coyotes may have depressed numbers of small mammals in areas away from the wolf den. These factors indicate a top–down effect by wolves on coyotes and subsequently on the rodents of the area. Restoration of wolves could be a powerful tool for regulating predation at lower trophic levels
Amino Acid Uptake in Arbuscular Mycorrhizal Plants
Get PDFWe examined the extent to which arbuscular mycorrhizal (AM) fungi root improved the acquisition of simple organic nitrogen (ON) compounds by their host plants. In a greenhouse-based study, we used quantum dots (fluorescent nanoparticles) to assess uptake of each of the 20 proteinaceous amino acids by AM-colonized versus uncolonized plants. We found that AM colonization increased uptake of phenylalanine, lysine, asparagine, arginine, histidine, methionine, tryptophan, and cysteine; and reduced uptake of aspartic acid. Arbuscular mycorrhizal colonization had the greatest effect on uptake of amino acids that are relatively rare in proteins. In addition, AM fungi facilitated uptake of neutral and positively-charged amino acids more than negatively-charged amino acids. Overall, the AM fungi used in this study appeared to improve access by plants to a number of amino acids, but not necessarily those that are common or negatively-charged
Risk analysis procedure for woodframe roof sheathing panel debris impact to windows in hurricanes
Get PDFThe assessment of losses during extreme events such as hurricanes is important for performance-based design of residential buildings. In this paper, a methodology for estimating the risk of debris impact, specifically roof sheathing panels, to windows as a result of hurricanes is introduced and applied to an illustrative example. The method is a combination of approaches on flat plate trajectories, numerical hurricane modeling, and statistical analysis of structural capacity. Within this methodology, one can estimate the risk of impact for one or more windows in a certain house group as a hurricane approaches and passes on a deterministic track as defined by the center of its eye. The impact risk is analyzed for the each hour making up the full hurricane duration rather than a single analysis using the blended (total) hurricane statistics. An illustration of the method is presented through a risk assessment of windborne debris impacts to windows in a house group located near the U.S. Gulf coast using a hurricane having the same track as hurricane Katrina in 2005. As a result, the probability of each window being hit by a roof sheathing panel (RSP) during each hour of the hurricane as well as during each hurricane is presented. The results quantify the risk from hour to hour during a hurricane and may serve to better orient houses in planned communities in hurricane prone regions as well as provide a better understanding of the interaction of hurricanes and structures.KEYWORDS: fragility, wind force, windborne debris, light-frame wood, hurrican
Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon
Get PDFDiameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100–300 years. The diameters of the trees at ages 100–300 years (D100–D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments
(PAIBA) of all trees increased for the first 30–40 years and then plateaued, remaining relatively high and constant from
age 50 to 300 years. Average PAIBA of the largest trees at ages 100–300 years were significantly greater by age 20 years than were those of smaller trees at ages 100–300 years. The site factors province, site class, slope, aspect, elevation,
and establishment year accounted for little of the variation observed in basal area growth at age 50 years and
D100–D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis
that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations
Interannual variability in the Northern California Current food web structure: Changes in energy flow pathways and the role of forage fish, euphausiids, and jellyfish
Get PDFThe Northern California Current (NCC) is a seasonally productive and open ecosystem. It is home to both a diverse endemic community and to seasonally transient species. Productivity and food web structure vary seasonally, interannually, and decadally due to variability in coastal upwelling, climate-scale physical processes, and the migratory species entering the system. The composition of the pelagic community varies between years, including changes to mid-trophic level groups that represent alternate energy-transfer pathways between lower and upper trophic levels (forage fishes, euphausiids, jellyfish). Multiple data sets, including annual spring and summer mesoscale surveys of the zooplankton, pelagic fish, and seabird communities, were used to infer NCC trophic network arrangements and develop end-to-end models for each of the 2003–2007 upwelling seasons. Each model was used to quantify the interannual variability in energy-transfer efficiency from bottom to top trophic levels. When each model was driven under an identical nutrient input rate, substantial differences in the energy available to each functional group were evident. Scenario analyses were used to examine the roles of forage fishes, euphausiids, and jellyfish (small gelatinous zooplankton and large carnivorous jellyfish) as alternate energy transfer pathways. Euphausiids were the more important energy transfer pathway; a large proportion of the lower trophic production consumed was transferred to higher trophic levels. In contrast, jellyfish acted as a production loss pathway; little of the production consumed was passed upwards. Analysis of the range of ecosystem states observed interannually and understanding system sensitivity to variability among key trophic groups improves our ability to predict NCC ecosystem response to short- and long-term environmental change.This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/00796611