Treesearch

A mathematical model is developed describing the natural smoldering of logs. It is considered the steady one dimensional propagation of infinitesimally thin fronts of drying, pyrolysis, and char oxidation in a horizontal semi-infinite log. Expressions for the burn rates, distribution profiles of temperature, and positions of the drying, pyrolysis, and smoldering fronts are obtained in terms of the smolder temperatures. An appropriate smolder transfer number is defined. Heat transfer by conduction, convection, and radiation inside the porous matrix of the log is considered, as are convection...

Equations to predict uncompacted crown ratio as a function of compacted crown ratio, tree diameter, and tree height are developed for the main tree species in Oregon, Washington, and California using data from the Forest Health Monitoring Program, USDA Forest Service. The uncompacted crown ratio was modeled with a logistic function and fitted using weighted, nonlinear regression. The models were evaluated using cross-validation. Mean squared error of predicted uncompacted crown ratio was between 0.1 and 0.15, overall bias was negligible, and correlation between the predicted and observed...

The effects of seasonal prescribed fire on the belowground ectomycorrhizal community and live fine root biomass were investigated before, 1 year after, and 2 years after prescribed underburning. Ectomycorrhizas were sampled from four replications of three treatments (fall underburning, spring underburning, and a nonburned.control) in a randomized complete block design. Samples were separated in two subsamples representing the upper 5 cm and lower 5 cm of a soil core. Molecular tools were used to distinguish 140 restriction fragment length polymorphism (RFLP) species of fungi directly from...

Understory response to fuel reduction treatments was evaluated in fire-adapted ponderosa pine-Douglas-fir forests in northeastern Oregon. Treatments included: no management (control), prescribed fall burning (burn), low thinning (thin), and low thinning followed by prescribed fall burning (thin/burn), replicated four times in a completely randomized design. Treatment effects were observed in the first growing season after burning and three seasons after thinning. Species richness of the understory vegetation was significantly lower in the thin than in the control, but Shannon-Weaver's...

Science does not exist in a vacuum, but reading scientific publications might make you think it does. Although the policy and management implications of their findings could often touch a much wider audience, many scientists write only for the few people in the world who share their area of expertise. In addition, most scientific publications provide information that is more like clues than complete answers. Making science truly meaningful in the formulation and implementation of natural resource management policy requires an additional step where the clues are fit together and polished so...

The debate over forest management has often portrayed management choices as tradeoffs between ecological and socioeconomic values. Scientists at Pacific Northwest (PNW) Research Station, along with their colleagues at universities and national forests, decided to look scientifically at the question: "Can we as a society produce wood products and other forest values in an environmentally acceptable and sustainable manner?" They translated the philosophical question into this research proposition: Commodity production (timber and nontimber forest products) and the other forest values...

In March and April of 2003, over 250 managers, researchers, and other participants gathered for a series of workshops at Oregon State University, the University of Arizona, and Colorado State University, near the largest wildfires of 2002. In response to the need for better understanding of large fires, the Wildland Fire Workshops were designed to create an atmosphere for quality interactions between managers and researchers and to accomplish the following objectives: (1) create a prioritized list of recommendations for future wildland fire research; (2) identify the characteristics of...

An economic assessment of an SLP5000 Diesel Micromill® was conducted to determine the maintenance and operation costs and the logistics of a mobile sawmill used to process small-diameter ponderosa pine. The Micromill® was first introduced in 1997 and has since received considerable attention. In 2003, the USDA Forest Service, Pacific Northwest Research Station conducted a detailed financial analysis of a Micromill® in Escalante, Utah. Productive and nonproductive time was recorded, and the feasibility and logistics of periodically moving the mill closer to the raw material source were...

Use of competition indices in the analysis of forestry experiments may improve detection and understanding of treatment effects, and thereby improve the application of results. In this paper, we compared the performance of eight indices in an analysis of a spacing trial of four Populus clones planted in pure and mixed clonal plots. Indices were included as covariates in analyses of variance and evaluated on their ability to decrease mean square error. Indices that were simple to calculate (i.e., required only diameter and spacing or distance information) decreased mean square error by as...

Stem irregularities can influence estimates of tree and stand attributes, efficiency of manufacturing processes, and quality of wood products. Eccentricity and fluting were characterized in young, managed western hemlock stands in the Oregon Coast Range. Sixty-one trees were selected from pure western hemlock stands across a range of age, site, and densities. The trees were felled and disks were removed from breast height, base of live crown, and various percentage-of-height locations along the bole. Indices of out-of roundness (OOR), pith-off-center (POC), and fluting severity (fluting...