bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Soil Water on Ground Fuel Availability
Authors: Samran Supparat , Woodard Paul M. , Rothwell Richard L.
Published: April 2024

A determination of ground fuel hydration was carried out in an aspen forest in Alberta, Canada. The objectives of the study were: (1) to determine the relative contribution of precipitation and soil water to the upper and lower ground fuel layers, (2) to determine if the moisture status of these layers was affected by slope position (bottom, mid, and top) or distance to a water body, and (3) to determine the drying rates for these two fuel layers. Results showed that upper and lower downed and dead fuels were hydrated by soil water as well as precipitation and that both sources contributed significantly to fuel moisture. During the period May 20 to September 20, 1990, precipitation and soil water contributed about 64% and 36% of the water to fuel moisture contents to the upper layer, and 41% and 59% to the lower layer, respectively. Fuel moisture contents varied significantly by slope position. The bottom slope position was always the wettest, while the fuel moisture contents in the other two positions were similar. In the absence of hydration, the upper and lower litter layers reached equilibrium moisture contents of 15% and almost 22%, respectively, but never dried out completely. For. Sci. 41(2):255-267.
Changes in Albedo of a Northern Hardwood Forest Following Clearcutting
Authors: Bourque Charles P.-A. , Daugharty David A. , Dickison Robert B. B. , Arp Paul A.
Published: April 2024

A semi-empirical model designed to stimulate seasonal and midsummer albedo of a northern tolerant hardwood stand following clearcutting was developed from field determinations conducted in west-central New Brunswick. In this model, changes in albedo are related to (1) vegetative regrowth (spreading of newly developing foliage over the cut area); (2) the gradual addition of vegetation layers within the forest canopy; and (3) seasonal variations from bud burst to fall. The field data indicated that (1) cutting reduced the albedo; (2) foliage regrowth rapidly increased the albedo to a maximum similar to that of a continuous single leaf layer within a few years after the cutting operation; (3) deepening of the canopy gradually decreased the albedo after its initial peak; and (4) albedo values were highest in early summer, except in the first year after the cutting operation. For. Sci. 41(2):268-277.
Potential Volume Yield for Mixed-Species Douglas-Fir Stands in the Northern Rocky Mountains
Authors: Sterba Hubert , Monserud Robert A.
Published: April 2024

A procedure for estimating potential volume yield is developed for stands containing dominant Douglas-fir in the Northern Rocky Mountains. Earlier work on site index and height growth and maximum stand density was the basis for deriving a stand form factor equation that provides potential volume estimates for a continuum of even- to uneven-aged mixed-species stands. The coefficients of this equation (which explained 84% of the variation) differ with respect to habitat type. The combination of asymptotic dominant height, potential basal area, and stand form factor allows for estimating potential total volumes as a function of site index and age of dominant Douglas-fir, habitat type, and the skewness of the dbh1.5-distribution (which characterizes stand structure). Potential volume yield levels vary with respect to habitat type and stand structure (skewness), indicating that much information on potential total volume is lost if only site index is used to measure productivity. These discrepancies between productivity estimates based on site index and potential volume are the result of different yield levels sensu Assmann existing within a given site index class. For the majority of habitat types, volume growth potential would have been underestimated using site index alone. For. Sci. 41(3):531-545.
Chlorophyll Fluorescence as a Measure of Cold Hardiness and Freezing Stress in 1 + 1 Douglas-Fir Seedlings
Authors: Fisker Susan E. , Rose Robin , Haase Diane L.
Published: April 2024

Two-year-old seedlings of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) from two seed lots with different levels of predicted cold hardiness were grown in separate nurseries. Seedlings were lifted every 4 wk from October 1991 through March 1992 and exposed to controlled freezing temperatures. Fluorescence emissions of the seedlings were measured before and 1 and 3 days after each freezing test. Destructive morphological assessments were made 7 days after freezing. Unstressed seedlings were measured during 6 additional test periods through September 1992. Chlorophyll fluorescence had a significant linear relationship to needle freezing damage and seedling survival, but there was no significant linear relationship between fluorescence of control seedlings and frost hardiness. The LT50 (lethal temperature for 50% of the seedlings) fluorescence measurements, however, tended to be lower before and higher after the seedlings were hardened off. These results indicate that chlorophyll fluorescence is capable of detecting nonvisible damage to seedlings. Continued research may show this to be a valuable tool for rapidly identifying damaged seedlings in nurseries and hence for aiding vital management decisions. For. Sci. 41(3):564-575.
Stochastic Frontier Estimation and Sources of Technical Efficiency in Southern Timber Harvesting
Authors: Carter Douglas R. , Cubbage Frederick W.
Published: April 2024

This research provides estimates of average industry and firm-specific technical efficiency using an econometric stochastic frontier production function for individual firms operating in the southern U.S. pulpwood harvesting industry in both 1979 and 1987. The stochastic frontier production function is capable of distinguishing deviations from the frontier due to uncontrollable stochastic elements, as well as provide a pure measure of technical efficiency. Results indicate that mean industry technical efficiency was nearly constant at 60% in both periods while frontier technical change averaged 1.8% annually over the period. Elements of human capital, technology, and production scale were influential in explaining efficiency differentials among firms. However, the relative influence of these factors changed over time. For. Sci. 41(3):576-593.
Compatible Estimation of Components of Forest Growth from Remeasured Point Samples with Restricted Generalized Least Squares
Authors: Lynch Thomas B.
Published: April 2024

Certain of the estimators which have been proposed for estimation of components of forest growth from remeasured horizontal point samples are not restricted to ensure that the initial volume estimate plus the growth estimate is equal to the final volume estimate. By viewing the initial volume, the final volume, and the components of growth as parameters in a linear model within the framework of restricted generalized least squares, estimates can be obtained which satisfy logical restrictions relating to forest growth. The model should be fitted to data obtained from a relatively large sample of points. Estimates of growth components are obtained on each point in the usual way. However, rather than simply averaging these estimates over all points, restricted generalized least squares can be used to estimate growth components in the linear model described above. Since the estimation technique can handle missing or extra points at the two measurement times, the technique can be applied to data obtained by sampling with partial replacement. For. Sci. 41(3):611-628.
Competitive Relations Between Douglas-Fir and Pacific Madrone on Shallow Soils in a Mediterranean Climate
Authors: Wang Zheng Qi , Newton Michael , Tappeiner John C.
Published: April 2024

A large area of Pacific Coast forests is characterized by shallow soil, with negligible rainfall in the growing season. This study explores water-seeking strategy on such a site. We studied availability of bedrock water and its effects on growth and ecophysiology of 11-yr-old planted Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and sprouting Pacific madrone (Arbutus menziesii Pursh). The study was carried out at three regulated densities of madrone sprouts on shallow (<50 cm) residual soils in southwest Oregon. Total bedrock water depleted from March to September, as observed in drill holes by neutron probe, did not differ significantly (P > 0.05) among three densities of madrone. However, cover in plots with the highest density of madrone (1322 sprout clumps/ha) depleted 50 mm of water from the 1.5 m layer by June, whereas vegetation on lower density treatments withdrew 15-28 mm by June, with later withdrawal distributed more uniformly through the growing season. Madrone density significantly affected basal diameter (P ≤ 0.0001) and height growth (P ≤ 0.002) of Douglas-fir. Madrone was consistently taller than Douglas-fir in all plots. The height of 11-yr-old madrone sprout clumps (424-465 cm) did not differ significantly among densities. Madrone leaf area index and biomass were higher at the high density of madrone than at medium density (P ≤ 0.045, LAI; P ≤ 0.001, biomass). Physiological advantages and rooting habits of madrone give it a competitive advantage over Douglas-fir in this area that it might not have if bedrock did not provide the principal water reservoir for summer growth. For. Sci. 41(4):744-757.
Design-Based Approaches to Horizontal-Point-Sampling
Authors: Eriksson Marian
Published: April 2024

Horizontal-point-sampling is formalized under three different unequal probability finite population sample designs and an infinite population formulation. All four approaches result in unbiased estimators for the per-area total and the variance of the total. It is argued that, of the four approaches, the infinite population formulation corresponds more closely to the need for per-area estimation and to the physical process of randomization. It results in components of change estimators that are additive over time as well as compatible with net change, and it is easier to explain. Regardless of the view accepted, it is demonstrated that horizontal-point-sampling can be formally described in a variety of ways. Examples provide insight into horizontal-point-sampling and into design-based sampling and the generality of the Horvitz-Thompson estimator. For. Sci. 41(4):890-907.
Procedures to Handle Inventory Cluster Plots that Straddle Two or More Conditions
Authors: Hahn Jerold T. , MacLean Colin D. , Arner Stanford L. , Bechtold William A.
Published: April 2024

We review the relative merits and field procedures for four basic plot designs to handle forest inventory plots that straddle two or more conditions, given that subplots will not be moved. A cluster design is recommended that combines fixed-area subplots and variable-radius plot (VRP) sampling. Each subplot in a cluster consists of a large fixed-area subplot for estimating area and tallying large trees, a microplot (small fixed-area subplot) for tallying small trees, and a variable-radius plot for tallying intermediate size trees. Subplots are assigned a condition class based on a classification algorithm. For subplots that straddle conditions, boundaries are mapped for area estimation, and the condition class of each tree is recorded. For some straddler subplots, there may be insufficient trees for specific conditions to allow unambiguous classification by computer algorithm. We discuss several possible solutions for this problem. For. Sci. Monogr. 31:12-25.
Dynamic Behavior of Douglas-Fir Tussock Moth Populations in the Pacific Northwest
Authors: Mason Richard R.
Published: April 2024

Larval densities of the Douglas-fir tussock moth (Orgyia pseudotsugata [McDunnough] [Lepidoptera:Lymantriidae]) were monitored annually to construct population time series in five different forest ecosystems. The time series were generated in parts of five national forests in three geographical provinces: the northern Blue Mountains of northeastern Oregon, the southern Cascade Range of south-central Oregon, and the northern Cascade Range of north-central Washington. The five series ranged in length from 12 to 23 yr and represented the broad numerical behavior of tussock moth populations in those provinces. Time series with the most variable fluctuations were recorded in the Blue Mountains, a region with a long history of regular tussock moth outbreaks. The least variable series was in the southern Cascades, an area with no previously documented outbreaks. Characteristics of series in the Blue Mountains and the northern Cascades were significantly correlated with one another, but not with those of the series in the southern Cascades. The density-dependent structure of each time Series was examined by autocorrelation and partial autocorrelation functions, which indicated that fluctuations were quasi-periodic, even at low densities, and that the most significant autoregressive process was a second-order feedback. Each time series was fit with a linear second- order autoregressive model and a discrete nonlinear logistic model with a single time delay. The models, based on density-dependent processes associated with preceding insect generations, accounted for an average of 44.6% of the variation in the time series. The remaining 55.4% of variation was due to unknown density-independent factors related to different years in the series. The models showed that the principal dynamics of tussock moth populations are generated by direct and delayed density-dependent processes. In outbreak-prone ecosystems, like those in the Blue Mountains and the northern Cascades, the primary regulation of insect numbers is by delayed feedback processes that result in populations sometimes having extreme fluctuations in density. Conversely, in nonoutbreak ecosystems, as in the southern Cascades, feedback is more balanced between both direct and delayed processes that stabilize populations at lower densities. External factors, like weather, also may influence the numerical behavior of populations to some extent, but their specific contribution to tussock moth dynamics is largely unknown. For. Sci. 42(2):182-191.
Nutritional Status and Deficiency Diagnosis of Pinus radiata Plantations in Spain
Authors: Romanyà Joan , Vallejo V. Ramon
Published: April 2024

Twenty-one plots of Pinus radiata D. Don were selected for nutritional diagnosis on the basis of parent material (nine different substrates) and climate (Atlantic and Mediterranean). After foliar analysis, nutritional diagnoses were conducted, using the critical level method and the DRIS system. The nutrient content in fresh litter (L horizon) was also measured, and nutrient levels of green pine needles were compared with leaves of three native hardwood species (Quercus ilex L., q. robur L. and Fagus sylvatica L.) growing near each pine plot. In most cases, deciduous trees showed higher nutritional levels than evergreen trees. Foliar levels of Ca were always higher in hardwood trees, irrespective of leaf longevity. Phosphorus (P) deficiency was the most common among pines (eight plots showed severe P deficiency). Nitrogen and magnesium deficiencies were also detected in a few cases. The DRIS system diagnosed a larger number of deficiencies than the critical level method, but after intercalibration both methods gave the same diagnosis. In the plots studied, litter analysis appeared to be an alternative to foliar analysis for P, S, Ca, and Mg diagnosis but not for N or K. For. Sci. 42(2):192-197.
Parental Rank Changes Associated with Seed Biology and Nursery Practices in Douglas-Fir
Authors: El-Kassaby Y. A. , Thomson A. J.
Published: April 2024

The impact of container-nursery management practices on the genetic composition of seedling crops was evaluated in an experimental study designed to determine the cumulative effects of: (1) differences in parental reproductive output in bulk seedlots, (2) parental variation in germination parameters (percent and speed), and (3)the interaction of these parameters with container-nursery practices of thinning and culling, and their effect on the genetic representation of parents in the resultant seedling crops. Results from the experimental study were compared to predictions of a stochastic simulation designed to estimate the consequences of differential parental seed contribution, and seed-germination percent and germination speed on indicators of crop performance. The experimental study was conducted on a Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) bulk seedlot that was representative of the differential seed contributions from 19 seed orchard parents. The nursery study included a total of 42,000 seeds. Seeds were sown at three seeds per cavity. Within the 14,000 cavities used, the identity of every seed was maintained throughout the study. Parents were compared based on: (1) changes in their rank order from sowing to postthinning and postculling status, and (2) relative performance from seed contribution to seedling production. Changes were observed in both assessments. Path analysis was used to determine the percent contribution of each factor to seedling production. It was determined that germination, thinning, and culling contributed 66, 20, and 14%, respectively, to seedling production, indicating the presence of three consecutive bottlenecks in the process. Single seed or individual family sowing in the nursery was recommended for seedling production to maintain genetic diversity. For. Sci. 42(2):228-235.
A Cross-National Investigation of Softwood Sawmill Marketing Strategies
Authors: Niemelä Juha S. , Smith Paul M.
Published: April 2024

The concept of marketing strategy at the interface between a company and its environment (customers, competitors, and stakeholders) has been a topic of lively discussion since the late 1970s. The marketing strategy concept has evolved from the fundamental marketing management questions regarding elements of the marketing mix to a more extensive concept whereby the ultimate objective is to gain competitive advantage.

This paper provides primary data collected from 102 companies in 3 nations/5 regions: Finland, Western Coast USA, Western Inland USA, Coastal British Columbia, Canada, and Interior, British Columbia, Canada. Empirical testing was conducted by measuring a firm's marketing strategy, determined by making strategic decisions concerning products, customers, market areas, and marketing competences. Factor analysis discovered five underlying dimensions of market strategy which were subsequently measured and plotted graphically by the five producing regions included in the study. Comparisons and contrasts of the marketing strategies of the various regions are examined and discussed. For. Sci. 42(3):290-299.
Sustainable Forest Ecosystems and Management: A Review Article
Authors: Toman M. A. , Ashton P. M.S.
Published: April 2024

Concerns about the sustainability of forest resources and ecosystems have been expressed almost from the beginning of modern studies of forest management by ecologists, biologists, economists, and other specialists. However, the focus of this concern has gone through several transformations. Environmental scientists have emphasized the maintenance of forest ecosystems in the face of different types of human intervention. Economists and forest managers, on the other hand, have emphasized the capacity of forest systems to provide valued ongoing flows of goods and services for human societies.

This paper takes stock of forest resource and ecosystem sustainability from both ecological and economic perspectives. It seeks to identify how these disciplinary perspectives contribute to a better understanding of sustainability, and where the most significant conceptual and factual gaps are found. Of particular interest are two related themes: how economic efficiency and sustainability may differ in their implications for forest system management, and how criteria for forest system sustainability are related to the scale of management decisions (e.g., individual forest site versus region versus the global biosphere). For. Sci. 42(3):366-377.
Projection Variance Partitioning of a Conceptual Forest Growth Model with Orthogonal Polynomials
Authors: Gertner George , Parysow Pablo , Guan Biing
Published: April 2024

An uncertainty analysis was performed for a conceptual forest growth model for red pine (Pinus resinosa Ait.). Low order orthogonal response surface models were developed to predict the variance of projections made with the conceptual model. Based on these orthogonal response surface models, it was possible to partition the variance of the projections. Approximate error budgets were developed, and the power of hypotheses tests based on model predictions were assessed. For. Sci. 42(4):474-486.
Results from Genetic Tests of Selected Parents of Douglas-Fir (Pseudotsuga menziesii [Mirb.] Franco) in an Applied Tree Improvement Program
Authors: Stonecypher R. W. , Piesch R. F. , Helland G. G. , Chapman J. G. , Reno H. J.
Published: April 2024

Results from genetic tests, and genotype by environment interaction studies in six low-elevation breeding zones of Weyerhaeuser Company's Western Washington and Oregon Douglas-fir tree improvement program are summarized. Phenotypic selection in natural stands resulted in a 5% improvement in juvenile height over nonselect seed lots. Comparisons with nonselect sources, of offspring from parents in the top 50% performers in tests, indicated a 10% increase for the same trait. Seed produced in a 50% rogued seed orchard is thus expected to provide improved planting stock with a gain of 10% in juvenile height growth. Several select parents are producing offspring that are consistently performing in excess of 10% over nonselects.

Estimates of breeding zone, breeding zone by location, and family by location interaction effects are small relative to family and planting location effects. Tests of families established on environmentally diverse sites indicate a striking lack of large family by planting location interaction. In tests showing statistically significant interactions, such interactions are caused by a relatively small number of families. We did observe earlier budbreak and a higher spring frost susceptibility of Oregon sources established on Washington sites.

We conclude that allocation and utilization of select families within Weyerhaeuser's Oregon and Washington ownership should not be constrained by the currently defined breeding zone boundaries, but based on parental performance and stability for growth and adaptive traits in general. We further suggest that the necessity for maintaining separate breeding zones, within Washington and Oregon, in subsequent cycles of recurrent selection is questionable.

Average individual tree heritability, from 65 6-parent disconnected diallels, is 0.13 for age 6 and age 8 height. Dominance genetic variance is estimated to be one-half that of additive genetic variance for the same traits.The environmental designs and test establishment methods used resulted in acceptable levels of statistical precision for juvenile growth traits. Individual test least significant range values (LSR) resulted in significant family mean percent height differences of 8 to 26, and averaged 13% for diallels, and full-sib and half-sib tests. For. Sci. Monogr. 32:1-35.
An Optimization Approach to Area-Based Forest Pest Management Over Time and Space
Authors: Hof John , Bevers Michael , Kent Brian
Published: April 2024

This paper discusses spatial optimization approaches to managing aggressively reproducing and dispersing pests. The relevant land planning area is divided into cells, and pest growth and dispersal across those cells are accounted for in integer programs that include choice variables for applying control treatments to those cells. Two model formulations are developed and demonstrated in a simple case example: one that assumes no limit to host capacity and one that assumes a limit to host capacity accumulated over time. The formulation with no host capacity limit is shown to be potentially unrealistic if control treatments are not limited. Different objective functions and amounts of control treatment result in optimal strategies that vary from immediate containment near the pest's origin to delayed containment at an area away from the pest's origin. Both formulations are difficult to solve, reflecting the exploratory nature of this paper. For. Sci. 43(1):121-128.
Wildlife Conservation Planning Using Stochastic Optimization and Importance Sampling
Authors: Haight Robert G. , Travis Laurel E.
Published: April 2024

Formulations for determining conservation plans for sensitive wildlife species must account for economic costs of habitat protection and uncertainties about how wildlife populations will respond. This paper describes such a formulation and addresses the computational challenge of solving it. The problem is to determine the cost-efficient level of habitat protection that satisfies a viability constraint for a sensitive wildlife population. The viability constraint requires a high probability of attaining a population size target. Because of the complexity of wildlife prediction models, population survival probabilities under alternative protection plans must be estimated using Monte Carlo simulation. The computational challenge arises from the conflicting effects of sample size: fewer replications used to estimate survival probability increases the speed of the search algorithm but reduces the precision of the estimator of the optimal protection plan. Importance sampling is demonstrated as a simulation technique for reducing estimator variance for a given sample size, particularly when the tail of the population distribution is of critical importance. The method is demonstrated on a hypothetical problem involving gray wolf management in the Great Lakes region of the United States. In comparison to random sampling, importance sampling produces a 21-fold reduction in the variance of the estimator of the minimum-cost protection plan. Results from the optimization model demonstrate the extreme sensitivity of the minimum-cost protection plan to the structure of the growth model and the magnitude of environmental variation. This sensitivity is not widely recognized in the literature on wildlife habitat planning and is a strong reason for using optimization methods that can handle stochastic population models with a wide range of structures. For. Sci. 43(1):129-139.
Using Pheromone-Baited Traps To Control the Amount and Distribution of Tree Mortality During Outbreaks of the Douglas-Fir Beetle
Authors: Ross Darrell W. , Daterman Gary E.
Published: April 2024

Multiple-funnel traps baited with strong aggregation pheromone lures were placed throughout three 259 ha plots in northeastern Oregon during an outbreak of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins. Mean numbers (± SEM) of Douglas-fir beetles collected per plot for the entire flight periods of 1992 and 1993 were 277,921 ± 40,447 and 268,834 ± 37,088, respectively. Mean numbers (± SEM) of the most abundant predator, Thanasimus undatulus (Say), collected per plot in 1992 and 1993 were 43,527 ± 3,553 and 35,652 ± 3,514, respectively. Douglas-fir beetle-caused tree mortality was concentrated around the trap sites in the treated plots, even though traps were located an average of 40 m from the nearest host tree. Managers can influence the spatial distribution of tree mortality during an outbreak by selective placement of traps across the landscape. Selective trap placement, plus the removal of trapped beetles from the population, may reduce tree mortality within the general area. For. Sci. 43(1):65-70.
Inoculation of Tree Roots with Plant Growth Promoting Soil Bacteria: An Emerging Technology for Reforestation
Authors: Chanway C. P.
Published: April 2024

Seedling root systems are colonized heavily by asymbiotic soil bacteria, many of which have the potential to influence plant growth significantly. A heterogeneous group of these microorganisms is well known for their ability to colonize roots and stimulate growth of agricultural plant species, sometimes doubling seedling biomass accumulation only a few weeks after inoculation, but more usually resulting in less spectacular biomass gains (e.g., 15%-30% greater than uninoculated controls within a growing season). Plant growth promoting soil bacteria may exert such effects through a variety of mechanisms, and include microorganisms that stimulate seedling emergence or infection by symbiotic fungi and bacteria. Other plant beneficial soil bacteria possess biological control activity or are capable of transforming plants genetically. Inoculation of tree seedlings with such bacteria before outplanting would be an inexpensive, environmentally benign, and easily applied nursery treatment, but comparatively little work has been performed with these microorganisms in forestry. Recent results with various tree species, however, indicate that seedling performance can be significantly enhanced through bacterial inoculation of root systems: pine and spruce biomass increased 32%-49% 1 yr after inoculation and outplanting at a reforestation site. In addition, infection by desired species of ectomycorrhizal fungi can also be enhanced by inoculation with certain strains of root colonizing bacteria. Results from studies performed with beneficial asymbiotic tree root associated bacteria are reviewed in this article in relation to the possible uses of such microorganisms for artificial forest regeneration. For. Sci 43(1):99-112.
Using Tabu Search To Generate Stand-Level, Rule-Based Bucking Patterns
Authors: Laroze Andre J. , Greber Brian J.
Published: April 2024

A Tabu Search (TS) heuristic was developed for generating easily implementable bucking rules that are applicable to entire stands (as opposed to individual stem classes), and for selecting the rule-set that provides the best feasible solution (given log prices and market constraints). The tabu restrictions used for guiding the search process are based on the frequency of the export logs' attributes, and the profit corresponding to the local optima found during the search. Parallel tabu lists of different time-spans were considered. The aspiration criterion for revoking a tabu status consisted of improving upon the best feasible solution. The model was applied to a set of radiata pine (Pinus radiata, D. Don) stands, considering different market constraints and price sets. The TS approach leads to bucking outcomes that are reasonably close, in profit terms, to the solutions obtained by an integer programming model designed for selecting the optimal set of stem-specific bucking patterns. For. Sci. 43(2):157-169.
A Qualitative Comparison of Fire Spread Models Incorporating Wind and Slope Effects
Authors: Weise David R. , Biging Gregory S.
Published: April 2024

Wind velocity and slope are two critical variables that affect wildland fire rate of spread. The effects of these variables on rate of spread are often combined in rate-of-spread models using vector addition. The various methods used to combine wind and slope effects have seldom been validated or compared due to differences in the models or to lack of data. In this study, rate-of-spread predictions from the Canadian Fire Behavior Prediction (FBP) system, McArthur's Mark V forest fire danger meter, the Rothermel empirical model, and the Pagni and Peterson physical model were compared with spread rates observed in a designed laboratory experiment in which wind velocity and slope were varied. Methods of combining wind and slope developed by Albini, McAlpine, and Rothermel were applied to two forms of Rothermel's model. Rothermel's model (original and modified) coupled with Albini's method and Pagni's model predictions closely reproduced the observed shape of the rate-of-spread response to wind and slope. Rothermel's method and McAlpine's method worked well in all cases except in upslope spread with opposed flow. However, Rothermel's model failed to predict a nonzero rate of spread in fuel beds with moisture contents of 35%. Possible causes of overprediction by McArthur's model and the FBP model included: (1) application of equations derived from full-scale fires to laboratory-scale fires, (2) improper selection of fuel type to represent artificial fuel beds, and (3) inaccurate estimation of wind velocity 10 m above the vegetation surface using a logarithmic profile. For. Sci. 43(2):170-180.
Aggregation Procedures in Forest Management Planning Using Cluster Analysis
Authors: Weintraub Andrés , Sáez Guillermo , Yadlin Marisa
Published: April 2024

Typical linear programming models used in forest planning can be very large. It is often of interest to analyze more compact, less detailed versions. One form of reducing the size of the problem is through an aggregation process. One way in which this has been done is through a column aggregation process, where sets of similar columns are replaced by one representative. A second alternative is to aggregate the original data, in which case the stands and management alternatives are grouped before building a model. Typical approaches for the aggregation processes have been analytical. We present an alternative approach for aggregation based on cluster analysis. Computational results for both types of aggregation show that using cluster analysis can be advantageous. For. Sci. 43(2):274-285.
Exploring the Error Structure of Taper Equations
Authors: Williams Michael S. , Reich Robin M.
Published: April 2024

Much work has been done fitting taper equations to specific tree bole shapes, but few researchers have investigated what effect the correlated error structure has on the fit of a taper equation. The Max and Burkhart (1976) taper equation was used in conjunction with a number of equations which modeled the covariance structures. The equations proposed were continuously differentiable, which simplifies the fitting process, and selected to minimize the number of parameters. A maximum likelihood method was proposed to fit these equations and test the statistical significance of the correlated errors. Accounting for the correlated errors structure in the equation fitting process significantly improved fit. Tests showed a small, but significant, bias of 1.05% (± 0.143%) when the correlated errors were ignored. For. Sci. 43(3):378-386.
Clonal Variation in Susceptibility of White Birches (Betula Spp.) to Mammalian and Insect Herbivores
Authors: Rousi Matti , Tahvanainen Jorma , Henttonen Heikki , Herms Daniel A. , Uotila Ilari
Published: April 2024

Resistance of small micropropagated plantlets and seedlings of white birch (Betula pendula Roth and B. pubescens Ehrh.) to hares (Lepus timidus L.), voles (Microtus agrestis L.) and weevils (Phyllobius and Polydrosus spp.) was determined. Field and cafeteria experiments were conducted over 2 yr period at several locations near Punkaharju Forest Research Station, Eastern Finland. There were significant differences among clones and seedlots (forest seed origins) in susceptibility to hares, voles, and weevils. One of the eight clones studied in detail was resistant to most tested agents (clone 39), whereas two clones were susceptible to each agent (clones 36 and JR/1). However, there was only one significant correlation (hare vs. Polydrosusweevil) among rankings of clones in susceptibility to different pests. Generally the differences among clones were similar in different experimental situations, indicating a genetic basis to variation in resistance. No difference in the susceptibility was observed between seedlots from natural forest and micropropagated plantlets from rapidly growing plus trees, suggesting that selecting for rapid growth did not compromise resistance as predicted by some theories. For. Sci. 43(3):396-402.
Choosing Prices to Optimally Buck Hardwood Logs with Multiple Log-Length Demand Restrictions
Authors: Pickens James B. , Throop Scott A. , Frendewey James O.
Published: April 2024

The purpose of this article is to present a hierarchical optimization approach that selects prices which, when used in a single stem bucking optimization model, produce a specified mix of logs by grade and length. The model is developed to address the demand constrained optimal bucking situation for northern hardwoods. The demand constraints are minimum percentages needed in four log lengths [3.0 m (10 ft), 3.7 m (12 ft), 4.3 m (14 ft), and 4.9 m (16 ft)] to meet order requirements from veneer buyers. There are two levels in the hierarchical optimization system: at the lower level, a dynamic programming model is used to optimize the value of each individual tree, while the upper level is a linear programming model which finds one or more sets of prices, each used some portion of the time, that produce the required product mix in the lower level model. The hierarchical model is solved iteratively until a single set of prices satisfies all demand constraints. This approach is distinctly different than traditional approaches, which pass different information between the upper and lower level models to solve two-level optimization problems. The parameters passed in traditional approaches are shadow prices in one direction and production levels in the reverse direction. The model developed could be adapted to other species and log grading rules whenever several competing demand constraints exist. Furthermore, the approach could be adapted to a wide range of hierarchical planning applications where inputs, and therefore the production possibilities curve, are fixed and constraints apply. For. Sci. 43(3):403-413.
Relating Site-Specific Weather Data to Regional Monitoring Networks in the Lake States
Authors: Kuuseoks E. , Liechty H. O. , Reed D. D. , Dong J.
Published: April 2024

Meteorological variables most frequently used in ecological studies include, or are derived from, daily precipitation and air temperature. In many studies, weather data from the nearest permanent weather station are used as surrogates for on-site measurements. This study discusses the problems with this approach and illustrates methods for developing regression equations for calculating site-specific daily minimum, average, and maximum temperatures, and precipitation amount from regional monitoring information. Meteorological data were collected at four sites along a 650 km climatic gradient from Houghton County (47°N, 89°W) to Oceana County (43°N, 86°W), Michigan. Data from several National Oceanic and Atmospheric Administration (NOAA) stations within 40 km of each study site were related to measurements made at each site. Predictive ability was improved by using information from more than one NOAA station to predict on-site temperature. No increase in predictive ability resulted from including information from more than a single station when predicting precipitation. For the majority of the sites and climate variables, the best relationships were not obtained by using the nearest NOAA station; variables such as the relative distance from large bodies of water or elevation appeared to be influential. Since distance between two locations is rarely the most important factor governing the relationship between their climates, the use of the nearest weather station is not the best method to describe weather conditions on specific sites of interest. For. Sci. 43(3):447-452.
Breeding Objective for Plantation Eucalypts Grown for Production of Kraft Pulp
Authors: Greaves Bruce L. , Borralho Nuno M. G. , Raymond Carolyn A.
Published: April 2024

A long-term production function for unbleached eucalypt kraft pulp, incorporating all growing, harvesting, transport, and pulping costs, and variable capital and operating costs, was used to determine the economic importance of standing volume, basic density, pulp yield, and stem form. The value of each trait to breeding was defined as the relative improvement toward the objective (of minimizing total pulp cost) for a given selection intensity when selecting for each trait individually. For genetic parameters typical of eucalypts, and with the aid of simulated first-geneneration eucalypt populations, density and standing volume were the most important traits, providing the greatest savings in total pulp cost. Combined selection using density and volume provided 95% of the gains possible from an index involving all traits (density, volume, pulp yield, and form). Selection for pulp yield alone provided only 53% of the savings possible from selection for density, and improvement in stem form had negligible effect on total pulp cost. For. Sci. 43(4):465-472.
Comparing the Economic Value of Reducing Fire Risk to Spotted Owl Habitat in California and Oregon
Authors: Loomis John B. , González-Cabán Armando
Published: April 2024

To increase the range of natural resource values considered in the USDA Forest Service fire management analysis system, a combined telephone contact-mail booklet-telephone interview of California and New England households regarding their willingness to pay for reducing fire intensity and acres burned in California and Oregon's spotted owl habitat located in old growth forests was performed. Using a multiple bounded dichotomous choice format, annual willingness to pay of $79 per California household and $46 per New England household was estimated for a 20% reduction in acreage burned in California. For the same percentage reduction in fire in Oregon's old growth forest the value is $59 per California household and $45 per New England household. For a combined California and Oregon Program, California households would pay $95 annually, while New England households would pay $61. This illustrates the importance of national programmatic valuation of the USDA Forest Service's fire control program in old growth forests, rather than state by state surveys which miss substitution effects. This analysis also demonstrates that households benefit from and support fire protection of old growth forests in states other than their own. For. Sci. 43(4):473-482.
Uncertainty and Forest Land Use Allocation in British Columbia: Vague Priorities and Imprecise Coefficients
Authors: Ells Arlene , Bulte Erwin , van Kooten G. Cornelis
Published: April 2024

Recently, increasing weight has been placed on nontimber values in forest management. Both the multiple objectives and the parameters that support decision making in forestry are often imprecise and vague. In this paper, the concepts of fuzzy set theory are explained and then applied to the problem of allocating public forestland on Vancouver Island among competing land uses. Two principal sources of fuzziness are identified--those related to uncertainty in classification (specification of management objectives) and those related to uncertainty concerning how actions affect objectives (imprecise technical coefficients). By comparing the results of classical and fuzzy decision models, we conclude that the latter approach can be judged an improvement over the former. The fuzzy land-use allocation appears to be more consistent with the political decision making process, which relies on consultation and consensus-seeking among various interest groups, that has evolved in British Columbia. The analysis also yields insights into the robustness of outcomes and suggests priority areas for further research. For. Sci. 43(4):509-520.
Genetic Parameters and Selection Efficiencies in Resistance to Western Gall Rust, Stalactiform Blister Rust, Needle Cast, and Sequoia Pitch Moth in Lodgepole Pine
Authors: Wu Harry X. , Ying Cheng C.
Published: April 2024

Genetic variances, heritabilities, and between-trait genetic correlations in resistance to western gall rust (Endocronartium harknessii), stalactiform blister rust (Cronartium coleosporioides), needle cast (Lophodermella concolor), and sequoia pitch moth (Synanthedon sequoiae) (Lepidoptera: Sesiidae) were investigated in a 21-yr-old lodgepole pine (Pinus contorta spp. latifolia) provenance-family trial with 778 wind-pollinated families in interior British Columbia. Selection efficiencies in expected improvement in resistance were compared among mass, family, sequential family-and-within-family, and combined family/individual index selection. Efficiencies in multitrait selection for overall resistance to the four pests based on different selection indices were also compared. Individual heritability for incidence of western gall rust was 0.50, stalactiform blister rust 0.32, needle cast 0.30, and sequoia pitch moth 0.21. Family mean heritabilities ranged from 0.39 to 0.65. The genetic correlation between incidence of sequoia pitch moth and stalactiform blister rust was 0.89, and between pitch moth and western gall rust 0.25. The genetic gain estimates from mass selection for resistance to the four pests varied from 14 to 31% at a 13% selection rate. On average, combined family/individual index selection was 5% more efficient than mass selection, and family and sequential family-and-within-family selection was about 38% and 16% less efficient than mass selection, respectively. Substantial improvement can also be expected from provenance selection. Multitrait index selection for overall resistance excluding sequoia pitch moth data was nearly as efficient as the full index. Indirect selection for resistance to sequoia pitch moth based on resistance for stalactiform blister rust was more efficient than direct selection. Selection for resistance showed little adverse effect on growth. For. Sci. 43(4):571-581.
Notes: Optimal Economic Selection of Road Design Standards for Timber Harvesting Operations―A Corrected Analytical Model
Authors: Greulich Francis E.
Published: April 2024

A theoretical development is given that corrects a long-accepted analytical model used in road system design. The model assumes that a forested area with uniform conditions of road construction is to be accessed by truck road for timber harvest. A discrete number of specified road design standards are available. Each design standard has known costs per unit length associated with road construction and use. The resulting total cost for any segment of the road when constructed to a given standard and used for timber haul depends fundamentally on the volume of timber transported over that segment. Transported volumes may vary along the length of the road, however, thus changing the associated costs. The emended economic decision rules for specifying road standards along the entire length of the road even as haul volumes change are developed. Examples are given. For. Sci. 43(4):589-594.
Estimating Tree Grades for Southern Appalachian Natural Forest Stands
Authors: Prestemon Jeffrey P.
Published: April 2024

Log prices can vary significantly by grade: grade 1 logs are often several times the price per unit of grade 3 logs. Because tree grading rules derive from log grading rules, a model that predicts tree grades based on tree and stand-level variables might be useful for predicting stand values. The model could then assist in the modeling of timber supply and in economic optimization. Grade models are estimated for ten species groups found in the southern Appalachians, using data from several thousand trees and permanent plots in the USDA Forest Service's Forest Inventory and Analysis (FIA) database. The models correctly predicted grades of a majority of trees in both a test and a validation data set, and predictions of grade proportions across a sample of the population were usually within three percentage points of actual grade proportions. But success of models varied across species and diameter groups. Considering several measures of modeling success, the most accurate models were those predicting tree grades for softwoods and larger hardwoods. For. Sci. 44(1):73-86.