bluuebunny/crossref_metadata_2025_split huggingface dataset:
Price and Welfare Effects of Catastrophic Forest Damage From Southern Pine Beetle Epidemics
Authors: Holmes Thomas P. 
Published: April 2024

Abstract
Southern pine beetle (Dendroctonus frontalis) epidemics are periodically responsible for catastrophic levels of mortality to southern yellow pine forests. Traditional forest damage appraisal techniques developed for site specific economic analysis are theoretically weak since they do not consider aggregate impacts across ecosystems and related markets. Because the traditional model estimates losses only to producers with damaged forests, it provides misleading information from a distributional standpoint by ignoring impacts on producers with undamaged forests and timber consumers. An economic model of timber supply and demand is introduced and used to develop a new technique for estimating short-run market level impacts of catastrophic forest damages. The null hypothesis that catastrophic disruption of forest ecosystem production has no effect on timber markets is tested using intervention analysis and data on the recent Texas-Louisiana epidemic. Parameter estimates are used to compute short-run changes in economic welfare for producers on damaged forests, producers on undamaged forests, and timber consumers. Principal findings are: (1) changes in social welfare resulting from catastrophic damage to standing timber across forest ecosystems requires market-level analysis, and (2) the net change in economic welfare resulting from insect epidemics is unambiguously negative. For. Sci. 37(2):500-516.
Self-Thinning and Stand Density
Authors: Zeide Boris 
Published: April 2024

Abstract
Does the actual line of serf-thinning converge with the upper boundary of stand biomass in the course of stand development? This question is the source of continuing arguments about serf-thinning of forest stands. The relationship between average crown length and crown width can provide a solution to this question. If the lines diverge and horizontal canopy closure diminishes, then crown length would increase faster than crown width. Empirical data show that, indeed, the growth rate of crown length exceeds that of crown width. This fact indicates that the upper boundary of stand biomass is not the asymptote of self-thinning. Although the limiting line cannot be observed, it can be determined analytically. The notion of limiting density might be helpful in quantifying self-thinning, degree of disturbance, and stand density. For. Sci. 37(2):517-523.
The Structure of Forestry Production: Short-Run and Long-Run Results
Authors: Wear David N. , Newman David H. 
Published: April 2024

Abstract
This paper extends the study of regional forestry production to address long-run production possibilities using a restricted profit function approach. The model consists of two outputs, sawtimber and pulpwood; one variable input, regeneration effort; and two quasi-fixed inputs, land and growing stock. Estimation is performed using cross-sectional data of industrial timber production in the southeastern United States. Estimated values include own- and cross-price elasticities between inputs and outputs, Hicksian elasticities of substitution, shadow prices of the quasi-fixed factors, and long-run Marshallian elasticities. While short-run supply elasticities are consistent with earlier studies, long-run results show much greater supply responses as land and management inputs are given time to adjust. These results also suggest that ambiguous results regarding pulpwood and sawtimber substitutability found in previous studies can be explained by a shift from complementarity in the short run to substitutability in the long run. For. Sci. 37(2):540-551.
Relationships Between the Diameter Distributions Before and After Thinning
Authors: Murray D. M. , von Gadow K. 
Published: April 2024

Abstract
Specific equations to predict the change in diameter with thinning are derived from the statistical consistency conditions that ensure that the thinned and the remaining distributions add up exactly to the before thinning distribution. These equations contain two parameters, the location separation parameter and the scale separation parameter, that quantify the degree of selectivity of a thinning operation. For. Sci. 37(2):552-559.
Efficiency of Early Selections for Stem Volume and Predictions of Size Distributions of Selections in a Red Pine Spacing Trial
Authors: Magnussen Steen 
Published: April 2024

Abstract
Simulated phenotypic selections for superior stem volume at age 34 were carried out in a red pine spacing trial between age 10 and age 34. The efficiency of selections increased exponentially with selection age and with diminishing initial spacing. Interactions between spacing, age, and the intensity of selection modified the overall efficiency of early selections. The probability that a tree would remain in a given relative size class during a 2-or 4-year-period increased with age when the initial spacing was less than 2.1 m. Wider spacings induced a decline in these probabilities. Realistic predictions of future size class distributions of trees selected for superior size at age 10 were generated from a maximum of 4 years growth information with the help of Markov chains (transition probability matrices). Age 34 standardized means of early selections could be estimated within 2% from a quadratic response surface with age, spacing, and selection intensity (%-select) as independent variables. For breeding purposes, selections at age 10 appeared more attractive than later selections. Predictions of age 10 to age 34 years correlations of stem volume based on these Markov chains produced realistic results for plantations planted at a 3.0 m square spacing and closer. For. Sci. 37(2):593-612.
Genetic Variation in Nitrogen Use Efficiency of Loblolly Pine Seedlings
Authors: Li Bailian , McKeand S. E. , Allen H. L. 
Published: April 2024

Abstract
Seedlings of 23 open-pollinated loblolly pine (Pinus taeda L.) families were grown in a greenhouse at two nitrogen (N) levels (5 and 50 ppm). Differences among families for components of N use efficiency (NUE) were evaluated from measurements of biomass and N accumulation in different parts of seedlings. NUE, defined as stem biomass produced per unit of N applied, was partitioned into two major components: uptake and utilization efficiencies. Family differences were detected for NUE and its two components at low N and for utilization efficiency at high N. Heritability estimates indicated that NUE traits were under a moderate to high degree of genetic control. NUE and its components were generally positively correlated with root and shoot growth of seedlings. Families with more nitrogen (high uptake efficiency) had greater root length and stem height at low N but not at high N. Strong correlation of seedling root and shoot traits with NUE components indicated that genetic differences in N use may reflect differences in seedling growth. The relative contribution of uptake or utilization efficiency to the variation in NUE was different at the two N levels. At the high N level, differences among families for NUE were due largely to variation in utilization of absorbed N, while uptake and utilization efficiencies contributed equally to the variation in NUE at the low N level. Furthermore, some families with similar levels of NUE showed large differences in the relative contribution of uptake and utilization efficiency. For. Sci. 37(2):613-626.
A Bayesian Belief Network Advisory System for Aspen Regeneration
Authors: Haas Timothy C. 
Published: April 2024

Abstract
The probability-based Bayesian Belief Network (BBN) methodology is demonstrated to be an alternative to rule-based methods in forest management expert systems. Unlike a rule-based system, a BBN incorporates uncertainty in the knowledge and input data without sacrificing knowledge modularity. After reviewing the graph and probability theory needed to define a BBN as a joint distribution representable by a directed acyclic graph, an 11-variable network modeling Rocky Mountain aspen sucker density response to different management options is constructed. For a typical aspen site, the model's estimated marginal probabilities of sucker response exhibit values consistent with those expected. Finally, a BBN is shown to be fairly tolerant to small parameter errors, and a new method is given for BBN model validation. For. Sci. 37(2):627-654.
The Influence of Herbaceous Weed Control and Seedling Diameter on Six Years of Loblolly Pine Growth—A Classical Growth Analysis Approach
Authors: Britt J. R. , Mitchell R. J. , Zutter B. R. , South D. B. , Gjerstad D. H. , Dickson J. F. 
Published: April 2024

Abstract
Classical growth analysis equations were applied to three loblolly pine (Pinus taeda L.) seedling ideotypes (determined by groundline diameter) that were subjected to either 2 years of complete herbaceous weed control (low weed abundance: LWA) or no herbaceous weed control (high weed abundance: HWA). For the first 2 growing seasons, seedlings of the LWA treatment had greater mean relative growth rate (RGR) and mean net assimilation rate (NAR) values. However, during years four through five, RGR and NAR were significantly lower in the LWA treatment than in the HWA treatment. The reduction in herbaceous weed interference appeared to reduce mean leaf area ratio (LAR) throughout the study period.
Several trends in this data set suggest that growth analysis parameters may be confounded with size. The largest ideotype generally exhibited the smallest RGR, and RGR declined as trees increased in biomass. To remove the potential confounding of size, the basis of comparison was changed from trees of equal age to trees of equal biomass (total aboveground dry weight at the beginning of each growing season). This method resulted in a different interpretation of the results. For a given biomass, trees in the LWA treatment had greater RGR and LAR than those in the HWA treatment throughout the study period. Growth of seedling ideotypes within a given weed abundance treatment all fell along a single curve, suggesting that there was no apparent interaction between initial seedling diameter and herbaceous weed control.
After the trees reached six kg biomass, the direct benefits from reduced herbaceous interference had apparently ceased. Initially, large differences in NAR were observed between treatments, but these differences diminished as trees approached 5 kg. In contrast, differences in LAR were initially small but increased as tree biomass increased. As trees increased in biomass, the partitioning of carbon into leaf area seems to be more responsible for the productivity gains associated with weed control. For. Sci. 37(2): 655-668.
Allozyme and Leaf Morphological Variation of Eastern Cottonwood at the Northern Limits of Its Range in Ontario
Authors: Rajora O. P. , Zsuffa L. , Dancik B. P. 
Published: April 2024

Abstract
Allozyme variation of 84 trees of eastern cottonwood (Populus deltoides Bartr. ex. Marsh. var. deltoides) from 9 populations in Ontario was studied at 33 loci coding for 11 enzyme systems in root tips. Morphological variation of 7 leaf characters was studied for 57 trees. On average, 42.4% of the loci per population was polymorphic, the number of alleles per locus was 1.7, and the observed heterozygosity was 0.063. The overall mean for genetic distances among populations was 0.007. Principal component analysis (PCA) of allozyme data separated the populations into five groups with a slight separation of eastern and western populations. Leaf characters showed significant variation among (P ≤ 0.003) and with one exception within (P ≤ 0.027) populations. Vein numbers showed significant correlation with longitude (r = 0.81, P &lt; 0.009) and latitude (r = -0.69, P &lt; 0.05). None of the other leaf characters was related to latitude and longitude. PCA of leaf characters separated the Long Point population from the others. Significant (P &lt; 0.01) Mahalanobis distances for leaf characters were observed among populations. There was no concordance between the patterns of variation and differentiation based on allozymes and morphological parameters. The results suggest moderate allozyme and high leaf morphological variation in eastern cottonwood in Ontario. For. Sci. 37(2):688-702.
Using a Parallel Distributed Processing System to Model Individual Tree Mortality
Authors: Guan Biing T. , Gertner George 
Published: April 2024

Abstract
Parallel distributed processing (PDP, also known as artificial neural network) was introduced as an alternative for modeling regular noncatastrophic individual tree mortality. A two hidden-layered PDP system was created using back-propagation as the learning procedure and the sigmoid function as the transfer function. An empirical data set was used to test the performance of the system. Using the performance of a logistic regression as a benchmark, the new system had a better fit to the data than that of the logistic regression. It was also found that, though the system was not instructed to fit the data with logistic curves, the response surface of the model closely followed a logistic response surface. This finding suggests that, based on the goodness-of-fit measure employed, the best function to model individual tree mortality may indeed be the logistic function. A PDP system can be regarded as a procedure which attacks the problems of parameter estimation and model selection simultaneously. Topics regarding the potential use of a PDP system as an alternative to modeling individual tree mortality were also discussed. For. Sci. 37(3):871-885.
A Self-Contained Freezing Chamber for Tree Ecophysiological Studies in the Field
Authors: Dang Q. L. , Lieffers V. J. , Rothwell R. L. 
Published: April 2024

Abstract
A self-contained freezing chamber was constructed for use in tree ecophysiological studies in the field. The chamber has two layers, an outer layer of polystyrene board to provide both physical support and insulation, and an inner chamber of plastic to protect the twig and foliage from mechanical damage from the packs of freezing medium. The freezing medium is a NaCl:ice mixture which can provide chamber temperatures as low as -20.3°C. The mean temperature at seven locations within the chamber was -4.1°C with a standard deviation of ±0.3°C when a NaCl:ice mixture of 16(gm):1.65(l) was used. In field trials, it took two people about 3 minutes to set up the apparatus on a twig. The technique was found to be both practical and economical for field freezing experiments, especially in handling large sample sizes. For. Sci. 37(3):924-930.
Pass-Through of Exchange Rates on Prices of Forest Product Exports from the United States to Europe and Japan
Authors: Uusivuori Jussi , Buongiorno Joseph 
Published: April 2024

Abstract
Western Europe and Japan are major importers of forest products from the United States. Foreign exchange policies can influence the volume of trade mostly to the extent that devaluations or appreciations of the dollar are passed through to importers in the form of lower or higher prices in their currency. This paper reports measures of the pass-through for 6 European countries and Japan, for 11 commodities. The pass-through was obtained from a bivariate time-series model of export price and exchange rate. The data were from January 1978 to December 1988, a period of wide fluctuations in the value of the dollar. The results showed that the pass-through was often incomplete. In addition, the pass-through was asymmetric: appreciations of the dollar tended to increase foreign prices more than devaluations decreased them. Together the two findings suggest, first that dollar devaluations might not be effective in increasing exports of forest products, and second that global forest product markets are susceptible to inflation spread by currency realignments. The pass-through varied considerably by region, commodity, and over time: while the short-term pass-through could be complete, the effect could decay to a small fraction of the initial value, or disappear completely within 1 year. This result is consistent with previous findings of weak or inexistent effects of exchange rate changes on quantities traded. For. Sci. 37(3):931-948.
Tree-Ring Growth of Interior Douglas-Fir After One Year's Defoliation by Douglas-Fir Tussock Moth
Authors: Alfaro René I. , Shepherd Roy F. 
Published: April 2024

Abstract
Reductions in ring width of Douglas-fir, Pseudotsuga menziesii [Mirb.] Franco, trees defoliated for 1 year by the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), are reported. Trees were treated with a nuclear polyhedrosis virus, but the resultant epizootic which killed larvae and reduced defoliation took several weeks to develop and trees sustained varying degrees of damage. No negative effects of defoliation were noted in the year when feeding took place; on the contrary, a growth stimulation occurred. Defoliation levels above 50% resulted in growth reduction for 2 years following defoliation relative to nondefoliated trees. The implications of these growth changes for cost/benefit analysis of control options are discussed. For. Sci. 37(3):959-964.
Timber Supply and Life Cycle Harvest of Nonindustrial Private Forest Owners: An Empirical Analysis of the Finnish Case
Authors: Kuuluvainen Jari , Salo Jorma 
Published: April 2024

Abstract
The timber supply and life cycle harvest of nonindustrial private forest owners is studied. Given a perfect capital market, optimal harvesting decisions depend on timber prices, the interest rate, and the merchantable timber stock. Under effective credit rationing, timber supply and the life cycle harvest become dependent on forest owners' preferences, i.e., timber supply and consumption decisions must be made simultaneously. Thus, the effect of the price of timber on short-term supply becomes ambiguous, and the interest rate only has a negative income effect. Further, because the harvest and consumption are decided simultaneously, supply is also affected by owner characteristics. The optimal life cycle harvest rate need not be constant, and the age of the owner is a relevant explanatory variable. The timber supply function is estimated using Finnish micro data from 1982 to 1985, and the Tobit model. The hypothesis of an imperfect capital market cannot be rejected as the owner characteristics, including the owner's age, have highly significant coefficients, although the estimated coefficient of the interest rate is positive. The positive effect of the interest rate may be due to the fact that the loans of the credit-rationed forest owners in the sample are relatively small, and the positive effect of the nonrationed forest owners dominates. However, the effects of other capital (or, e.g., amenities) market imperfections cannot be ruled out. For. Sci. 37(4):1011-1029.
The Effect of Forest Productivity Taxes on Timber Stand Investment and Rotation Length
Authors: Amacher Gregory S. , Brazee Richard J. , Thomson Thomas A. 
Published: April 2024

Abstract
The qualitative and quantitative effects of productivity taxes are modeled. Previous analyses are extended in three directions. First, we correctly derive the qualitative effects of the forest increment tax on initial stand investment and rotation length. Second, we incorporate the harvest income tax into the Faustmann model, derive the qualitative effects of the harvest income tax on initial stand investment and rotation length. The qualitative effects from imposing productivity taxes on rotation length and initial stand investment cannot be predicted a priori. Whether rotation length and initial stand investment increase or decrease depends on whether rotation length and initial stand investment are complementary or competitive inputs in the stumpage volume function. Third, we simulate the effects of productivity taxes for Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and loblolly pine (Pinus taeda) stumpage volume functions. Two general conclusions emerge from the simulations. First, similar to the qualitative effects, the quantitative impacts from imposing productivity taxes on rotation length and initial stand investment are impossible to predict a priori. Rotation length and initial stand investment may increase or decrease depending on the form of the volume function, the tax rate, and the interest rate. Second, the impacts of imposing productivity taxes on rotation length and initial stand investment range from quite modest to very large. For. Sci. 37(4):1099-1118.
Growth Patterns of Deerbrush and Snowbrush as Functions of Age and Shrub Vigor
Authors: Minore Don , Means Joseph E. , Cunningham Patrick G. , Weatherly Howard G. 
Published: April 2024

Abstract
To describe the growth of deerbrush (Ceanothus integerrimus Hook & Arn) and snowbrush (C. velutinus var. velutinus Dougl. ex Hook.) by age and shrub vigor, stem-analysis techniques were applied to 61 open-grown shrubs of each species in southwestern Oregon. Present crown dimensions were measured, and past stem lengths for each year of growth were determined by dissecting the longest stem. Models were fit to describe stem length as a function of plant age and stem length at age 10 (L10) for each species. Shrub height and crown area were then related to length of the longest stem, and curves were constructed to illustrate crown development by age and L10. The results can be used to estimate the growing space that will be occupied by open-grown shrubs of either species at any time from ages 4 through 20. For. Sci. 37(4):1140-1149.
Effects of Seed Weight and Rate of Emergence on Early Growth of Open-Pollinated Douglas-Fir Families
Authors: St. Clair J. B. , Adams W. T. 
Published: April 2024

Abstract
Seed weight, time of emergence, and three measures of seedling size were recorded for 39 open-pollinated Douglas-fir (Pseudotsuga menziesii vat. menziesii [Mirb.] Franco) families in order to assess family variation in seed weight and emergence, and the influence of these seed traits on early growth. Families were planted both as ungerminated seed and as recent germinants to test whether using germinants minimized seed effects on early growth. To evaluate the effect of competition on the relationships of seed weight and rate of emergence to seedling size, individuals of families were planted in mixed-family blocks at close spacing, in single (pure) family blocks at close spacing, and at a wide, noncompetitive spacing. Families differed significantly in seed weight, total percent emergence, and rate of emergence. Nevertheless, correlations of seed weight to rate of emergence, and seed weight and rate of emergence to seedling size were not strong. Using germinants was ineffective in diminishing seed effects, and interfamily competition had only a minor influence on magnifying seed effects. For. Sci. 37(4):987-997.