bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binary-Search SPOC: An Optimal Control Theory Version of ECHO
Authors: Lyon Kenneth S. , Sedjo Roger A. 
Published: April 2024

Abstract
Two models for identifying the optimal harvest of old-growth forests—the supply potential optimal control model, SPOC, and the economic harvest optimization model, ECHO—are compared theoretically and numerically. Walker's ECHO restart procedure to solve convergence problems is examined and found to be theoretically sound. The primary difference between the models is that SPOC incorporates the effects of future rotations while ECHO does not. A new algorithm, binary-search SPOC, is identified which incorporates the effects of future rotations by including a difference equation for the shadow value of these rotations. This algorithm is the solution to a discrete time optimal control problem.
The numerical analysis of Walker's original problem revealed that the ECHO solution was very close in the early years when the implicit land rental was low and rising, but generated the wrong long-run equilibrium. Forest Sci. 32:576-584.
Regeneration of Fraser Fir at Mt. Mitchell, North Carolina, After Depredations by the Balsam Woolly Adelgid
Authors: Witter John A. , Ragenovich Iral R. 
Published: April 2024

Abstract
The long-term ecological consequences of balsam woolly adelgid (Adelges piceae(Ratzeburg)) damage to Fraser fir (Abies fraseri (Pursh) Poir.) are considered. Study areas were established and vegetation sampled during 1966 in western North Carolina near and on Mt. Mitchell in each of three forest types: fir, spruce-fir, and spruce-fir-hardwood. Study areas were resampled in 1978. In 1966, mortality caused by the balsam woolly adelgid on Fraser fir stems over 244 cm tall averaged 82, 98, and 95 percent in the fir, spruce-fir, and spruce-fir-hardwood types, respectively. The average number of live Fraser fir seedlings per hectare for all study areas in 1966 and 1978 were 25,809 and 14,026, respectively. The height class distribution of Fraser fir seedlings changed dramatically with approximately 1 percent of the trees over 61-cm tall in 1966, and 75 percent over 61-cm tall in 1978. The fir, spruce-fir, and spruce-fir-hardwood types are well-stocked with Fraser fir regeneration and fir should be an important species in all three forest types in the future. Forest Sci. 32:585-594.
Cortical Monoterpene Variation Among Slash Pine Ramets by Season, Aspect, Crown Position, and Bud Vigor
Authors: Kossuth Susan V. , Muse H. David 
Published: April 2024

Abstract
Cortical monoterpene composition from all buds of four grafted ramets, 10-12 years old, from one clone, was analysed to determine the best location and time of year to sample to obtain repeatable values in determining individual tree phenotypes. A total of 1,415 buds were analysed representing various sampling positions in the crown during the 4 seasons of the year. The content of α-pinene, β-pinene, and β-phellandrene in individual buds ranged from 19.0 to 47.7, 18.2 to 59.4, and 4.5 to 31.9 percent, respectively. Statistically significant differences were found among the sampling units for the three monoterpenes for crown position, bud vigor, and season of year; however, these differences were relatively small and each grouping gave essentially the same tree phenotype. No differences were found between aspects. In a separate analysis it was determined that sampling five buds from the lower crown would give a monoterpene phenotype within 5 percent of the bud population mean for all three major monoterpenes with a 95 percent confidence limit. Bud diameter and length of flush increased progressively from the lower to upper crown and low- to high-vigor buds. Flush lengths and bud diameters were the same for both aspects of the trees. Forest Sci. 32:605-613.
Basal Area Prediction and Projection Equations for Pine Plantations
Authors: Pienaar Leon V. , Shiver Barry D. 
Published: April 2024

Abstract
Generalized stand-level basal area prediction and projection equations for unthinned as well as thinned plantations are proposed. Appropriate slash pine data sets from long-term spacing and thinning studies, representing a wide range in site quality, planting densities, and thinning intensities, are used to demonstrate the utility of these equations. Examples of the use of these equations are given to illustrate the importance of past thinning history for the prediction and projection of basal area in plantations of the same age, trees per acre, and average dominant height. Forest Sci. 32:626-633.
Wildfire Impacts on the Present Net Value of Timber Stands: Illustrations in the Northern Rocky Mountains
Authors: Mills Thomas J. , Flowers Patrick J. 
Published: April 2024

Abstract
Change in the present net value of the timber resource as a result of a wildfire is a primary input into the determination of economically efficient fire management programs. A procedure was developed to estimate the change in present net value of timber outputs, termed here "net value change." The timber net value change was then estimated for a large number of hypothetical fire situations in the northern Rocky Mountains to determine how fire situation characteristics affect net value change. Each hypothetical fire situation was described by eight variables: timber management emphasis or objective, cover type, stand size, productivity class, slope class, roading, percent mortality, and fire size. The mean net value change for poletimber stands was greater ($289 per acre burned) than the net value change for seedling and sapling ($148 per acre burned) or sawtimber stands ($133 per acre burned). The timber net value change varied considerably about these means, however, depending on the value of the variables that describe the fire situation. Forest Sci. 32:707-724.
Leaf Area Prediction Equations for Young Southeastern Hardwood Stems
Authors: Bacon Catherine G. , Zedaker Shepard M. 
Published: April 2024

Abstract
Sixteen common hardwood species were sampled in young pine plantations of the Virginia Piedmont to develop predictive equations for leaf area from stem cross-sectional area. Leaf area (total surface area) was found to be linearly related to stem cross-sectional area for each species, with coefficients of determination (R²) ranging from 0.87 to 0.98. Slope coefficients ranged from 0.336 to 0.833 m²/cm² and were significantly different for all but two of the species. A comparison within species showed no significant difference in slopes between single stems and multistemmed sprouts. Forest Sci. 32:818-821.
Critical Height Sampling and Volumes by Cylindrical Shells
Authors: Lynch Thomas B. 
Published: April 2024

Abstract
The approach to unbiasedness used by McTague and Bailey (1985) is extended to prove that the critical height sampling stand volume estimator is unbiased for any tree taper. This is done by using the method of cylindrical shells to calculate individual tree volumes as solids of rotation. The bias that occurs when attempting to estimate total stand volume by sighting sample trees at dbh rather than stump diameter is discussed. Adjustments for bias are proposed when taper functions other than those used by McTague and Bailey (1985) are applicable, though the bias would be negligible in most practical applications. Forest Sci. 32:829-834.
In Vitro Digestibility of Juniperus osteosperma (Torr.) Little from 17 Utah Sites
Authors: Bunderson E. D. , Welch Bruce L. , Weber D. J. 
Published: April 2024

Abstract
Fall in vitro digestibility was determined on forage collected from Utah juniper (Juniperus osteosperma) trees from 17 sites throughout the pinyon-juniper zone of Utah. On an individual tree basis, the in vitro digestibility ranged from 33.4 to 53.1 percent of dry matter. Forage from mature and juvenile trees was significantly more digested than forage from seedlings. Forage collected from some sites was sigificantly more digested than from other sites. Digestibility across sites ranged from 39.2 to 47.9 percent of dry matter digested. Utah juniper was more digestible than some winter range plants such as antelope bitterbrush (Purshia tridentata), Gambel oak (Quercus gambelii), chokecherry (Prunus virginiana), and less than others such as big sagebrush (Artemisia tridentata) and black sagebrush (Artemisia nova). It is an average to slightly above average winter food for deer. Genetic improvement or selection for superior nutritive cultivars may be possible. Forest Sci. 32:834-840.
A Multiattribute Utility Model for Incorporating Risk in Fire Management Planning
Authors: Teeter Lawrence D. , Dyer A. Allen 
Published: April 2024

Abstract
The potential variability of investment returns often perplexes the investment selection process. On national forests, the relative efficiency of alternative fire management strategies is investigated using a modification of traditional cost plus loss methods. Current procedures do not indicate potential variability in the performance of these alternatives, however. A multiattribute utility model is presented as the appropriate framework for evaluating alternatives when decision-makers are concerned with the risk and efficiency implications of selecting a particular strategy. Among fire management planners, the term risk usually relates a perception of the variability of potential damages. A risk measure is defined and an index is created to indicate the performance of each fire management strategy relative to the potential performance of a standard established as a benchmark. Utility functions for the risk attribute were assessed using hypothetical lotteries where the value (utility) of risk was a function of its deviation from a risk benchmark. Two-attribute utility functions indicated surveyed respondents' preferences for attaining risk and efficiency related objectives. Analysis yielded two conclusions: (1) that fire management planners are not risk-averse, and (2) including risk as an attribute of the decision problem can significantly influence investment selection. Forest Sci. 32:1032-1048.
Energy Yield of Black Locust Biomass Fuel
Authors: Stringer Jeffrey W. , Carpenter Stanley B. 
Published: April 2024

Abstract
Detailed analysis of 2- to 10-year-old black locust (Robinia pseudoacacia L.) biomass components provided an accurate energy content and energy yield determination as well as an index defining a relative ceiling on the delivered cost for black locust biomass in comparison with other fuels such as coal and forest residues. Total energy content of individual biomass components ranged from 20.97 x 106 J kg-1 for leaf tissue to 19.23 x 106 J kg-1 for current years' growth. Annual total energy yields ranged from 33.75 to 76.79 x 109 J ha-1 yr-1 for 3- and 9-year-old stands, respectively. Nine-year-old stands also exhibited the highest annual net whole-tree and woody biomass (whole-tree less foliage) energy yields of 32.71 and 30.73 x 109 J ha-1 yr-1. The net annual energy yields were consistently greater for whole-tree biomass compared with woody biomass due to the foliage included in the whole-tree biomass. The relative cost indices maintained a high degree of variability between comparison fuels. Bituminous coal and forest residues were lowest with an overall mean cost index for woody biomass of $13.28 mt-1 and $13.72 mt-1, respectively. Woody biomass maintained a greater relative index than whole-tree biomass over all age classes due to its inherently higher conversion efficiency. Forest Sci. 32:1049-1057.
Rectifying Radii on Off-Center Increment Cores
Authors: Liu C. J. 
Published: April 2024

Abstract
A geometric model for rectifying radii on an off-center core has been developed and found to be sufficiently accurate and consistent, with an average error of 1/120. The estimation procedure described should prove useful to foresters, biologists, dendrochronologists, archaeologists, and other researchers who use tree-ring data in their scientific investigations. Forest Sci. 32:1058-1061.
Estimation of Log Volume by Importance Sampling
Authors: Furnival George M. , Valentine Harry T. , Gregoire Timothy G. 
Published: April 2024

Abstract
Importance sampling is proposed as a technique for estimating log volume that eliminates the bias of conventional methods arising from irregular log taper. In a trial of the technique, the average relative sampling error for individual logs, based on a measurement of one cross-section per log, was 5.2%. To estimate an aggregate volume, a two-stage sampling procedure is suggested in which importance sampling constitutes the second stage. Optimal sampling strategy is discussed briefly. Forest Sci. 32:1073-1078.
Effects of Precommercial Thinning on Understory Vegetation and Deer Habitat Utilization on Big Level Island in Southeast Alaska
Authors: Doerr Joseph G. , Sandburg Nancy H. 
Published: April 2024

Abstract
Available evidence suggests that many wildlife species are affected by the low understory production that characterizes closed-canopy, even-aged stands in southeastern Alaska (Wallmo and Schoen 1980; Alaback 1982; Van Horne 1981, 1982; Kessler and Kogut 1985). Precommercial thinning has been suggested as a method of prolonging or maintaining understory as young clearcuts develop into pole stands (United States Department of Agriculture 1986). Information on the effects of thinning on understory growth and the response of wildlife to thinning in southeastern Alaska is lacking. This study reports on the effects of precommercial thinning on understory development and utilization by Sitka black-tailed deer (Odocoileus hemionus sitkensis) on a small island 18 years after treatment. Forest Sci. 32:1092-1095.
The Influence of Gypsy Moth on the Composition and Nutrient Content of Litter Fall in a Pennsylvania Oak Forest
Authors: Grace J. R. 
Published: April 2024

Abstract
Litter fall was studied on gypsy moth (Lymantria dispar (L.))-defoliated plots and undefoliated plots in a Pennsylvania oak forest. Litter, collected throughout the year, was separated by plant and insect component and analyzed for dry weight and five major nutrients. Total biomass of litter falling on the defoliated and the undefoliated areas was not significantly different. Within the undefoliated plots, 90% of the litter was deposited during the autumn, and tree leaves were the major litter component. Major litter components within the defoliated plots included insect frass, leaf fragments, and tree leaves; 56% of the litter was deposited during the growing season. The nutrient content of litter totaled 73.1 kg/ha on the undefoliated plots, and tree leaves contributed 85% of all nutrients. The nutrient content of litter on the defoliated plots amounted to 94.6 kg/ha; leaf fragments, insect frass, and tree leaves contributed 34, 25, and 29% of all nutrients. Gypsy moth defoliation caused a statistically significant increase in the quantities of N, P, and K and a significant decrease in the quantity of Ca contained in litter fall. These differences are attributed to the gypsy moth altering the composition and seasonal distribution of litter fall. The significance of this nutrient shift is viewed as a further detriment to the health and vigor of host trees. Forest Sci. 32:855-870.
An Approach for Optimizing Residual Diameter Class Distributions When Thinning Even-Aged Stands
Authors: Roise J. P. 
Published: April 2024

Abstract
The determination of optimal residual diameter class distributions along with optimal timing of thinning and harvest is formulated as an unconstrained nonlinear program. Two structural characteristics of the problem are noted. A nonlinear programming algorithm is modified to take advantage of these characteristics. An example is used to illustrate the technique. The total number of variables within the formulation can be reduced to a small fraction of active variables. The ratio between active and total variables is approximately 0.3, or an approximate 70% reduction in problem size is experienced. The same amount of reduction would be expected in any similar formulation. Forest Sci 32:871-881.
Leaf-to-Twig Transfer Conserves Nitrogen and Phosphorus in Nutrient Poor and Enriched Cypress Swamps
Authors: Dierberg Forest E. , Straub Peter A. , Hendry Charles D. 
Published: April 2024

Abstract
The external and internal N and P cycling of cypress trees in natural and sewage-enriched cypress swamps in north central Florida was investigated. Based on monthly changes in foliar and twig nutrient pools sampled for a year, concentrations of N and P in leaves decreased over the growing season. Nitrogen and phosphorus concentrations in the twigs increased immediately prior to leaf abscission. In both swamps, nutrients were available for early-season leaf growth the next spring. There were significant differences between the natural and sewage-enriched swamps in N concentrations in twigs, N and P concentrations in foliage, and changes in P concentrations in foliage; seasonal changes in N and P concentrations in twigs and N in foliage were not different between swamps. Nutrient increases in leaves were very rapid during early spring, but by May there was a slow decrease of N and P, probably from being retranslocated back to the twigs. Concentrations of total organic N in throughfall were significantly enriched in the natural swamp relative to precipitation, while ammonium concentrations in throughfall were signficantly lower than in precipitation. Leaf fall plus foliar leaching, which were 1.25 kg P ha-1 and 20.3 kg N ha-1 in the natural swamp and 6.1 kg P ha-1 and 51.6 kg N ha-1 in the sewage amended swamp, returned 87 and 66% of the P and N, respectively, taken up by the trees each year in both swamps, indicating that more nitrogen than phosphorus on a percentage basis was permanently added to the above-water cypress each year. Adding sewage increased the importance of root uptake: 7.2 kg P ha-1 and 78.2 kg N ha-1 accounted for 34 and 48% of the uptake required for net primary production in the swamp receiving sewage effluent while in the natural swamp only 17% of the P (1.4 kg P ha-1) and 31% of the N (30.8 kg N ha-1) required for net production was supplied by root uptake. The internal biochemical cycle of leaf-to-twig transfer of nutrients (7.0 kg P ha-1 and 68.1 kg N ha-1 in the natural dome; 13.8 kg P ha-1 and 83.6 kg N ha-1 in the sewage-enriched swamp) was more important in conserving nutrients than leaf fall, leaf leaching, and root uptake, suggesting that the major nutrient conservation strategy in cypress swamps is redistribution of nutrients from abscissing leaves to more permanent tissue before leaf senescence. Forest Sci 32:900-913.
Budbreak for Twenty-Three Upland Hardwoods Compared Under Forest Canopies and in Recent Clearcuts
Authors: McGee Charles E. 
Published: April 2024

Abstract
Patterns of budbreak and leaf development were monitored on 23 upland hardwoods on the Cumberland Plateau of middle Tennessee. These patterns varied by species, topographical location, and the presence or absence of a forest canopy. Most species began budbreak earlier in coves on the Plateau escarpment than on the Plateau top. Most tolerant species began budbreak earlier under forest canopies than in open clearcuts. Six species of Quercus consistently had budbreak and leaf appearance earlier under canopies than in clearcuts. Apparently, the propensity of some species to initiate growth early under a canopy increases their shade tolerance by allowing some leaf development before crown closure. These patterns are not necessarily beneficial once the canopy is removed.
Time requirements for completion of the budbreak process varied substantially within species. Individual Cornus florida, Quercus alba, and Carya sp. began and completed budbreak within 2 days. Other individuals of the same species and size required up to 25 days to complete budbreak. Forest Sci. 32:924-935.
Role of Company Sales in Funding Research and Development by Major U.S. Paper Companies
Authors: Bullard Steven H. , Straka Thomas J. 
Published: April 2024

Abstract
Forestry research is conducted by state and federal agencies and by many private firms. Studies of research productivity and efficiency are increasingly common in forestry, due to the greater scale of research activity, and increasing competition for both public and private funds. Research evaluations rely on accurate measures of research inputs and outputs. This article presents an equation to predict research inputs for five major firms in the U.S. pulp and paper industry. Pulp and paper research by major U.S. companies is very closely related to corporate sales each year. The relationship empirically supports important assumptions that have been used in studies evaluating aggregate returns to research. Forest Sci. 32:936-943.
Factors Limiting Denitrification in Soils from Mature and Disturbed Southeastern Hardwood Forests
Authors: Davidson Eric A. , Swank Wayne T. 
Published: April 2024

Abstract
The relative importance of O2, NO3-, organic carbon, and acidity on denitrification was studied in a full 26 factorial experiment. Soils were collected from two forested watersheds (WS) (disturbed and reference) and at two slope positions (stream-bank and hillside). Combinations of four incubation treatments (with and without H2O flooding, NO3- amendment, glucose amendment, and at ~pH 5 or ~pH 6) were applied in a full factorial design. An ANOVA of N2O production during 24-hr aerobic incubations under 10 kPa acetylene revealed that all main effects were significant. Flooding with H2O increased N2O production by three orders of magnitude in disturbed WS soils exhibiting high ambient NO3-. Both flooding and NO3- amendment were necessary to increase N2O production in reference WS soils exhibiting low ambient NO3-. Glucose amendment increased N2O production in the mineral soil sampled at 6-15 cm depth more than in the 0-6 cm sample. Carbon limitation is probably unimportant for denitrification in surface horizons at Coweeta, but C-limitation occurs with increasing soil depth. Although acid treatment had a minor inhibitory effect on denitrification rates, acid forest soils apparently support denitfifier populations capable of appreciable NO3- reduction. For. Sci. 33(1):135-144.
Frequency Sampling to Predict Densities in Sparse Populations of the Douglas-Fir Tussock Moth
Authors: Mason Richard R. 
Published: April 2024

Abstract
Density in the middle crown of the tree is a widely used index of abundance of the Douglas-fir tussock moth (Orgyia pseudotsugata [McDunnough]). Midcrown density is usually estimated by the destructive sampling of branches in the middle crown, but in sparse populations it can also be predicted by observing the frequency of occurrence of larvae or pupae on lower branches. Predictions are made from a prior calibration between the proportion of infested samples in lower branches and midcrown density. Two models for calibration were developed: an empirical relation based on regression analyses of population data, and a theoretical relation derived from the frequency distribution of individuals in a Poisson series and the vertical distribution of insects in the tree. The models produced almost identical results in predicting midcrown densities from estimated proportion values. The theoretical model is recommended because of its versatility for different-aged larvae and generality over a wider range of low densities. For. Sci. 33(1): 145-156.
An Analysis of Regional Factor Demand in the U.S. Lumber Industry
Authors: Abt Robert C. 
Published: April 2024

Abstract
A restricted cost function with labor and roundwood as variable inputs and capital as quasi-fixed is estimated for three lumber producing regions. Significant regional differences are found. Cost function estimates are used to decompose trends in factor demand from 1963 to 1978. Stable trends in input use are found to be due to offsetting price and technology trends rather than fixed production relationships. For. Sci. 33(1):164-173.