bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field and Laboratory Investigations of Seed Dormancy in Red Maple (Acer Rubrum L.) from the North Carolina Piedmont
Authors: Peroni Patricia A. 
Published: April 2024

Abstract
Field and laboratory investigations were conducted using seeds collected from red maple populations located in the North Carolina piedmont to determine: (1) the percentage of red maple seedling establishment each spring that can be attributed to dormant seeds, (2) the percentage of seeds that display dormancy upon dispersal, (3) the effect of short periods of dry conditions at 20-22°C on dormancy and seed viability. The greenhouse results indicated that red maple from these populations display moderate levels of seed dormancy (14%) when provided with conditions conducive to germination immediately upon dispersal. However, in the field, the majority of red maple seedlings that established in both 1988 (59%) and 1989 (nearly 100%) emerged from dormant seeds. The dry delay treatment led to significant increases in seed dormancy and decreases in seed viability, which suggest that some seed dormancy in red maple may be acquired rather than innate. Maternal families showed significant variation in levels of seed dormancy, and the effects of the dry delay treatment on seed viability also varied among maternal families. For. Sci. 41(2):378-386.
Modeling Stand Level Growth and Yield Response to Silvicultural Treatments
Authors: Pienaar L. V. , Rheney J. W. 
Published: April 2024

Abstract
As plantation growth and yield research lead to new, more intensive, and site-specific silvicultural prescriptions, there is a perpetual need to adjust existing yield prediction models to reflect the response to these practices. A height growth model that includes a treatment response term to accommodate different expected response patterns is presented. This model is shown to provide an accurate description of the observed average dominant height growth response of slash pine plantations to several silvicultural treatments, relative to standard practice. An existing per-acre basal area prediction model for unthinned plantations that includes average dominant height as a predictor variable, in addition to age and trees per acre, also required an adjustment term to adequately reflect treatment effects on stand basal area growth. No such adjustment appeared to be necessary, to account for different silvicultural practices, to an existing stand level volume prediction model that includes both average dominant height and basal area per acre as predictor variables, in addition to age and trees per acre. For. Sci. 41(3):629-638.
Estimating the Cost of Fuels Treatment
Authors: Rideout Douglas B. , Omi Philip N. 
Published: April 2024

Abstract
We develop a potentially generalizable cost estimation procedure for fuels treatment using the National Park Service (NPS) nationwide database. The NPS database includes records on the projected cost of fuel treatment projects. These records are kept separately for traditional hazard fuel reduction projects and for resource management projects. Resource management projects are intended to implement objectives associated with the enhancement or restoration of ecosystems. Hence, we used resource management projects as a proxy for activities which might be pursued by public land managers in the name of ecosystem management. Our cost estimation procedure focuses on a constant elasticity of declining unit cost with increases in scale. Using multiple regression techniques, we test and confirm the hypotheses that the constant elasticity estimate can be applied to treatments intended to reduce fuel hazards or to treatments preferred for ecosystem management objectives. We also tested and confirm the hypothesis that ecosystem management cost estimates are more uncertain and therefore less precise than those made for the more traditional fuels hazard reduction treatments. We infer that the constant elasticity cost expression for fuels treatment is generalizable because it was found independent of treatment scale, management objective, fuel type, or other physical and economic attributes common to fuels treatments. We identify additional attributes of fuels treatment, including location, fuel type and treatment method that significantly affect cost estimates. For. Sci. 41(4):664-674.
Hurricanes and the Economics of Loblolly Pine Plantations
Authors: Haight Robert G. , Smith William D. , Straka Thomas J. 
Published: April 2024

Abstract
Following a damaging storm, managers of small forest tracts often want to know when to harvest and reforest to maximize financial return. The assessment of financial return is complicated by the need to project the product value of damaged trees and to account for the risk of another damaging storm. Methods are demonstrated for handling both these complications. The effects of stem sweep on product value is projected by incorporating a sweep distribution into a simulator for stand growth and computing stumpage value using a residual value approach in which trees are optimally allocated to product classes based on their stem dimensions. A single-rotation formula for a stand's expected present value (EPV) is derived assuming age-dependent damage risk and salvage proportion. Using information about damage following Hurricane Hugo in South Carolina and risks of storm damage in coastal areas of the southeastern United States, the stand-level economic impacts of several variables are estimated. Results show that age-dependent damage risk and stocking reduction caused by tree mortality have the greatest impact on the relationship between EPV and rotation age. The effects of salvage proportion and stand damage in the form of stem sweep are relatively small. These results highlight the variables that need careful specification in any assessment of the financial return of a damaged stand. For. Sci. 41(4):675-688.
Correlated Observer Errors and their Effects on Survey Estimates of Needle-Leaf Loss
Authors: Gertner George , Köhl Michael 
Published: April 2024

Abstract
In Europe, crown transparency is one of the most important variables assessed for monitoring forest conditions. Though there are very strict international guidelines and intensive training programs for the evaluation of needle-leaf loss, there still exists a subjective component in the evaluation. This subjective component in the observation process can lead to a nonsampling error that can greatly reduce the precision of estimates of average needle-leaf loss. In this paper, methods for quantifying the potential loss in precision are presented and applied to data from the Swiss National Forest Health Monitoring Program. For. Sci. 41(4):758-776.
Point Sampling with Disjunct Support Near Population Boundaries
Authors: Moisen Gretchen G. , Stage Albert R. , Born J. David 
Published: April 2024

Abstract
In inventories that guide land management, point sampling is heavily used to estimate land area occupied by a population, area by condition class, population mean density, and totals of population attributes. Often, for reasons of efficiency or interpretation, the attributes of the principal sample point are described by aggregating information over a group of satellite points arrayed in a geometric pattern around the principal point. This group of data sampling points forms what is called the "support" for the principal point. Problems arise when the principal point is close enough to a population (or subpopulation) boundary for some of the support points to fall outside that boundary. Ad hoc solutions to this problem that involve replacing some or all of the points in the group may introduce bias into the inventory estimates. Unfortunately, procedures that do not replace points introduce bias into estimates of attributes that can be defined only with respect to the configuration and volume of the support. Examples of such attributes include distribution of area by classes of tree density, stocking, species composition, stand structure, and the ecological frequency and constancy of a species. A rule has been developed for reshaping the pattern of support points that resolves the dilemma for single, straight boundaries. Simulations to evaluate the rule show that it produces a uniform density of points with respect to distance from the boundary while maintaining a compact region of support for the principal point. For. Sci. Monogr. 31:62-82.
Chance-Constrained Optimization with Spatially Autocorrelated Forest Yields
Authors: Hof John , Bevers Michael , Pickens James 
Published: April 2024

Abstract
This note investigates the implications of spatially autocorrelated yields on forest management optimization procedures and results. The problem is defined and analyzed conceptually, followed by a simple case example demonstration. It is concluded that spatial arrangements may be quite important in managing risk and uncertainty in forest ecosystems. For. Sci. 42(1):118-123.
Statistical Causation and National Forest Policy in Oregon
Authors: Burton Diana M. , Berck Peter 
Published: April 2024

Abstract
Granger causality tests are used to examine the relationships among macroeconomic variables, harvests, forestry sector employment, and national forest policy in Oregon. Statistical causation is found to run generally from macroeconomic variables to forestry employment, to harvests and to national forest policy. These findings raise questions about the validity of using national forest harvest policy to effect employment and community stability objectives. For. Sci. 42(1):86-92.
Testing a Mechanistic Model for Predicting Stand and Tree Growth
Authors: Korol R. L. , Milner K. S. , Running S. W. 
Published: April 2024

Abstract
Given the uncertainty of future climate regimes, it has become necessary to develop growth and yield models that can respond to potential changes in climate. TREE-BGC, a derivative of the physiological process model FOREST-BGC, was used to simulate the growth of 998 trees in unevenaged stands near Kamloops, B.C. Stand variables were derived from a tree list. The model used a disaggregation logic to allocate stand level estimates of carbon gain and respiration costs to individual trees. Increments in height and diameter were estimated so as to maintain their allometric relation, but scaled to produce an estimate of stem volume equivalent to the carbon allocated to the trees. Mortality was simulated when the maintenance respiration of the tree exceeded the carbon allocated to the tree. Plot level estimates of 20 yr basal area increment and volume increment were highly correlated with actual measurements (r² = 0.94 and 0.96, respectively; n = 24). The cumulative modeled diameter and height distributions were compared to measured distributions. The simulated cumulative diameter and height distributions were not significantly different from the actual cumulative diameter and height distributions for 23 of the 24 plots (α = 0.05). The model was found to have an accuracy of about 0.16 m² ha-1 yr-1 for basal area and 1.51 m³ ha-1 yr-1 for volume (α' = α" = 0.05), averaged over the 20 yr period. Long-term model behavior was influenced by stand density, basal area, and volumes. Stand mortality appeared to emulate the so-called self-thinning rule, and a maximum size-density relationship was found. For. Sci. 42(2):139-153.
The Influence of Environmental Conditions on Tree-Ring Series of Norway Spruce for Different Canopy and Vitality Classes
Authors: Van Den Brakel Jan A. , Visser Hans 
Published: April 2024

Abstract
A dendroecological study of Norway spruce trees was undertaken by Eckstein et al. (1989) as part of an interdisciplinary project investigating the influence of air pollution on tree growth in northern Germany. They analyzed individual trees stratified according to three different canopy classes and three different vitality classes, using response function analysis (Fritts 1976). Eckstein et al. conclude that there is a significant positive correlation between precipitation during the growing season and the tree-ring series, and that the observed forest decline is probably caused by a severe unknown stress factor (but clearly not a climate factor) during the mid-1950s. The use of response functions has the limitation of time invariance and the separated adjustment of trend and climate variables for the tree-ring series. In this article a model is applied for simultaneous adjustment of trend and explanatory variables for tree-ring chronologies. Time-dependent or stochastic response functions are obtained by writing these models in the so-called state-space form and analyzing them with the discrete Kalman filter. Consequences for chronology building are discussed. After analyzing the tree-ring chronologies of the Norway spruce by these more sophisticated methods, it is found that: 1. the stochastic response functions for precipitation during the growing season are principally constant over time and positive, 2. the stochastic response functions for the temperature in February and March are not constant and become significant after the mid-1950s for trees from the classes "not dominant-vital," "not dominant-moderately vital," "dominant-not vital," "moderately dominant-not vital," and "not dominant-not vital," 3. the influence of climate factors on tree-ring development is higher if the vitality and dominance of the trees is lower, 4. addition of an SO2 emission curve as explanatory variable, simultaneously with trend and climate variables for tree-ring chronologies, did not reveal a significant air pollution effect on tree-ring development. For. Sci. 42(2):206-219.
The Standing Skyline: A Maximum Log Load Solution Procedure
Authors: Brown Cameron , Sessions John 
Published: April 2024

Abstract
Many harvesting operations use a standing skyline cable system in steep topography or on fragile soils. We present an efficient algorithm for calculating the maximum log load which can be carried with a standing skyline system, suitable for analyzing situations where the logs are either fully suspended above the ground or partially suspended above the ground. For. Sci. 42(2):220-227.
Stand Characteristics Associated with Mountain Pine Beetle Infestations in Ponderosa Pine
Authors: Olsen W. K. , Schmid J. M. , Mata S. A. 
Published: April 2024

Abstract
Stand characteristics associated with mountain pine beetle (Dendroctonus ponderosae Hopkins), infestations within a 2.15 ac (0.87 ha) plot were analyzed to determine characteristics most strongly correlated with the infestations. Trees per acre, basal area, quadratic mean diameter, minimum diameter, and the range of diameters in MPB infested groups were significantly different from those in noninfested groups. Maximum diameter was not different between infested and noninfested groups. The results are discussed in regard to the mountain pine beetle-host relationship and stand management. For. Sci. 42(3):310-327.
A Stochastic Model for Tree Survival in Stands Affected by Annosum Root Disease
Authors: Preisler Haiganoush K. , Slaughter Garey W. 
Published: April 2024

Abstract
Mortality of trees surrounding pine stumps colonized by Heterobasidion annosum for about 35 years was monitored over a period of 20 yr in 53 eastside pine stands in northern California. The data were used to develop a stochastic model that quantifies effects of tree characteristics and spatial proximities on survival of trees within 12 m of a colonized stump. The model accommodates mortality data collected at irregular intervals. Variables with significant effects on tree survival included trees species, size, and distance of roots from the root of a previously dead tree. Results from stochastic models based on actual data are useful for detecting factors affecting tree survival and for evaluating assumptions of numerical (simulation) models, such as root disease computer models. For. Sci. 43(1):78-86.
Growth and Water Use of Red Spruce (Picea Rubens Sarg.) Exposed to Ozone and Simulated Acidic Precipitation for Four Growing Seasons
Authors: Laurence J. A. , Amundson R. G. , Kohut R. J. , Weinstein D. A. 
Published: April 2024

Abstract
Red spruce (Picea rubens Sarg.) saplings from a pristine site in Maine were transplanted in native soil to 360 liter pots and relocated to Ithaca, New York. After a 1 yr establishment period, 90 saplings were chosen for use, assigned to treatments, placed in large open-top chambers, and exposed to ozone (0.5 to 2.0 x ambient concentration) and simulated acidic precipitation (at pH 3.1, 4.1, or 5.1) for 3 or 4 consecutive growing seasons (total ozone exposures of about 165 ppm · hr to almost 570 ppm · hr). Forty-five trees were grown on weighing lysimeters and were used to develop whole-tree water-use budgets. After 3 yr of exposure, the 45 trees not grown on lysimeters were harvested, and the plant tissues were weighed. After the fourth growing season, the remaining 45 trees were harvested, and the weight of the plant tissues was determined. Significant effects of ozone or simulated acidic precipitation were not detected, with the exception of a trend for increased needle dry weight with increasing ozone and, in 1990 needles only, with decreasing pH. No effects were detected in total dry weight, aboveground dry weight, coarse or fine root weight, stem dry weight, or relative growth rate. No significant interactions of ozone and pH treatment were detected. Neither ozone nor pH treatment affected the rate of water use by red spruce saplings, even when they were subjected to a dry-down period resulting in drought stress. For. Sci. 43(3):355-361.
The Effects of Neighborhood Storage Size on Dynamic Programming Solutions
Authors: Pelkki Matthew H. 
Published: April 2024

Abstract
Forward recursive dynamic programming (DP) was used to investigate the sensitivity of two- and three-state dynamic programming networks to neighborhood storage. Two-state DP networks were formed using all pairwise combinations of four state variables (basal area, cubic foot volume, number of trees, and diameter) and various neighborhood intervals for each state variable. As state neighborhoods decreased in size, all solutions were converged on a single rotation scheme and objective function value. Large state neighborhoods with nonuniform future growth and value potentials result in suboptimal solutions and incorrect sensitivity analyses. Comparison of various two-state networks indicate that models incorporating net cubic volume are less sensitive to increases in state neighborhood size. The addition of both a forward "look ahead" heuristic and the "harvest type" state variable to two-state networks improved the objective function value when neighborhoods were large and had nonuniform intra-neighborhood future growth and value potentials. However, these additional efforts resulted in no improvement in the objective function value when small state neighborhoods were used, further supporting the hypothesis that the DP algorithm did find the global optimum solution for the given problem formulation. For. Sci. 43(3):387-395.
A Compatible Growth-Density Stand Model Derived from a Distance-Dependent Individual Tree Model
Authors: Shao Guofan , Shugart Herman H. 
Published: April 2024

Abstract
A compatible growth-density stand model is developed for simulating forest stands with uniformly distributed trees (e.g., square spacing, equilateral triangle spacing, and 1:1.5 row to column ratio tree distribution patterns). The model is based on a distance-dependent individual-tree competition model. The independent variable in the individual-tree model is Hegyi's (1974) diameter-distance competition index with n = 8. The derived growth density stand model satisfies a necessary boundary condition (i.e., stand growth is zero either when stand density is zero or when stand density reaches to a very high level). The stand density which maximizes stand growth rate can be calculated with this stand model. It is found that stands with an equilateral triangle tree distribution pattern have the greatest growth rate among the three uniform stands. Stand growth in measured forests is more than 10% lower than that predicted in uniform stands. Simulation comparisons suggest that the uneven distribution of trees in such stands can reduce stand growth. For. Sci. 43(3):443-446.
Correlation of Counts of Gypsy Moths (Lepidoptera: Lymantriidae)in Pheromone Traps with Landscape Characteristics
Authors: Sharov Alexei A. , Liebhold Andrew M. , Roberts E. Anderson 
Published: April 2024

Abstract
The effect of landscape characteristics (elevation, slope, aspect, and vegetation) on counts of gypsy moths in pheromone traps was studied in a &gt;5 million ha area in Virginia and West Virginia from 1988 to 1994. Habitat effects on population numbers depend on dominant ecological processes in the area: we define K-, r-, and c-effects as differences in carrying capacity, population growth rate, and colonization rate, respectively, that are associated with different landscape characteristics. To differentiate among these effects, we analyzed individually the following three zones at the expanding front of the gypsy moth population: infested (K-effects), transition (r-effects), and uninfested (c-effects). Among landscape characteristics, elevation was most highly correlated with moth counts. Moth counts increased with increasing elevation in the infested and transition zones (K- and r- effects) which may be associated with good habitats at high elevation. However, the highest average moth counts in the uninfested zone were found at low elevation. Possibly this was a c-effect which resulted from a greater colonization rate in the low-elevation areas where human population densities are greater and the probability of inadvertent transfer of egg masses on human vehicles is increased. The effect of vegetation on moth counts was much less pronounced than the effect of elevation. Moth catches were higher in deciduous and mixed forests than in coniferous forests and nonforested areas. The effect of landscape characteristics on moth captures was stronger in the transition zone than in other zones. For. Sci. 43(4):483-490.
Modeling Dominant Height Growth: Eucalyptus Plantations in Portugal
Authors: Amaro Ana , Reed David , Tomé Margarida , Themido Isabel 
Published: April 2024

Abstract
Difference forms of the well-known Chapman-Richards and Lundqvist-Korf biological growth models are derived for use in modeling dominant height growth using data from remeasured permanent plots. The performance of these models is compared with the performance of the McDill-Amateis difference model for describing dominant height growth of eucalyptus plantations in Portugal. The final model is a difference form of the Chapman-Richards equation with the m shape parameter constrained by initial stand conditions. The model is regional in that there are different estimated parameter values for highly productive sites in the coastal region of Portugal compared to lower productivity sites in the interior. The effect of using overlapping or nonoverlapping measurement intervals in the estimation process is examined with independent data; there appears to be little difference in the predictive ability of the resulting models. For. Sci. 44(1):37-46.