bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impacts on Economically Optimal Timber Rotations When Future Land Use Changes
Authors: Klemperer W. David , Farkas Daniel R. 
Published: April 2024

Abstract
Based on a perpetual rotation assumption, changes in selected variables will have effects on the even-aged timber clearcut age (rotation) that maximizes net present value using the Faustmann formula. Alternatively, one can assume that landowners project a postharvest change in land use with a land value equal to or exceeding today's Faustmann value and that this future land value is independent of their assumed values for variables like annual costs, annual revenues, stumpage prices, and income taxes. In that case, the impact of changes in the foregoing variables on optimal rotations may be substantially greater, and sometimes in the opposite direction, compared to the standard Faustmann approach. Moreover, a higher estimated postharvest land value can shorten the optimal rotation. With a loblolly pine yield function, these rotation differences are demonstrated, using the standard, perpetual Faustmann formula and a rotation-end land use change adaptation with a fixed projected land value. Appendixes include mathematical verifications. The different interpretations depend on whether one considers the Faustmann land value as the land market value in a general equilibrium sense, or whether one takes the future market value of land as given and performs sensitivity analyses of alternative scenarios. Policy implications are difficult to assess without more research on landowner behavior. FOR. SCI. 47(4):520–525.
A Stochastic Production Frontier Analysis of Polish State Forests
Authors: Siry Jacek P. , Newman David H. 
Published: April 2024

Abstract
This article presents a study of the efficiency of Polish state timber production and management polices following the transition to a more competitive market. The objective is to determine how well the Polish State Forests, which manage 80% of Poland's forestland and supply 85% of its timber, have adjusted, after 40 yr of central planning, to this change. The development and estimation of a stochastic frontier production function is used to analyze and evaluate the efficiency of timber production and the effectiveness of management policies. The empirical results provide evidence for the presence of substantial technical inefficiency, along with some scale economies in timber production. In addition, policies that have led to the creation of smaller forest districts, employment reductions, and logging equipment purchases are largely ineffective and perhaps even counterproductive. On the other hand, a strong support is provided for the continued privatization of forest operations. FOR. SCI. 47(4):526–533.
Large Landscape Scale Analysis of Tree Death in the Adirondack Park, New York
Authors: Manion P.D. , Griffin D.H. 
Published: April 2024

Abstract
We propose that healthy forests depend on quantitatively predictable tree death as a continuous process linked to forest structure and growth. Quantifying a baseline mortality value by forest structure analysis using the Law of de Liocourt allows estimation of forest health by comparing the observed mortality to a baseline value. This method is applicable to large landscape samples, but not generally to individual forest stands. Observed relative mortality per dbh class from a random sample of the Adirondack Park (New York, USA) forest was slightly, but significantly, less than the baseline relative mortality per dbh class required for maintaining size-distribution stability of the forest. This result suggests a changing structure involving increased forest density, or future mortality increase to maintain the current structure. Differences in structure-mortality relationships among the more abundant species indicate changing composition of the forest. This reflects unhealthy conditions in some species (American beech, yellow birch, balsam fir, and red spruce) that are compensated by enhanced development of others (red maple, sugar maple, and eastern hemlock). For. Sci. 47(4):542–549.
Comparison of Estimation Techniques for a Forest Inventory in which Double Sampling for Stratification Is Used
Authors: Williams Michael S. 
Published: April 2024

Abstract
A number of different estimators can be used when forest inventory plots cover two or more distinctly different condition classes. In this article the properties of two approximate Horvitz-Thompson (HT) estimators, a ratio of means (RM), and a mean of ratios (MR) estimator are explored in the framework of double sampling for stratification. Relevant theoretical properties are given, and a simulation study is used to compare the properties of these estimators. It is concluded that the variance of the RM estimator is smaller than that of the approximate HT for the populations studied, but that of the MR estimator is larger. While ratio estimators are known to be biased for small sample sizes, an additional bias also occurs when the population of interest has an edge-effect. The RM classical variance estimator underestimated the true variance in the simulation study. The approximate HT estimators exhibited biases that were generally smaller than those of the RM and MR estimators for populations with an edge-effect. Its classical variance estimator was essentially unbiased. FOR. SCI. 47(4):563–576.
Combining Tabu Search and Genetic Algorithm Heuristic Techniques to Solve Spatial Harvest Scheduling Problems
Authors: Boston Kevin , Bettinger Pete 
Published: April 2024

Abstract
The performance of two new heuristics that combine tabu search with a genetic crossover technique was examined for their usefulness in solving spatially constrained harvest scheduling problems. One heuristic utilized tabu search with 1-opt moves and a genetic crossover technique (TS/GA), and the other utilized tabu search with both 1-opt and 2-opt moves and a genetic crossover technique (TS2/GA). The heuristics were tested on four problems. Three problems used the simple unit-restriction model (URM) to portray greenup constraints, allowing them to be solved with mathematical programming techniques and thus providing a benchmark to compare against the solutions produced by the heuristic techniques. These were considered hypothetical problems, since the datasets were grids, and the age classes were assigned with three different rules. The fourth problem uses an operational dataset and includes both a maximum opening size constraint, which limits the size of an individual opening, and a maximum average opening size constraint, which represents the greenup constraint contained in the American Forest and Paper Association (AF&PA) Sustainable Forestry Initiative (AF&PA 2000). The greenup constraints contained in these problems accurately portray the greenup constraints facing the forest industry in the United States. For the three hypothetical problems, the TS/GA technique found solutions with an objective function value between 96.6% and 99.1% of an estimated optimal value, and between 93.4% to 94.4% of a relaxed linear programming value. The TS2/GA found better solutions for all three hypothetical problems, with the objective function values between 98.2% and 99.7% of the estimated optimal value and the 96.3% to 97.2% of the relaxed linear programming value. Compared with a general tabu search technique that used 1-opt moves (TS), adding the genetic crossover technique resulted in a 2% increase in the objective function value, and adding the 2-opt intensification capability resulted in a further 1.5% improvement. A similar pattern was observed when the problem using the operational dataset was solved. The addition of the genetic crossover technique did not increase the time required to produce a solution to any particular problem, yet the addition of the 2-opt procedure did. TS2/GA required about twice as much time as did TS or TS/GA when applied to the three hypothetical datasets, and 67% more time when applied to the problem using the operational dataset. FOR. SCI. 48(1):35–46.
Growth and Nutritional Interactions of Nutrient-Loaded Black Spruce Seedlings with Neighboring Natural Vegetation Under Greenhouse Conditions
Authors: Imo Moses , Timmer Victor R. 
Published: April 2024

Abstract
Nutrient loading during nursery culture to improve early outplanting performance of black spruce (Picea mariana [Mill.] BSP) seedlings on weed prone sites is increasingly practiced in northern Ontario, but more insight is needed on the competitive mechanisms involved. Vector competition analysis was used to examine nutrient loading on interspecific growth and nutritional interactions between planted seedlings and neighboring natural vegetation under controlled greenhouse conditions. Nutrient loaded and conventional (nonloaded) seedlings were raised in a commercial green-house and then transplanted in bioassay soil substrates retrieved from two forest sites [Hardwood (OG 10) and Feathermoss (OG 4)], with weeds removed or left to grow naturally. Weed control increased seedling growth on the Hardwood substrates (103–194% height increase), but had no effect on the Feathermoss substrates suggesting that no seedling–natural vegetation interactions occurred on the latter site. Nutrient loading, however, countered weed competition on the competition-prone Hardwood site, reflecting the high competitiveness of these seedlings. Vector competition analysis revealed that tree-vegetation interactions on the Hardwood site caused antagonistic nutrient dilution primarily due to competition for N. Nutrient interactions were more symmetric with nutrient-loaded trees, indicating that these seedlings were less sensitive to competition than were nonloaded seedlings. For. Sci. 48(1):77–84.
Correction for Slope in Point and Transect Relascope Sampling of Downed Coarse Woody Debris
Authors: Ståhl Göran , Ringvall Anna , Gove Jeffrey H. , Ducey Mark J. 
Published: April 2024

Abstract
In this article, the effect of sloping terrain on estimates in point and transect relascope sampling (PRS and TRS, respectively) is studied. With these inventory methods, a wide angle relascope is used either from sample points (PRS) or along survey lines (TRS). Characteristics associated with line-shaped objects on the ground are assessed, e.g., the length or volume of downed logs. In their basic forms, the methods only work in flat terrain, and thus bias is incurred under sloping conditions.
Two different possibilities to correct for bias due to slope are presented. The first one involves using a slightly modified relascope device and making a measurement of the angle of inclination of each sampled object. The second involves applying correction factors based on the steepness of the terrain in the area surveyed. However, it is shown that moderate slopes cause only limited bias and in such cases there is little need to adjust the measurement procedures or apply correction factors. For. Sci. 48(1):85–92.
Regional and National Issues for Forest Wildlife Research and Management
Authors: DeStefano Stephen 
Published: April 2024

Abstract
Biologists and managers face a broad range of issues related to research and management of forest wildlife. To assess current trends in research, I reviewed 12 scientific journals (1992–2001) that published articles on wildlife, general ecology, and forestry and summarized articles by location, topic, issue, and species. To assess management concerns and issues, I interviewed professional biologists from across the United States, asking their opinions on important forest wildlife topics, approaches to improve research design, how management differs on public versus private lands, and which species they thought were underrepresented, overrepresented, or of special concern in their region. Most scientific articles focused on habitat selection, effects of forest alteration, and demography of birds and mammals. Herpetofauna (i.e., amphibians and reptiles) and invertebrates, although the subjects of some studies, made up only 10% each of all research papers. Biologists were most concerned with the alteration of forest vegetative structure due to timber harvest and its effects on wildlife populations and communities, but also recognized other issues such as changes in natural disturbance patterns such as fire, effects of road building, and loss of early successional vegetative communities as well as fragmentation of older forests. Most biologists agreed that long-term, large-scale, experimental studies, which document the demographic response of forest wildlife to alterations in forest cover, are needed. FOR. SCI. 48(2):181–189.
Models for Mapping Potential Habitat at Landscape Scales: An Example Using Northern Spotted Owls
Authors: McComb William C. , McGrath Michael T. , Spies Thomas A. , Vesely David 
Published: April 2024

Abstract
We are assessing the potential for current and alternative policies in the Oregon Coast Range to affect habitat capability for a suite of forest resources. We provide an example of a spatially explicit habitat capability model for northern spotted owls (Strix occidentalis caurina) to illustrate the approach we are taking to assess potential changes in habitat capability for vertebrates across the Coast Range. The model was based on vegetation structure at five spatial scales: the potential nest tree, a 0.5 ha potential nest patch, 28 ha around a potential nest patch, 212 ha around a potential nest patch, and a 1,810 ha home range area around a potential nest patch. Sensitivity analyses indicated that the proportion of the 28 ha patch in large trees around a potential nest patch, and the number of potential nest trees per ha in the nest patch, had the greatest influence on habitat capability estimates. The model was verified using georeferenced locations of spotted owl nests from systematically surveyed areas. Logistic regression analysis indicated that habitat capability scores were significantly associated with the probability of a site having a nest. Alternative model structures were tested during verification to test assumptions associated with four variables. The final model allowed development of a map of habitat capability for spotted owl nesting. The model will be linked to a model of forest dynamics to project changes in habitat capability under alternative land management policies. FOR. SCI. 48(2):203–216.
Floristics and Avian Community Structure: Implications for Regional Changes in Eastern Forest Composition
Authors: Rodewald Amanda D. , Abrams Marc D. 
Published: April 2024

Abstract
Because many forest stands are increasingly dominated by maple (Acer spp.) in eastern North America, there will likely be a relative scarcity of mature oak (Quercus spp.) forests within the next several decades. In an effort to understand how avian communities may be affected by a regional change in forest composition from oak to maple dominance, we compared bird communities in both oak- and maple-dominated forest stands in three seasons (winter, spring, and fall). In 1998 and 1999, birds were surveyed and habitat characteristics were measured in six mature forest woodlots in central Pennsylvania. Total abundance of birds was greater within oak- than maple-dominated stands in all seasons, whereas species richness was greater in oak stands only in the spring. Resident species, long-distance migrants, woodpeckers, bark-gleaners, and 11 individual species were more abundant within oak than maple stands in at least one season. Differences in avian community structure between oak and maple stands were greatest in the fall when oaks produced hard mast and in the spring when insectivorous birds gleaned arthropods from tree substrates. This pattern was consistent with our expectations based on mast characteristics and tree physiognomy of maples and oaks as well as the diet and foraging behavior of birds. Our results suggest that a regional change from oak- to maple-dominated forests may strongly affect avian community structure and populations of some common bird species associated with eastern deciduous forests. FOR. SCI. 48(2):267–272.
The Effect of Gypsy Moth Defoliation on Cavity-Nesting Bird Communities
Authors: Showalter Christopher R. , Whitmore Robert C. 
Published: April 2024

Abstract
Gypsy moths (Lymantria Dispar) kill trees and create snags, a resource vital to cavitynesting birds. With this in mind, population trends of 11 cavity-nesting birds and their relationship to snags in an area that was defoliated by gypsy moths were investigated from 1984 to 1999. Vegetation and bird point-count data from before a major gypsy moth outbreak (1984–1986), during (1987–1988), and after (1989–1999) enabled us to ake inferences about this forest bird community. The combined abundance of the 11 cavity-nesting species examined increased during the years immediately after the outbreak (1989–1993) followed by a decline in the last 6 yr (1994–1999). The abundance of snags also increased from 1989 to 1993 followed by a decline from 1994 to 1999. Regression analysis confirmed that cavity-nesting bird populations were highly associated with snag abundance. These data suggest the importance of snags to cavity-nesting birds and that cavity-nesters were able to take immediate advantage of a new population of snags. FOR. SCI. 48(2):273–281.
Influences of Hardwood Stand Area and Adjacency on Breeding Birds in an Intensively Managed Pine Landscape
Authors: Turner J. Chris , Gerwin John A. , Lancia Richard A. 
Published: April 2024

Abstract
We compared species richness, abundance, and community composition of breeding landbirds among three areal classes of mature hardwood stands within an intensively managed pine (Pinus taeda) landscape in the Lower Coastal Plain of South Carolina. We also compared these community metrics among rotation-age pines (≈20 yr old), the pine matrix (regenerated to rotation-age pine stands comprising 50% of the landscape), and all hardwood stands regardless of area. Approximately 220 fixed-radius point counts were conducted in 1995 and 1996. Species richness (21, 23, and 25 species, respectively) within small (n = 19; 1.0–4.4 ha), medium (n = 17; 6.0–34.4 ha), and large (n = 6; 65–560 ha) hardwood islands within the pine matrix was the same, but the trend was for richness to increase with island area. Forest interior, neotropical migrants dominated all hardwood stand areas. Most species were common to all areal classes, with only a few restricted to a particular areal class. Thus, there was little evidence that these hardwood islands, embedded in a managed pine landscape context, harbored unique bird communities. Species richness (40) was greatest within the matrix of pine stands of all ages, intermediate (32) in hardwood stands, and least (27) in rotation-age pine stands. Hardwood stands supported the highest total bird densities as well as the highest densities of neotropical migrants. Pine stands hosted high densities of both resident and early successional neotropical migrants. We concluded that the presence of hardwood stands embedded within a matrix of different age classes of pine likely allowed forest-interior neotropical migrants typical of hardwood stands to “spill over” into adjacent, structurally similar pine stands and vice versa. FOR. SCI. 48(2):323–330.
The Effect of Forest Roads on the Reproductive Success of Forest-Dwelling Passerine Birds
Authors: King David I. , DeGraaf Richard M. 
Published: April 2024

Abstract
Recent studies indicate that forest roads may affect the distribution of forest-dwelling birds. However, previous studies have not demonstrated any significant effects of forest roads on avian productivity. We studied the effect of maintained and unmaintained forest roads on (1) forest bird nest survival, (2) reproductive parameters of ovenbirds (Seiurus aurocapillus) potentially associated with food abundance, and (3) habitat and microclimate at six sites on the White Mountain National Forest, New Hampshire, during two breeding seasons. Nest survival did not differ between areas near (0–150 m) and far (&gt;150 m) from maintained forest roads, and was marginally (P=0.08) higher in areas near (0–150 m) unmaintained roads. When the 0–150 m distance class was subdivided, however, nest survival was significantly higher within 0–75 m of maintained roads than &gt;75–150 m away. Ovenbird nest initiation dates, clutch size, and fledging success did not differ between areas near (0–150 m) and far (&gt;150 m) from maintained and unmaintained forest roads, and this result did not change when the distance class 0–150 m from roads was subdivided. There were no relationships between habitat or microclimate and distance from maintained roads. We conclude that small, unsurfaced forest roads at low road density do not result in decreases in forest passerine bird productivity in extensively forested areas in New England. FOR. SCI. 48(2):391–396.
Herpetofaunal Response to Gap and Skidder-Rut Wetland Creation in a Southern Bottomland Hardwood Forest
Authors: Cromer Robert B. , Lanham Joseph D. , Hanlin Hugh H. 
Published: April 2024

Abstract
We compared herpetofaunal communities in recently harvested gaps, skidder trails, and unharvested depressional wetlands to assess the effects of group-selection harvesting and skidder traffic on reptiles and amphibians in a southern bottomland hardwood forest. From January 1, 1997 to December 31, 1998 we captured 24,292 individuals representing 55 species of reptiles and amphibians at the Savannah River Site in Barnwell County, South Carolina. Forty-two species (n = 6,702 individuals) were captured in gaps, 43 species (n = 8,863 individuals) were captured along skid trails between gaps and 43 species (n = 8,727 individuals) were captured in bottomland depressions over the 2 yr period. Three vegetation variables and six environmental variables were correlated with herpetofaunal abundance. Salamander abundance, especially for species in the genus Ambystoma, was negatively associated with areas with less canopy cover and pronounced rutting (i.e., gaps and skidder trails). Alternatively, treefrog (Hylidae) abundance was positively associated with gap creation. Results from this study suggest that group selection harvests and skidder rutting may alter the herpetofaunal species composition in southern bottomland hardwoods by increasing habitat suitability for some species while diminishing it for others. FOR. SCI. 48(2):407–413.
Polya Posterior Frequency Distributions for Stratified Double Sampling of Categorical Data
Authors: Magnussen Steen , Köhl Michael 
Published: April 2024

Abstract
Estimates of category frequencies in stratified double sampling are generally obtained by methods of maximum likelihood assuming a multinomial distribution of data. Although the distribution of estimation errors is asymptotically normal, a reliance on the normal assumption for inference can be problematic for low frequency categories (&lt;10%) and small sample sizes (&lt;1,000). In these situations, a Bayesian approach appears more robust. A vague Dirichlet prior is adopted to compute a Polya posterior distribution. In a simulation study of sampling from eight small-to medium-sized populations, we found that the resampling distributions of maximum likelihood estimates were generally closer to the Polya posteriors than to the assumed normal distributions. Resampling distributions and Polya posteriors deviated frequently and significantly from a normal distribution. A Polya posterior was often orders of magnitude faster to compute than a resampling distribution. FOR. SCI. 48(3):569–581.