bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technical Note: Nitrogen Supply, Nitrogen Use, and Production in an Age Sequence of Lodgepole Pine
Authors: Olsson Ute , Binkley Dan , Smith F. W. 
Published: April 2024

Abstract
Forest productivity typically declines after reaching a peak early in stand development. Historically this pattern was attributed to constant or declining stand photosynthesis and increasing stand respiration, but this explanation has been largely invalidated by field measurements and modeling. Production in older stands might decline as a result of declining soil nutrient supply. To test this idea, we examined patterns of productivity and nitrogen (N) supply and use in four age classes of lodgepole pine (Pinus contorta Dougl. ex. Loud.) ecosystems in southeastern Wyoming. Aboveground net primary production (ANPP) increased from 2200 kg ha-1 yr-1 at age 30 to 4600 kg ha-1 yr-1 at age 50, then declined to 2000 kg ha-1 yr-1 at age 200. Soil N supply (indexed with ion exchange resin bags) was highest in the 30-yr-old sites, but showed no further pattern with age in older sites. The ratio of ANPP to the supply of N rose sharply from age 30 to age 50, and then declined slowly. The ratio of ANPP to the N actually taken up was high for the three youngest age classes, but declined substantially in the old-growth (200 yr) site. We conclude that the low ANPP of the old-growth stands was probably not driven by changes in stand nutrition; the decline in efficiency of N use indicates some other factor probably constrains productivity of old-growth stands. For. Sci. 44(3):454-457.
Using Expert Judgment to Model Initial Attack Fire Crew Effectiveness
Authors: Hirsch Kelvin G. , Corey Paul N. , Martell David L. 
Published: April 2024

Abstract
An expert judgment elicitation methodology was developed and used to encode subjective assessments of fire crew effectiveness from experienced initial attack crew leaders. During structured individual interviews, experts from four Canadian forest fire management agencies provided assessments of the probability of fire containment (POC) by a "medium" (5- to 7-person) initial attack crew for 35 initial attack scenarios that varied in terms of fire size and head fire intensity. This repeated-measures data was used to develop individual, logistic response curves for 34 of the experts. Analysis of the coefficients of these response curves showed that fire size, fire intensity, and the interaction between size and intensity significantly influenced the POC assessments. Using data for seven ancillary variables concerning the background and experience of the experts, it was found that agency had the greatest influence on the POC estimates. Random coefficient regression modeling was used to develop composite probability of containment models for the entire data set, each agency, and suppression with and without bucketing. For. Sci. 44(4):539-549.
Guided Transect Sampling for Assessing Sparse Populations
Authors: Ståhl Göran , Ringvall Anna , Lämås Tomas 
Published: April 2024

Abstract
Guided Transect Sampling is suggested for transect based surveys when sampling sparse and geographically scattered populations. It is a two-stage design in which wide strips are selected in the first stage followed by a subsampling procedure guided by prior information in the second stage. As a basis for the second stage, the target area is divided into grid-cells containing covariate data obtained, for example, by remote sensing. The general principle can be coupled with different transect based survey methods such as strip sampling or line transect sampling. Also, different strategies for the second stage guidance can be used, resulting in estimators with different properties. In this study, Guided Transect Sampling was compared with a traditional strip survey under different simulated forest conditions. The comparisons indicated that the proposed method can improve the efficiency of transect based inventories of sparse populations. For. Sci. 46(1):108-115.
A Three-Stage Heuristic for Harvest Scheduling with Access Road Network Development
Authors: Clark Mark M. , Meller Russell D. , McDonald Timothy P. 
Published: April 2024

Abstract
In this article we present a new model for the scheduling of forest harvesting with spatial and temporal constraints. Our approach is unique in that we incorporate access road network development into the harvest scheduling selection process. Due to the difficulty of solving the problem optimally, we develop a heuristic that consists of a solution construction stage and two solution improvement stages. We call our approach INROADS and compare it to three other approaches by employing hypothetical example problems with 225 stands (or cut blocks) over a three-period planning horizon. Thirteen example forests that vary in terms of stand value and spatial dispersion are used to evaluate our heuristic, which outperforms the other approaches tested. For. Sci: 46(2):204-218.
Modeling Tree-Ring Growth Responses to Climatic Variables Using Artificial Neural Networks
Authors: Zhang Qi-Bin , Hebda Richard J. , Zhang Qi-Jun , Alfaro René I. 
Published: April 2024

Abstract
Modeling the nonlinear and complex relationships between climate and tree-ring growth is of significance in dendroclimatic studies, but difficult to implement using traditional linear regression approaches. To overcome this difficulty, the technique of Artificial Neural Network (ANN) was employed in this study to develop the growth response models using the climate/growth database for Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) on southern Vancouver Island, Canada. The results show that the ANN models are able to extract nonlinear growth response patterns from the observed climate/tree-ring datasets, and to generate more accurate predictions than multiple linear regression approaches. The ANN-extracted climate-growth relationships can be displayed by scenario analysis; for example, when all other input variables are held fixed at their means, the limiting effect of April-July precipitation on tree growth decreases with increased precipitation. The main difficulty of applying ANN technique in dendroclimatology is the problem of overlearning (i.e., the ANN learns too many specific climate-growth patterns and loses the ability to generalize between similar climate-growth patterns). This problem can be alleviated by carefully designing the ANN, such as reducing the number of input variables, choosing a variety of training/testing sets, designing partially connected architectures with a small number of neurons in the hidden layer, and using early stopping during training process. The reliability of the derived ANN models is assessed by validation on independent testing datasets. The main advantages of the ANN technique over traditional dendroclimatic approaches are its ability to capture nonlinear climate-growth response, and its nonreliance on preassumed functional relationships for describing the observed datasets. The ANN method introduced in this article is sufficiently general to be applicable to many forest ecological modeling applications. For. Sci. 46(2):229-239.
Asymmetric Day/Night Temperature Elevation: Growth Implications for Yellow-Poplar and Loblolly Pine Using Simulation Modeling
Authors: Constable John V.H. , Retzlaff William A. 
Published: April 2024

Abstract
Using the TREGRO simulation model we examined the relative impact of asymmetric and symmetric elevations of day/night temperatures on 3 yr biomass gain of yellow-poplar (Liriodendron tulipifera L.) and loblolly pine (Pinus taeda L.). Temperature elevation scenarios used were: (1) an asymmetric 0.3°C/0.9°C increase in day/night temperature (T + 0.3/0.9) as observed since the turn of the century; (2) a symmetric 4°C elevation during both day and night periods (T + 4) as predicted by general circulation models; and (3) an asymmetric 2°C/6°C elevation of day/night temperature (T + 2/6). TREGRO incorporates temperature effects on photosynthesis, respiration, growth rate, and phenology. In both species for all temperature elevation scenarios, respiratory increases exceeded photosynthetic increases and reduced belowground growth. In yellow-poplar, belowground growth was reduced by 7.6% in the T + 0.3/0.9 scenario, whereas the T + 4 and T + 2/6 scenarios reduced belowground growth by 145% and 155%, respectively. The elevated temperature scenarios increased total tree biomass of loblolly pine, but belowground growth was reduced by 24%, 111%, and 113% by the T + 0.3/0.9, T + 4, and T + 2/6 scenarios, respectively. Reductions in root biomass at elevated temperatures may influence competitive interactions between forest tree species and susceptibility to environmental fluctuations. For. Sci. 46(2):248-257.
Root Chemistry of Mature Douglas-Fir Differs by Habitat Type in the Interior Northwestern United States
Authors: Moore James A. , Mika Peter G. , Shaw Terry M. 
Published: April 2024

Abstract
Carbon compound concentrations in plant tissues depend on the environment in which plants grow. However, little is known about how these concentrations vary across a range of forest environmental conditions. Our study examined root tissue (phloem, cambium, phellum, and phello-derm) collected from naturally regenerated mature Douglas-fir (Pseudotsuga menziesii var. glauca [Bessn.] Franco) trees in eight stands on three habitat type series encompassing a range of temperature and moisture conditions. The objective was to determine root chemical composition (sugar, starch, phenol, and tannin) differences among the habitat types. Douglas-fir roots collected from dry, warm Douglas fir habitat types had sugar concentrations of 4% compared to 3% for roots from cool, moist habitat types. Root samples collected from Douglas-fir habitat types showed tannin concentrations about double those from grand fir or western redcedar habitat types. Phenol/tannin ratios for the cool, moist habitat types were about double those from warm, dry Douglas-fir habitat types. Roots sampled from western redcedar habitat types had phenol concentrations and phenol/sugar ratios more than 50% higher than those from Douglas-fir and grand fir habitat types. We speculate that root chemistry of Douglas-fir growing on Douglas-fir habitat types could make them more drought resistant but less disease resistant, while Douglas-fir growing on western redcedar types would be less drought resistant but more disease resistant. Douglas-fir growing on warm, dry sites allocated more carbon to tannin production and less to phenols. FOR. SCI. 46(4):531–536.
Optimal Forest Conservation: Competitiveness Versus Green Image Effects
Authors: Koskela Erkki , Ollikainen Markku 
Published: April 2024

Abstract
This article provides a theoretical framework to study the behavioral and welfare effects of forest conservation, which leads to a binding harvesting constraint for landowners. The economy is modeled as a three-stage game by the interaction of the government's conservation policy, with consequent adjustments in the domestic timber market, and in output determination in a Cournot rivalry with the foreign forest industry. More specifically, we study how the forest industry's competitiveness constrains forest conservation and whether the “green image” demand resulting from forest conservation compensates the loss in competitiveness. It is shown that although the green image effect may locally be strong enough to even increase the profits of the domestic forest industry, at the socially optimal forest conservation level it never dominates the competitiveness effect. Hence, there is a trade-off between forest conservation and competitiveness. These findings are robust to the issue of whether timber markets are perfectly or imperfectly competitive. FOR. SCI. 47(2):178–187.
Estimating Contingent Values for Protection from Wildland Fire Using a Two-Stage Decision Framework
Authors: Winter Gregory J. , Fried Jeremy S. 
Published: April 2024

Abstract
The ongoing expansion of human populations into wildland areas dominated by flammable vegetation, and the concomitant increased frequency of uncontrolled wildfires that result in losses of property and human lives, has raised new questions about the optimal level of fire protection. The morphing of the problem conception from minimizing costs plus losses of natural resources to responding to the concerns of people whose homes are at risk has stimulated fire protection planners to account for potential changes in people's well-being beyond what is reflected by insured value. Knowing the perceived value of an increase in collective (agency-provided) fire protection that achieves a risk reduction target can contribute much to policy debates on the restructuring and funding of fire protection infrastructure and fuel management.
To evaluate the utility of contingent valuation for assessing such risk reduction value, the value of collective fire protection at the wildland-urban interface was assessed for residents of a Michigan jack pine forest. Seventy-five percent of the 265 residents interviewed chose to participate in a hypothetical market for a 50% reduction in risk and, on average, were willing to pay over $57 a year for such risk reduction. Results were consistent with a two-stage decision model: (1) participation in the hypothetical market for risk reduction, and (2) how much the risk reduction is worth. Homeowner risk perception and objectively assessed risk both influenced the probability of market participation. For market participants, willingness to pay was related to property value and household income, suggesting that value at risk and ability to pay weigh heavily in this decision. FOR. SCI. 47(3):349–360.
Forest Productivity, Leaf Area, and Terrain in Southern Appalachian Deciduous Forests
Authors: Bolstad Paul V. , Vose James M. , McNulty Steven G. 
Published: April 2024

Abstract
Leaf area index (LAI) is an important structural characteristic of forest ecosystems which has been shown to be strongly related to forest mass and energy cycles and forest productivity. LAI is more easily measured than forest productivity, and so a strong relationship between LAI and productivity would be a valuable tool in forest management. While a linear relationship has been observed between LAI and forest productivity, most of these data have been collected in needle-leaved evergreen stands. The generality and consistency of the relationship between LAI and productivity has not been as well established for deciduous forests.
Leaf area index (LAI) and aboveground net primary production (ANPP) were measured on 16 forest stands in the southern Appalachian Mountains. These stands span a range of elevation, slope position, temperature, and moisture regimes. LAI averaged 5.8 m2 m-2 and ranged from 2.7 to 8.2. ANPP averaged 9.2 Mg ha-1 yr-1 and ranged from 5.2 to ll.8 Mg ha-1 yr-1.
LAI and ANPP decreased significantly from cove to ridge sites, and ANPP decreases significantly from low to high elevation (P &lt; 0.05, linear regression slope). Elevation-related differences in ANPP do not appear to be due to changes in precipitation, leaf nitrogen content, or site N mineralization rates.
Linear ANPP-LAI equations fit to the data measured in this study were significant (P &lt; 0.05). These relationships were not significantly different (P &gt; 0.1) from linear relationships based on data reported in most other studies of ANPP and LAI in eastern deciduous forests of North America. However, the slope of a linear regression model based on North American eastern deciduous forests was significantly different (P &lt; 0.05) from one based on data collected in temperate deciduous forests for the rest of the globe. The differences were slight over the range of observed data, however, and the difference may be due to a narrower range of data for North American deciduous forests. For. Sci. 47(3):419–427.
African Rain Forest Ecology and Conservation: An Interdisciplinary Perspective
Authors: Baker Timothy R. 
Published: April 2024

Abstract
Current conservation strategies focus on achieving sustainable development by viewing the protection of species and habitats within a broader economic and social context. This approach places complex demands on conservation projects, particularly within the African rain forest, with its great biological, political, and historical diversity. Originally dating from a conference organized by the Wildlife Conservation Society in 1993, this book brings together contributions that allow the examination of whether successful, integrated strategies are evident within African rain forest conservation.
Examining Different Concepts for the Development of a Distance-Dependent Competition Model for Red Pine Diameter Growth Using Long-Term Stand Data Differing in Initial Stand Density
Authors: Larocque G.R. 
Published: April 2024

Abstract
Red pine (Pinus resinosa Ait.) data collected from age 13 to age 43 in a spacing trial were used to develop a distance-dependent individual-tree diameter growth model. The traditional concept of zone of influence in competition indices was redefined, and differences in asymmetry in above- and below-ground competition were represented. The availability of remeasured crown dimensions data allowed for realistic representation of the dynamics of crown interference at the canopy level. Diameter at breast height (dbh) increment was expressed in terms of absolute growth rate, relative growth rate, and ratio of absolute growth rate to crown width. The best relationships accounted for at least 80% of the variability in dbh increment. When tested on an independent data set, the model predicted dbh increment relatively accurately under different conditions of stand density. In particular, the change in dbh size distribution with the increase in competitive stress was well represented. FOR. SCI. 48 (1):24–34.
Competitive Effects on Plantation White Spruce Saplings from Shrubs That Are Important Browse for Moose
Authors: Posner Scott D. , Jordan Peter A. 
Published: April 2024

Abstract
Conifer planting is often accompanied by herbicide control of surrounding broadleaf, woody plants that may interfere with conifer growth, a process that releases conifers from competitive suppression. Because potential competitors often provide browse for wildlife, their removal may conflict with objectives in multiple-resource management. While some agencies, such as the USDA Forest Service (USFS), have greatly reduced herbicide use, many other timber producers still rely on chemicals to release conifers from competing vegetation. In northeastern Minnesota, where moose (Alces alces) are a highly valued resource, we studied impacts of broadleaf shrubs on 4- to 16-yr-old white spruce (Picea glauca) along with the extent of browsing by moose on these shrubs. Height, diameter, and current vertical growth increment of spruce were compared among four levels of presence (density strata) of shrubs immediately surrounding each sapling. Spruce grew as well or better in the low and medium density strata as in the no-shrub stratum. In the high density stratum, height and growth increment, particularly in 10- to 16-yr-old spruce, appeared reduced. Presence of shrubs seemed to reduce frost damage in young spruce. Moose browsing reduced height of most shrub species, suggesting that these animals provide a release effect on adjacent spruce. We recommend a release strategy that avoids reduction of shrubs beyond the level that assures normal growth in young spruce, so as both to minimize loss of browse for wildlife and avoid unnecessary silvicultural costs. FOR. SCI. 48(2):283–289.
Book Reviews: The Ecology and Silviculture of Oaks
Authors: Keith Moser W. 
Published: April 2024

Abstract
In writing The Ecology and Silviculture of Oaks, Paul Johnson, Stephen Shifley, and Robert Rogers have performed a tremendous service to the forestry community, and the hardwood forestry community in particular. Although there have been several books on hardwoods and numerous symposia on oak ecology and management over the years, this volume provides a centralized, albeit expensive, explanation and reference to a significant body of information focusing on the various species of oaks. What was most informative and valuable to me, however, was how this book also presented a template for understanding the ecology and management of all shade-intolerant to mid-tolerant species.
A Mixed-Integer Formulation of the Minimum Patch Size Problem
Authors: Rebain Stephanie , McDill Marc E. 
Published: April 2024

Abstract
Forest harvest scheduling models have addressed wildlife habitat concerns in a variety of ways. One way is through minimum patch size constraints specifying that a certain amount of the forest must consist of patches meeting both minimum size and minimum age requirements. Patch size requirements may be necessary because a forest with only small patches of mature habitat may not be able to support populations of some wildlife species. Maximum harvest opening size constraints, which are often imposed for legal or policy reasons, tend to divide forest habitat into small patches. Minimum patch size constraints may be able to help mitigate the negative impact of maximum harvest opening size restrictions. Patch size requirements have been considered elsewhere, but a mixed-integer linear programming (MILP) formulation has never been presented. This article presents such a formulation, which allows minimum patch size problems to be solved using the branch and bound algorithm available through commercial solver packages. An example problem is formulated, solved, and discussed. For. Sci. 49(4):608–618.
Local Modeling of Tree Growth by Geographically Weighted Regression
Authors: Zhang Lianjun , Shi Haijin 
Published: April 2024

Abstract
The spatial heterogeneity of multivariate relationships between tree growth and diameter is explored using geographically weighted regression (GWR). GWR attempts to capture spatial variation by calibrating a multiple regression model fitted at each tree in a sample plot, weighting all neighboring trees by a function of distance from the subject tree. GWR produces a set of parameter estimates and model statistics (e.g., model R2) for each tree in the sample plot. It is evident that the GWR model not only predicts individual tree growth better than the traditional ordinary least-squares model, but also provides useful information on the nature of the growth variation caused by neighboring competitors and surrounding environmental factors. The parameter estimates and model statistics of the GWR model can be mapped using visualization tools, such as geographic information systems (GIS), to illustrate local spatial variation in the regression relationship under study. Consequently, the influence of microsite variation, competition status, growth potential, and the impacts of management activities on trees can be evaluated, tested, modeled, and readily visualized. GWR is a useful tool that provides much more information on spatial relationships to assist in model development and further our understanding of spatial processes. FOR. SCI. 50(2):225–244.