bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Solution Method for Uneven-Aged Management Applied to Norway Spruce
Authors: Wikström Peder 
Published: April 2024

Abstract
The uneven-aged management problem is to determine the management regime for an existing stand over an infinite time horizon, without ever clearcutting it. A new solution method to solve this problem is presented and demonstrated on simulated Norway spruce stands with different initial stand structures. Diameter distributions were used as a convenient way to describe these structures. The method, which puts much effort into determining the timing of harvest activities, is based on Tabu search and greedy heuristics. The growth dynamics were described with a single tree simulator. Different problem approaches for this problem were adopted to maximize the net present value (NPV) of harvested trees, with or without steady-state constraints. With no such constraints, a finite time horizon approximates the general management problem, while the steady-state constraints involved fixed and equilibrium endpoints. The fixed endpoint was a reverse J-shaped diameter distribution, and its purpose was to mimic the structure of a virgin stand. Analysis of economic efficiency, productivity. and managerial implications were made. With the method used and for the endpoint problems, the conversion strategy, conversion length. and steady-state diameter distribution were determined simultaneously. The Kolmogorov-Smirnov measure was used to describe the similarity between diameter distributions and was put directly into the constraints. The infinite approximation is suggested as the best problem formulation as it, in contrast to a steady-state approach, does not assume that a resource system reaches a climax, eliminates the need to define a diameter class width, and involves no fixed cutting cycles. The even-aged management problem, which is to determine the best period for clearcutting and the best thinning regime that precedes the clearcut, while recognizing the soil expectation value, was analyzed for comparison. The method is flexible, independent of the kind of growth simulator used, and can, for example, be directly applied to a diameter class model. FOR. SCI. 46(3): 452–463.
Persistence of Growth Variation in Tree-Ring Chronologies
Authors: Yoo Seung Jick , Wright Brian D. 
Published: April 2024

Abstract
We infer baseline response to climate of the growth of trees in California dendroclimatological samples, adopting linear and nonlinear approaches and using the expected accumulated impact of a state change as one measure of persistence. Many samples exhibit two quite distinct growth states. Timing of high and low growth states is highly heterogeneous across locations, and regional aggregation seriously understates the size and persistence of local growth changes. If climate is a dominant factor in local tree growth, then local climate is not well represented by an aggregate regional index. FOR. SCI. 46(4):507–520.
Emergy Evaluation of Reforestation Alternatives in Puerto Rico
Authors: Odum Howard T. , Doherty Steven J. , Scatena Frederick N. , Kharecha Pushker A. 
Published: April 2024

Abstract
Six alternative ways of reforesting degraded lands in Puerto Rico were evaluated using emergy (spelled with an “m”). Emergy and its economic equivalent, emdollars, put the contributions of environmental work and human services on a comparable basis. This article shows the emergy method for evaluating forest contributions to public benefit and its use to select alternatives for reforestation. Emdollar values were compared for six scenarios for reforestation of degraded land in Puerto Rico: (1) the natural succession within or adjacent to mature forest; (2) reforestation from the spread of the exotic tree siris (Albizia lebbek); (3) reforestation with plantations of siris and mahogany for harvest; (4) reforestation by leaving plantations unharvested; (5) direct planting of seedlings of many species; and (6) starting patches of forest by massive transfer of topsoil, seed bank, and roots. After energy systems diagrams were made for each reforestation alternative, data were assembled and evaluation tables prepared that estimated the emergy required for: (1) canopy closure and (2) developing species complexity if left unharvested. To explain the method, detailed calculations were included for one of the alternatives, exotic Albizia lebbek plantation on 11 yr harvest cycle.All alternatives generated net public benefit (emdollar yield ratios 4.2 to 24.3). The emdollar value of a closed canopy developed in 10 to 20 yr ranged from 20,000 to 48,000 em$ /ha, whereas the economic costs were $1200 to $9700. For complex forest development in 25 to 60 yr, values ranged from 63,000 to 118,000 em$ /ha, much higher than economic costs of $4000 to $12,000/ha. Highest public benefit per dollar cost came from succession (24.7 em$/$) and exotic colonization (19.1 em$/$). Highest potential monetary returns were from exotic spread (15.1 $/$) and plantations (17.9 and 14.5 $/$). Stand quality after 60 yr, as measured by the transformity (emergy/energy), was largest in mahogany plantation (6.4 × 10 4 sej/J) and succession forest (3.9 × 104 sej/J). FOR. SCI. 46(4):521–530.
Alternative Measurements of Productive Efficiency in the Global Bleached Softwood Pulp Sector
Authors: Yin Runsheng 
Published: April 2024

Abstract
In this article, we conduct a productive efficiency analysis using the two major methods: stochastic frontier analysis (SFA) and data envelopment analysis (DEA). First, we demonstrate the steps and assumptions involved in SFA and DEA, and highlight their strengths and weaknesses. Then we apply them to the case of bleached softwood kraft pulp production to derive technical and allocative efficiency measures for 102 mills in the world. We find that in general, the SFA cost-efficiency levels are higher than their DEA counterparts, and much of the cost inefficiency is caused by inappropriate input mix, or allocative inefficiency, instead of the way with which inputs are converted into outputs, or technical inefficiency. In addition, SFA and DEA results rank some of the producers in different orders. We also find that while cost-efficiency levels vary in different regions, most producers have substantial opportunities to make improvements. Finally, we discuss implications of our study. FOR. SCI. 46(4):558–569.
Process Models as Tools in Forestry Research and Management
Authors: Johnsen Kurt , Samuelson Lisa , Teskey Robert , McNulty Steve , Fox Tom 
Published: April 2024

Abstract
Forest process models are mathematical representations of biological systems that incorporate our understanding of physiological and ecological mechanisms into predictive algorithms. These models were originally designed and used for research purposes, but are being developed for use in practical forest management. Process models designed for research typically require complicated and intensive data, whereas models designed for management strive to use simpler and more readily available data and provide predictions useful for forest managers. In this article, we review some different types of process models, examine their requirements and utility in research and forest management, and discuss research priority areas that will increase their accuracy and application. We conclude that soil and nutritional limitations are the most difficult model components in predicting growth responses using process models. FOR. Sci. 47(1):2–8.
Evaluation of Modeled Carbon Fluxes for a Slash Pine Ecosystem: SPM2 Simulations Compared to Eddy Flux Measurements
Authors: Clark Kenneth L. , Cropper Wendell P. , Gholz Henry L. 
Published: April 2024

Abstract
A process-based model (SPM2) was developed to simulate net hourly exchanges of carbon for slash pine (Pinus elliottii var. elliottii) ecosystems in north-central Florida, and simulated values were compared to those obtained using eddy covariance measurements above the canopy. The SPM2 simulated relatively low hourly rates of net carbon exchange at high irradiance during the day, especially during the month of May. This discrepancy contributed the most to differences between the two approaches, and suggests that the model underestimates the maximum rate of leaf-level net photosynthesis during the period of rapid growth in the spring. The SPM2 also simulated lower net carbon release during the nighttime across the range of air temperatures, relative to eddy covariance measurements. As a result of these discrepancies, accumulated daytime and nighttime sums were quite different between the two approaches. However, once results were aggregated over 24 hr, differences between simulations and measurements were insignificant at all but the highest and lowest daily net carbon gain values. Annual estimates for 1996 were similar: 693, 719, and 745 g C m-2 yr-1 for the SPM2 model, eddy covariance measurements and mass balance measurements, respectively. This model evaluation has lead to specific research questions for guiding further model development. FOR. Sci. 47(1):52–59.
Biophysical Site Indices for Shade Tolerant and Intolerant Boreal Species
Authors: Ung Chhun-Huor , Bernier Pierre Y. , Raulier Frédéric , Fournier Richard A. , Lambert Marie-Claude , Régnière Jacques 
Published: April 2024

Abstract
Two variants of a biophysical site index model were derived for two shade-tolerant boreal species (Abies balsamea [L.] Mill., and Picea mariana [Mill.] BSP), and two shade-intolerant boreal species (Populus tremuloides Michx., and Betula papyrifera Marsh.). The reduced model is based on the widely used assumption that the relationship between height and age of dominant trees depends solely on site properties: i.e., four climatic variables (degree-days, vapor pressure deficit, aridity index, and precipitation), and one edaphic variable (soil water-holding capacity). The full model is based on the further assumption that site index also depends on the stand successional stage represented by the dbh distribution index. The reduced model is accurate and unbiased for both intolerant species, but it becomes inaccurate and underestimates the mature stand dominant height for both tolerant species. The full model is equivalent to the reduced model for both intolerant species, but becomes two or three times more accurate and unbiased for both tolerant species. When incorporated into a growth and yield model as the site quality index, the reduced model performs as well as the traditional phytometric model (derived solely from an empirical fit of dominant height and age without any biophysical data) for both intolerant species, but it becomes biased for both tolerant species. By contrast, the full model, when used as a site quality index in the growth and yield model, is unbiased and equivalent to the phytometric model for the four species. These results show that the site index of intolerant species can be solely associated with climatic and edaphic variables, but these variables have to be completed by the successional stage for correctly estimating the site index of the tolerant species. FOR. Sci. 47(1):83–95.
Severe Drought Effects on Mediterranean Woody Flora in Spain
Authors: Peñuelas Josep , Lloret Francisco , Montoya Ramón 
Published: April 2024

Abstract
The severe drought in 1994 damaged the woody flora of central and southern Spain (80% of the 190 studied sites presented drought-damaged species). In 1996, after a wet year, 67% of the sites were still affected. Different degrees of damage and recovery were found among different functional types (trees or shrubs), and genera of different evolutionary history (Mediterranean or pre-Mediterranean). The Mediterranean genera, mostly shrubs evolved under Mediterranean climate conditions, i.e., later than 3.2 M years ago in the Pliocene, were more damaged by the drought than the earlier evolved pre-Mediterranean genera, mostly trees. However, the Mediterranean genera were more resilient and recovered much better after the following wet year. FOR. SCI. 47(2):214–218.
A Longitudinal Study of Environmental Attitudes of Women and Gender Diversification in the U.S. Forest Service 1990–1996
Authors: Brown Greg , Harris Charles C. 
Published: April 2024

Abstract
The USDA Forest Service has been dominated by white, male foresters. Beginning in the mid-1970s, the agency was compelled legally and morally to begin diversifying its workforce by race, gender, and profession. Concurrent with workforce diversification efforts, the agency confronted demands from the courts, Congress, and interest groups to change national forest management by emphasizing national forest preservation over the production of commodities such as timber and livestock forage. This study examines the role of women as potential organizational change agents by analyzing survey data collected from two national studies of the Forest Service in 1990 and 1996. Results from the 1996 study indicate that women continue to exhibit higher levels of general environmental concern than men, suggesting their role as potential “saviors” in helping the agency to make the transition to increased emphasis on ecosystem management. Conversely, diversification of the Forest Service workforce continues to be highly contentious, with some employees feeling that the recruitment and promotion of women without adequate training and/or experience have left the agency unprepared to meet complex demands. The inability of the Forest Service to satisfy multiple, conflicting constituencies in the face of agency downsizing suggests the role of women as “scapegoats,” whose perceived lack of experience is responsible for agency shortcomings. The authors suggest that the historical convergence of workforce diversification with changes in national forest policy inevitably place women in the conflicting roles of both “saviors” and “scapegoats.” FOR. SCI. 47(2):246–257.
Burning Characteristics of Needles from Eight Pine Species
Authors: Fonda Richard W. 
Published: April 2024

Abstract
Ponderosa pine (Pinus ponderosa), Jeffrey pine (P. jeffreyi), longleaf pine (P. palustris), and south Florida slash pine (P. elliottii var. densa) are fire resisters. Trees of these species are able to survive the direct effects of wildfires. Monterey pine (P. radiata), knobcone pine (P. attenuata), sand pine (P. clausa), and jack pine (P. banksiana) are fire evaders. Trees of these species are killed by wildfire, but species survive on the postfire site via seed germination. Needles were burned in a 2×2 factorial experiment to compare these eight species, all of which are prominent in fire-related communities. The experiment tested two factors—fire adaptive strategy (resisters vs. evaders), geographic region (western vs. eastern United States)—and interactions between those two factors. Flame height, flame time, ember time, burn time, percent fuel combusted, and mean rate of weight loss were measured. Longleaf pine, ponderosa pine, and south Florida slash pine had the highest values for flame height, percent fuel combusted, and mean rate of weight loss. Knobcone pine and Monterey pine had the longest ember time and burn time. Sand pine and jack pine had the longest flame time. Resisters tested highest in flame height, percent fuel combusted, and mean rate of weight loss. Evaders had greater flame and burn times. Western pines were significantly greater than eastern pines in all burning characteristics except flame time and mean rate of weight loss. Significant interactions between fire adaptive strategy and geographic region existed for all burning characteristics except mean rate of weight loss. The interaction was accounted for primarily by differences between western evaders, which had some of the highest values for each characteristic, and eastern evaders, which had some of the lowest values. FOR. SCI. 47(2):390–396.
BOOK REVIEWS: Writing and Presenting Scientific Papers
Authors: Covert Sarah F. 
Published: April 2024

Abstract
Effective writing and oral presentation skills are essential tools for any scientist. Nothing less than one's employment, grant support, publication record, and scientific impact all depend on these abilities. It is surprisingly rare, however, for graduate training programs to address these issues through formal study. As a consequence, I suspect that many young scientists enter the world of independent research with less than stellar writing skills, and I know from unfortunate experience that many seasoned scholars have yet to fully master the art of the scientific seminar. There is a clear need for instruction in these areas, but how can graduate trainers effectively teach their students these skills when they most likely acquired them only through the horrors of trial and error, or the luck of natural talent? Furthermore, how can an established scientist or a motivated student polish his or her communication skills through independent study? Malmfors, Garnsworthy, and Grossman provide lucid and concise answers to these questions in their very useful, no-nonsense handbook.
BOOK REVIEWS: Invasive Plants of California's Wildlands
Authors: Pimentel David 
Published: April 2024

Abstract
Invasive Plants of California's Wildlands provides detailed information on the biology and control of 78 nonnative plant species that were listed as Exotic Invasive Plants of Greatest Ecological Concern by the California Exotic Pest Plant Council. These invasive, nonnative species were discussed because they are already growing wild in California and are causing or have the potential to be a serious threat to state parks, preserves, and other wildlands.
Optimal Private and Public Harvesting under Spatial and Temporal Interdependence
Authors: Koskela Erkki , Ollikainen Markku 
Published: April 2024

Abstract
This article extends the Hartman model to include the case where two adjacent stands may be interdependent in the provision of amenity services. We show first that the relationship between the focal and exogenous rotation age depends on the nature of their temporal interdependence, that is, on what happens to the degree of substitutability or complementarity between the stands when the rotation age of the private focal stand changes. We then apply this analysis to the determination of public rotation age in a two-stage game where the government first decides on its harvesting, and private harvesting is chosen in the second stage. Several new rules are derived for the socially optimal design of public harvesting depending on the nature of interdependence between private and public stands as well as on whether or not citizens have access to private forests for recreation. FOR. SCI. 47(4):484–496.
Forest Certification: Roots, Issues, Challenges, and Benefits
Authors: Radosevich Steven R. 
Published: April 2024

Abstract
Foresters have been involved in a serious debate with other members of society for at least three decades over the environmental and social consequences of continuing to manage forestlands as they have been. This debate takes many forms, ranging from simple disagreement to new laws and regulations, market boycotts, and even civil disobedience by some members of the public. Foresters and many environmental organizations alike have looked for ways to resolve these ever-present concerns about the environmental, ecological, economic, and social consequences of forest management, while providing incentives for forest landowners to change their practices. Forest certification, as a voluntary, economically driven process, may be the mechanism for resolution to eventually occur, for the debate to end.
Heritability of Ozone Sensitivity in Open-Pollinated Families of Black Cherry (Prunus serotina Ehrh.)
Authors: Lee J.C. , Steiner K.C. , Zhang J.W. , Skelly J.M. 
Published: April 2024

Abstract
First-year seedlings of black cherry, representing 10 open-pollinated families from wild parents, were exposed in CSTR chambers to replicated treatments of 30, 60, 90, and 120 ppb ambient ozone for a 7 hr day-1, 5 day wk-1. Stem height, occurrence of leaf senescence, and visible foliar injury expressed as adaxial stipple were measured weekly during the 10 wk duration of exposure. Basal stem diameters were measured before and after fumigation. Stipple began to occur in week 1 of the 120 ppb ozone treatment, week 2 of the 90 ppb treatment, and week 4 of the 60 ppb treatment. No stipple occurred on any seedlings exposed to 30 ppb ozone. Premature leaf senescence occurred in all treatments, but sooner and more severely at higher concentrations of ozone. Relative diameter growth rates declined as ozone concentrations increased. Families differed significantly in their response to ozone treatments in severity of adaxial stipple, but not in leaf senescence or height or diameter growth. Family heritability estimates for foliar injury, calculated by treatment and week of measurement, were generally above 0.5 in the 90 and 120 ppb ozone treatments. The relative ozone sensitivity of these 10 families under CSTR conditions corresponded well with sensitivity rankings of their 27-yr-old parents, replicated in a clonal seed orchard, and growing under ambient ozone exposures. The existence of localized, heritable variation in ozone sensitivity in wild populations has obvious implications for the use of bioindicators in forest health monitoring. For. Sci. 48(1):111–117.
Modeling Changes in Wildlife Habitat and Timber Revenues in Response to Forest Management
Authors: Marzluff John M. , Millspaugh Joshua J. , Ceder Kevin R. , Oliver Chadwick D. , Withey John , McCarter James B. , Mason C.L. , Comnick Jeffrey 
Published: April 2024

Abstract
Few models evaluate the effects of forest management options on wildlife habitat and incorporate temporal and spatial trends in forest growth. Moreover, existing habitat models do not explicitly consider economic trade-offs or allow for landscape level projections. To address these concerns, we linked standard wildlife habitat suitability models with habitat projections from the Landscape Management System (LMS). LMS integrates spatially explicit forest inventories with forest growth, decay, and silviculture treatment (e.g., planting, thinning, harvesting) models to compare some economic and biological impacts of forest management on wildlife habitats at spatial scales ranging from the individual forest stand to the landscape. We used LMS to quantify pileated woodpecker (Dryocopus pileatus), Cooper's hawk (Accipiter cooperi), and southern red-backed vole (Clethrionomys gapperi) habitat qualities across landscapes and to project habitat changes through time. We modeled five forest management scenarios (including no action, intensive management for timber production, moderate management and intensive management to enhance mature forest structure, and mixed management for wildlife and timber) proposed for the 566 ha Satsop Forest in western Washington. The selected wildlife species' habitats (mixture of mature conifer and deciduous forests) were maximized by simply allowing the forest to grow with no management. However, this cost an estimated $929,539/yr in lost timber revenue. Intensive thinning, replanting, and retention of large trees increased habitat for all focal species and provided $384,558/yr return from timber. Because of potential short-term reductions in habitat that occur during long-term enhancement strategies (e.g., intensive thinning) and limited ability to model understory growth dynamics, monitoring and validation of predictions would be necessary. FOR. SCI. 48(2):191–202.