bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method for Characterizing and Mimicking Forest Canopy Gaps Caused by Different Disturbances
Authors: Lundquist John E. , Beatty Jerome S. 
Published: April 2024

Abstract
Forest canopy gaps are measurable indicators of past small-scale disturbances. These disturbances can impact forest stand dynamics in ways that help maintain and enhance many ecosystem values. Impacts are commonly assessed using timber production metrics based on average stand values, but metrics based on smaller scales are needed to assess impacts on nontimber resources. In this study, we developed a multivariate method of quantitatively characterizing individual canopy gaps in Douglas-fir/grand fir stands in the Blue Mountains of eastern Oregon. We then established a reference or target range of variability by profiling gaps according to numbers of snags, downed logs, gap size and shape, and recolonizing vegetation. Cluster analysis, multidimensional scaling, and classification “trees” were used with these profiles to quantify similarity among individual gaps. Gaps fell into four groups, which could be interpreted as three ecologically functional groups on the basis of their role in stand development. Gaps caused by the same agents commonly fell within the same functional group: (1) flooding, logging, spruce budworm, and windfall cause stand level impacts that reset the stand development sequence; (2) bark beetles, tree fall, and root diseases cause within stand impacts that altered the rate of stand development; and (3) stem decay and dwarf mistletoe, and, under some circumstances, all disturbance agents, could kill trees yet have no impact on stand development except create space into which neighboring trees expand. We present a simple test to monitor how gaps change with silvicultural manipulations. Results indicate that this method offers (1) a way to systematically guide silvicultural manipulations aimed at mimicking natural disturbances at the canopy gap scale, and (2) a way to monitor the effectiveness of such silvicultural treatments and management actions using gap-based silviculture prescriptions. FOR. SCI. 48(3):582–594.
Resource Assessment of Non-Wood Forest Products: Experience and Biometric Principles
Authors: Pilz David 
Published: April 2024

Abstract
Forest managers increasingly recognize that management of non-wood forest product (NWFP) harvesting is important for conserving biological diversity and sustaining human use of forests. Importantly, many of these products, and the forests they grow in, are integral to the persistence of indigenous cultures. Similarly, rural communities are more likely to support forest conservation or longer timber rotations if they can annually harvest and market products derived from local forests. Managing NWFP resources poses a daunting task, however, because such products are numerous and diverse; the organisms that produce them differ widely in form, abundance, distribution, and autecology; and harvesting typically occurs in a complex social, economic, political, land tenure, and forest management context. Nevertheless, forest managers, researchers, development workers, harvesters, and affected local communities agree that assessing the status of, and changes in, resource abundance is central to sustainable NWFP management.
Economic Analysis of the Canada–United States Softwood Lumber Dispute: Playing the Quota Game
Authors: van Kooten G. Cornelis 
Published: April 2024

Abstract
The Canada–U.S. Softwood Lumber Agreement (SLA) was the latest measure to restrict Canadian exports of softwood lumber to the United States. Rather than a countervail duty or export tax, SLA employed a quota that provides a large windfall (quota) rent to Canadian lumber producers in addition to extra quasi-rents to U.S. producers, all at the expense of U.S. consumers. However, Canadian producers have not taken full advantage of the quota regime to maximize their overall gains, which exceed what they could earn under free trade or an export/import tax. This is demonstrated using a theoretical framework and numerical illustration. It is shown that the net gain to Canadian producers does not occur when the quota rent is maximized, but rather when the sum of producer surplus and quota rent is maximized. It is also argued that the existence of resource rents from logging does not constitute a subsidy to lumber producers. It is concluded that, from Canada's perspective, export quotas are preferred to both free trade or an export/import tax, at least in the short run, but only if all provinces and all softwood lumber products are included in the Agreement and a means for sharing the windfall rents can be found. For. Sci. 48(4):712–721.
Periodicity of Two-Year Cycle Spruce Budworm Outbreaks in Central British Columbia: A Dendro-Ecological Analysis
Authors: Zhang Qi-Bin , Alfaro René I. 
Published: April 2024

Abstract
An outbreak of the two-year cycle budworm (Choristoneura biennis Freeman) has caused defoliation damage to interior spruce (Picea engelmannii Parry × P. glauca (Moench)) and subalpine fir (Abies lasiocarpa [Hook.] Nutt.) forests of north central British Columbia for more than 10 yr and was ongoing in 1999. A sample of 429 increment cores from spruce, subalpine fir, and lodgepole pine (Pinus contorta var. latifolia Engelm.) was collected in areas of chronic defoliation, and used in a dendro-ecological study. The objective was to develop accurately dated ring-width chronologies of each species and, by comparing growth rates of the budworm host tree species (spruce and fir) with those of the nonhost pine, to determine the past history of budworm outbreaks in the region. This history would help in estimation of the potential duration and severity of the current outbreak in the region.Four periods of decade-long reduced growth attributable to budworm defoliation were identified in the increment cores from both spruce and subalpine fir. These occurred in the mid-1890s to the early 1900s, the mid-1920s to the mid-1930s, the 1950s to the early 1960s, and the late 1980s to present (1999). Outbreaks recurred approximately every 32 yr. The reduced growth period, indicative of past outbreaks, consisted of a growth reduction phase lasting 7 to 11 yr in which rings generally exhibited a pattern of alternating wide and narrow rings (a “saw-tooth” pattern). This pattern was attributed to the biennial nature of the life cycle of this budworm, in which severe damage is caused every other year. The growth reduction phase was followed by a growth recovery phase lasting 3 to 5 yr in which ring-width gradually returned to pre-outbreak levels. Thus, the entire growth loss period could last from 10 to 16 yr and cause an average annual loss in radial increment from 16 to 21%. The 32 yr cycle of outbreak recurrence was attributed to changes in forest structure in which the forest evolves from a nonsusceptible to a susceptible state as the proportion of subalpine fir present in the upper canopy increases relative to the spruce component. A 2 yr cycle budworm outbreak will selectively remove the subalpine fir component returning the forest to a less susceptible state. It was concluded that the 2 yr cycle budworm is an important disturbance agent of northern British Columbia forests causing significant growth loss. FOR. SCI. 48(4):722–731.
Potential Demand for Certified Wood Products in the United Kingdom and Norway
Authors: Veisten Knut 
Published: April 2024

Abstract
Representative samples of the British and Norwegian population were surveyed by telephone and asked to make a hypothetical choice between unlabeled wooden furniture and more expensive eco-labeled wooden furniture. Choice behavior was modeled as a random utility model with utility-theoretic restrictions on choice and estimated willingness to pay (WTP). To counteract upward biased hypothetical values, a followup question assessed the certainty of respondents' choices. For those not choosing the eco-labeled alternative, another followup question assessed if these individuals could be regarded as indifferent.Compared to the unlabeled wooden furniture with a price of US$332 in the UK and US$275 in Norway, the extra median WTP for the eco-labeled alternative was estimated to be US$5.16 (1.6%) in the UK and US$2.79 (1%) in Norway, with a censored log-logistic binary choice model. In these estimates only the “absolutely sure ” were counted as valid choices of the eco-labeled alternative. The censoring implied that those who indicated indifference between unlabeled and eco-labeled furniture had their estimated WTP adjusted to 0. About 39% of the UK population and 32% of the Norwegian population are predicted to choose the eco-labeled alternative when the price difference is less than 5%. FOR. SCI. 48(4):767–778.
Effects of Registration Errors Between Remotely Sensed and Ground Data on Estimators of Forest Area
Authors: Patterson Paul L. , Williams Michael S. 
Published: April 2024

Abstract
The estimation of area by land cover type is a key component of most large-scale forest inventories. Historically, these estimates were derived from a large sample of points, taken from aerial photos, followed by a smaller sample of ground points, which were used to correct errors in the classification of the aerial photo points. There has been interest in replacing aerial photography with satellite imagery. One problem with using satellite imagery is the registration errors between a pixel and a plot or a point on the ground. The estimators and modes of inference can differ substantially depending on whether the sample unit is a plot or point on the ground. Two terms, tessellated and point paradigm, are used to differentiate between the two approaches when the ground data consists of plots or points, respectively. The effects of registration errors are compared using the two paradigms for estimating the area of land by cover type. The effects of registration errors on the expected value and variance of the forest area estimator under both the tessellated and point paradigm were studied using a simulation study, where a percentage of the samples had a random one- or two-pixel registration error. The simulation study shows that registration errors increased the variance of the estimator of forest area from 4% to 434%. The estimator of forest area under both the tessellated and point paradigm exhibited no detectable bias. In the presence of registration errors, the estimated variance under the tessellated paradigm tended to overestimate the true variance with the achieved coverage rate for a nominal 80% confidence interval ranging from about 81% to 86%. For sample sizes of fewer than 100 ground points, the estimated variance under the point paradigm tended to underestimate both the 80% confidence interval and the true variance, regardless of whether there were registration errors. Further testing showed that sample sizes of between 100 and 250 ground points were needed before the estimator of the variance under the point paradigm converged to within 5% of the true variance of the estimator of forest area. Thus, we conclude that registration errors can drastically increase the variance of area estimators and the resulting confidence intervals will not achieve their nominal coverage rates. In this study, the forest area estimator under the tessellated paradigm was clearly more robust to registration errors than the area estimator under the point paradigm. FOR. SCI. 49(1):110–118.
Production Efficiency and Productivity Growth in Norwegian Sawmilling
Authors: Nyrud Anders Q. , Baardsen Sjur 
Published: April 2024

Abstract
Production efficiency of Norwegian sawmilling was examined using Data Envelopment Analysis. The analysis was carried out on an extensive panel data set, including about 200 sawmills during the period 1974 to 1991. Productivity growth throughout the period was investigated using the Malmquist productivity index. The results indicate that approximately 30% of the sawmills were producing efficiently when assuming constant returns to scale. Estimated production growth approximated 1% per year. FOR. SCI. 49(1):89–97.
Scaling Growth Relationships from Seedling Plots Using Similarity Analysis
Authors: Amateis Ralph L. , Sharma Mahadev , Burkhart Harold E. 
Published: April 2024

Abstract
Data from a small-scale loblolly pine seedling experiment established at 1/16 scale to an operational study were used to develop height and diameter development models appropriate for either scale. An additional model was constructed that analytically relates stand development between the two scales and links the size of trees grown at small scale to operational scale counterparts. Results suggest that important stand characteristics associated with forest productivity develop similarly at the two scales. The models presented here can be used to evaluate the effects of stand density on tree growth at either scale and make inferences to operational scales from small-scale seedling studies. FOR. SCI. 49(2):188–195.
Inherent Correlations Between Stand Biomass Variables Calculated from Tree Measurements
Authors: Dean Thomas J. , Cao Quang V. 
Published: April 2024

Abstract
Correlating stand-level variables is an important component of forest production ecology; however, correlations among variables calculated with equations having common independent variables are potentially spurious. Monte Carlo simulation techniques were used to determine the inherent or null correlation coefficients among stand-level biomass variables calculated with published, individual-tree equations using loblolly pine (Pinus taeda L.) data. Null correlations of foliage mass/ha with branch mass/ha, stem mass/ha, and periodic annual increments of biomass were high with similar equation forms and exponents in the equations. Most, but not all, correlation coefficients of foliage mass/ha with other biomass components and periodic annual increments of biomass were significantly different from the corresponding, null correlation coefficients. Stating the probability of a greater difference between the observed and the null correlation coefficients proved crucial in distinguishing between potentially meaningful and spurious correlations because in many cases, the observed correlation coefficients were close to the null values. Interpretation of the correlations among stand variables varied with the equations used to predict the variables. Consequently, in addition to comparing correlation coefficients to appropriate null values, conclusions drawn from the correlation among stand-level variables depend on the accuracy and precision of the equations used to calculate them. FOR. SCI. 49(2):279–284.
A Reformulation of the Cost Plus Net Value Change (C+NVC) Model of Wildfire Economics
Authors: Donovan Geoffrey H. , Rideout Douglas B. 
Published: April 2024

Abstract
The Cost plus Net Value Change (C+NVC) model provides the theoretical foundation for wildland fire economics and provides the basis for the National Fire Management Analysis System (NFMAS). The C+NVC model is based on the earlier least Cost plus Loss model (LC+L) expressed by Sparhawk (1925). Mathematical and graphical analysis of the LC+L model illustrates two errors in model formulation. First, suppression is incorrectly modeled as a model output. Second, suppression and primary protection are incorrectly modeled as negatively correlated. These errors are shown to be perpetuated by the contemporary C+NVC model and to have serious implications for the model's capacity to correctly identify the most efficient level of fire management expenditure. A corrected graphical representation of the C+NVC model is presented, which allows the most efficient level of fire management expenditure to be correctly identified. FOR. SCI. 49(2):318–323.
Selecting a Level of Conditioning for the Segmented Polynomial Taper Equation
Authors: Sharma Mahadev , Burkhart Harold E. 
Published: April 2024

Abstract
Using tree data collected from loblolly pine thinning study plots, different levels of conditioning were examined for the segmented polynomial taper equation presented by Max and Burkhart (1976). An eight-parameter model with minimum constraints (diameter at the tip of a tree is zero and the adjacent functions are continuous at the join points) did not perform better than a six-parameter model with an additional smoothness constraint in terms of fit and predictive ability.
The join points where the adjacent segments of a tree meet, the inflection points, were assumed known to further reduce the number of parameters in the model. A four-parameter model with inflection points at 11 and 75% of total tree height was slightly superior to the six- and eight-parameter models in estimating tree diameters. The fit statistics and predictive ability of the model were not sensitive to the lower and upper inflection points in the range of 9–12% and 70–80%, respectively. For. Sci. 49(2):324–330.
Modeling Tree Mortality Following Wildfire in the Southeastern Canadian Mixed-Wood Boreal Forest
Authors: Hély Christelle , Flannigan Mike , Bergeron Yves 
Published: April 2024

Abstract
We modeled tree mortality three months after a wildfire in the mixed-wood boreal forest (Quebec, Canada) using data from 1963 trees in 36 stands burned under a wide range of fire behavior conditions during the 1997 Val Paradis fire. Stand composition influenced the char height: height of burn was lower in deciduous stands than mixed or coniferous stands. Analysis of species mortality rates revealed that Populus tremuloides Michx. was the least fire-resistant species, whereas Picea mariana Moench and Pinus banksiana Lamb. were the most resistant species. Efficient interactions for conifers exist between crown and cambial resistance to injury and fire behavior, as diameter at breast height (DBH), total tree height (TOTH), and mean bark thickness are characteristic variables throughout the fire behavior range. The best logistic regressions, relating probability of wildfire-induced mortality to morphology and fire variables, always entered char height (CH) at the first step of the stepwise procedure, followed by a morphological variable (DBH or TOTH). The Kappa coefficient used for model validations revealed that logistic regressions using morphologic and fire variables were very efficient as compared to logistic regressions based only on morphologic variables. Potential applications of these results by land managers are discussed. FOR. SCI. 49(4):566–576.
Efficiency and Merger Gains in the Danish Forestry Extension Service
Authors: Bogetoft Peter , Thorsen Bo Jellesmark , Strange Niels 
Published: April 2024

Abstract
In Denmark, many small-scale forest owners are affiliated to local district offices of The Danish Forestry Extension Service. In this article, the efficiency of the different offices is evaluated using Data Envelopment Analysis (DEA). Furthermore, recent theoretical developments in DEA are used to assess the gains from a number of potential mergers and to decompose these gains into those from technological improvements, harmony effects, and scale effects. The results show that inefficiency is widespread and may in some cases be improved through mergers due to potential harmony gains and scale returns. However, the dominant part of the inefficiency is technical, and this suggests that improved learning and sharing of know-how or key resources across offices may improve efficiency. For. Sci. 49(4):585–595.
Book Reviews: Forest Policy for Private Forestry—Global and Regional Challenges
Authors: Bentley William R. 
Published: April 2024

Abstract
This volume is a collection of the best papers presented during a 2001 international conference in Atlanta titled Global Initiatives and Public Policies: First International Conference on Private Forestry in the 21st Century. The papers are grouped in four sections, with the broadest views in the first and most detailed in the last two sections.
Book Reviews: The Potential of U.S. Forest Soils to Sequester Carbon and Mitigate the Greenhouse Effect
Authors: Jose S. 
Published: April 2024

Abstract
In recent years, the growing realization that as much as 40–60% of the carbon in forest ecosystems is stored belowground has sparked a great deal of interest in exploring forest soil processes and their relation to carbon dynamics. Because of its slower turnover rates, soil organic carbon offers considerable potential to mitigate the increase in atmospheric carbon dioxide and alleviate the greenhouse effect. Through the publication of this book, the editors have done a remarkable job in bringing together the collective wisdom of 41 prominent soil scientists in analyzing the carbon sequestration potential of U.S. forest soils and the implications for policy decisions. This book is the third one in a series of books addressing the carbon sequestration potential of U.S. land use systems. The first two books examined the potential of crop and grazing lands and were published in 1999 and 2001, respectively.
Light Transmittance Estimates in a Longleaf Pine Woodland
Authors: Battaglia Michael A. , Mitchell Robert J. , Mou Paul P. , Pecot Stephen D. 
Published: April 2024

Abstract
While the importance of canopy structure in open woodlands and savannas on regulating the flow of energy and matter is well known, few studies have investigated how variation in overstory abundance influences canopy light transmission and the extent that estimates vary in their ability to characterize the light environment in these ecosystems. Canopy light transmittance (% photosynthetic photon flux density, or %PPFD) was measured with gallium arsenide phosphide (GaAsP) photodiodes and was monitored throughout the growing season in an open-canopy longleaf pine (Pinus palustris Mill.) woodland across an overstory abundance gradient. Several estimates of canopy light transmittance were also measured, including 10 minute averages of %PPFD under clear and overcast sky conditions during summer, fall, and winter, as well as light estimates derived from hemispherical photographs (gap fraction, GF: gap light index, GLI; and weighted canopy openness, WCO). Linear and curvilinear regression were used to analyze the relationship between (1) light measurements and canopy structure and (2) light estimates and growing-season % PPFD measured by light diodes. Of all light measurements in this study, ten-minute average % PPFD measurements during clear days were the most variable: only a small proportion in the 10-minute average of light reaching the understory was correlated to either overstory structure or growing-season canopy transmittance. While measures on overcast days improved the correlations, they tended to overestimate transmittance. Gap fraction (GF) and gap light index (GLI) were strongly correlated with % PPFD and overstory structure, and the relationship between GLI and % PPFD was improved by using a direct light setting of 60%. In addition to strong correlation, hemispherical photographic estimates of light fell along a 1:1 line with % growing-season PPFD; thus, estimates were relatively unbiased. Measures of light in this ecosystem need to incorporate the large spatial and temporal variation in light transmittance that is characteristic of this ecosystem if investigators are to understand the relationship between open-canopy woodlands and their light environments.