bluuebunny/crossref_metadata_2025 huggingface dataset:
Restoration Treatment Effects on Stand Structure, Tree Growth, and Fire Hazard in a Ponderosa Pine/Douglas-Fir Forest in Montana
Authors: Fiedler Carl E. , Metlen Kerry L. , Dodson Erich K.
Published: April 2024

Crown fires that burned thousands of ha of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) forests in recent years attest to the hazardous conditions extant on the western landscape. Managers have responded with broad-scale implementation of fuel reduction treatments; however. because threats to pine forests extend beyond fire, so too must the approaches to address them. This western Montana study evaluated four treatments in a randomized complete block experiment for their effects on stand structural characteristics, growth increment, and crown fire potential. Evaluation of control, burn-only, thin-only, and thin-burn treatments showed that the combined thin-burn treatment had the greatest number of desired effects, the burn-only had the fewest, and the thin-only was intermediate. The thin-burn significantly reduced stand density, canopy cover, torching hazard, and crowning hazard and increased average diameter, height-to live-crown, and basal area increment; the thin-only reduced stand density, canopy cover, and crowning hazard and increased average diameter and basal area increment; and the burn-only reduced torching hazard and increased height-to-live crown. These structural and growth effects are related to or influence numerous stand/ecosystem properties at our site, including diameter distributions, species composition, large-tree development potential, overall tree vigor, potential for shade-intolerant tree regeneration, and resiliency to fire. Results demonstrate that well-designed restoration treatments can promote key short-term stand and ecosystem responses while significantly reducing crown fire potential.
Fuels and Predicted Fire Behavior in the Southern Appalachian Mountains After Fire and Fire Surrogate Treatments
Authors: Waldrop Thomas , Phillips Ross A. , Simon Dean A.
Published: April 2024

This study tested the success of fuel reduction treatments for mitigating wildfire behavior in an area that has had little previous research on fire, the southern Appalachian Mountains. A secondary objective of treatments was to restore the community to an open woodland condition. Three blocks of four treatments were installed in a mature hardwood forest in western North Carolina. Fuel reduction treatments included chainsaw felling of small trees and shrubs (mechanical treatment), two prescribed fires 3 years apart, a combination of mechanical and burning treatments, and an untreated control. Mechanical treatment eliminated vertical fuels but without prescribed burning; the mechanical treatment added litter (11%) and woody fuels (1 hour 167%; 10 hours 78%) that increased several measures of BehavePlus4-simulated fire behavior (rate of spread, flame length, spread distance, and area burned) for 5 years. Prescribed burning reduced litter mass by 80% and reduced all simulated fire behavior variables for 1 year but had no residual effect by the third year. The combined mechanical and burning treatments had hot prescribed fires (mean temperature of 517°C at 30 cm aboveground) during the first burn that killed some overstory trees, resulting in increased amounts of woody fuels on the forest floor. All active treatments (fire, mechanical, and combined) reduced simulated wildfire behavior, even after a severe ice storm that added fine fuels. Prescribed burning in combination with the mechanical treatment was the most effective in reducing all measures of fire behavior and advancing restoration objectives. Each of the active treatments tested must be repeated to reduce fuels and lower wildfire behavior, but prescribed burning must be repeated frequently.
Influence of Crown Biomass Estimators and Distribution on Canopy Fuel Characteristics in Ponderosa Pine Stands of the Black Hills
Authors: Keyser Tara , Smith Frederick W.
Published: April 2024

Two determinants of crown fire hazard are canopy bulk density (CBD) and canopy base height (CBH). The Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) is a model that predicts CBD and CBH. Currently, FFE-FVS accounts for neither geographic variation in tree allometries nor the nonuniform distribution of crown mass when one is estimating CBH and CBD. We develop allometric equations specific to ponderosa pine (Pinus ponderosa Dougl. ex Laws.) in the Black Hills to predict crown mass and use the Weibull distribution to model the vertical distribution of crown mass within individual trees. We present parameter prediction models that, in turn, predict the vertical distribution of crown mass based on stand- and tree-level attributes. With use of an FFE-FVS executable incorporating local crown mass equations and the parameter prediction models, new estimates of CBD and CBH were produced. Locally derived biomass equations predicted substantially greater estimates of foliage mass than currently predicted by FFE-FVS. The increase in CBD resulting from the local biomass and vertical distribution models averaged 78% over original estimates. Our results suggest that locally derived crown mass equations in addition to nonuniform estimates of crown mass distribution be used to calculate CBH and CBD as used in fire prediction models.
Net Benefits of Wildfire Prevention Education Efforts
Authors: Prestemon Jeffrey P. , Butry David T. , Abt Karen L. , Sutphen Ronda
Published: April 2024

Wildfire prevention education efforts involve a variety of methods, including airing public service announcements, distributing brochures, and making presentations, which are intended to reduce the occurrence of certain kinds of wildfires. A Poisson model of preventable Florida wildfires from 2002 to 2007 by fire management region was developed. Controlling for potential simultaneity biases, this model indicated that wildfire prevention education efforts have statistically significant and negative effects on the numbers of wildfires ignited by debris burning, campfire escapes, smoking, and children. Evaluating the expected reductions in wildfire damages given a change in wildfire prevention education efforts from current levels showed that marginal benefits exceed marginal costs statewide by an average of 35-fold. The benefits exceeded costs in the fire management regions by 10- to 99-fold, depending on assumptions about how wildfire prevention education spending is allocated to these regions.
Forestry Practices and Veneer Log Value—Manufacturer's Assessments of Veneer Log Attributes
Authors: Alderman Delton R. , Brinberg David , Wiedenbeck Jan
Published: April 2024

Hardwood veneer logs comprise less than 1% of the eastern hardwood forest resource in the United States; yet the typical range for veneer log prices is 2–10 times greater than that of grade 1 sawlogs. In this article we examine attributes and defects known to affect the value of veneer logs and shed light on forest management considerations that affect veneer log production. Veneer attribute data were collected for black cherry (Prunus serotina Ehrh.), black walnut (Juglans nigra L.), northern red oak (Quercus rubra L.), sugar maple (Acer saccharum Marsh.), and white oak (Quercus alba L.). Social judgment theory was used to assess veneer attributes and defects. Color (hue and consistency) and rings (density and texture) are the drivers in veneer log selection, and the results are also indicated by a “Species by Color” interaction and a “Species by Rings” interaction. Other cues are important but do not appear to drive log selection. Hardwood forest management practices, in which partial cuttings are performed, can affect the potential product value of face veneer quality residual stems by changing the rate of diameter growth.
Genetic Contributions to Phenotypic Variation in Physiology, Growth, and Vigor of Western Aspen (Populus tremuloides) Clones
Authors: Clair Samuel B. St. , Mock Karen E. , LaMalfa Eric M. , Campbell Robert B. , Ryel Ronald J.
Published: April 2024

In aspen and other plant species the effects of environment on phenotype are generally better characterized than genotypic influences. Furthermore, little is known about how genetic influences on tree phenotype change over time. We assessed clonal differences in 417 ramets, representing 18 clones, in a common garden of quaking aspen (Populus tremuloides Michx.) that have developed over 27 years. Genetic contributions to variation in physiology, growth, and vigor were determined over seasonal and multidecadal time scales. The 18 aspen clones exhibited wide-ranging phenotypic variation with two- to threefold differences in physiology and growth traits and more than sevenfold differences in canopy decline and mortality. For growth traits, strong genetic correlations (typically greater than 0.70) and heritability (estimates maintained in a range of 0.25 to 0.36), indicate that genotype had a moderate and consistent influence on growth over the three decades of the study. Physiological traits had much lower genetic correlations and heritability estimates, and they changed significantly within a single growing season. Climatic data suggest that dry conditions in the common garden as the summer progressed may have had a controlling influence on physiological trait responses. Characterizing genetically based phenotypic variation and how it contributes to clone vigor provides a critical link to understanding constraints to aspen viability in its western range.
Estimating Individual Stand Size–Density Trajectories and a Maximum Size–Density Relationship Species Boundary Line Slope
Authors: VanderSchaaf Curtis L.
Published: April 2024

Understanding self-thinning patterns of a species helps resource managers make decisions about proper planting densities and timings of thinnings. It is generally assumed that size–density trajectories of even-aged, monospecific, self-thinning stands consist of three phases: first, a curved approach to a linear portion that represents moderate rates of intraspecific mortality; second, a linear portion where tree density/ha (N) is at its maximum for a particular quadratic mean diameter (Dq), often termed the maximum size–density relationship (MSDR) dynamic thinning line; and third, a divergence from the linear portion. In this article, segmented regression was used to determine what observations are within various phases of self-thinning for a loblolly pine (Pinus taeda L.) planting density trial located in central Mississippi. Those observations estimated to be within the MSDR dynamic thinning line phase of individual plots were combined to estimate a MSDR species boundary line slope (−1.640) using a linear mixed-effects model approach. Based on the N and Dq, where the MSDR dynamic thinning line phase was estimated to begin using segmented regression analyses, and the estimated MSDR species boundary line slope of −1.640, planting density-specific maximum values of Reineke's stand density index were predicted.
Using Linear Mixed Effects in Helicopter Logging Data
Authors: Lyons Kevin , Xing Li , Nelson John D.
Published: April 2024

This article applies a linear mixed-effects model (LME) to an unpublished helicopter logging productivity data set. The data were clustered in units, and the silviculture treatments varied between units, where units are cutblocks. When the covariance matrix was considered, it was found that the interunit variance was significant and the intraunit variance was heterogeneous. The significant interunit variance results in significant intraunit correlation, and this indicates the need to use LME to analyze these data. When turn time was considered, unit 4, which had the lowest level of group retention, had a conditional predicted value that was significantly less than the marginal predicted value. When turn weight was considered, unit 2, which had small patch cuts, had a conditional predicted value that was significantly less than the marginal predicted value, and unit 4 had a conditional predicted value that was significantly higher than the marginal predicted value. When productivity was considered, the conditional predicted value for unit 4 was significantly greater than the marginal predicted value, and unit 2 was significantly less than the marginal predicted value. In this data set it is interesting to note that productivity is independent of the number of logs in a turn and that turn weight was relatively insensitive to the available explanatory variables.
A New Look at Spread Rates of Exotic Diseases in North American Forests
Authors: Evans Alexander M. , Finkral Alex J.
Published: April 2024

Exotic pathogens threaten ecosystems in novel ways, particularly where they are facilitated by stresses such as climate change and forest fragmentation. Although chestnut blight (CB), Dutch elm disease (DED), beech bark disease (BBD), and white pine blister rust (WPBR) are well-studied pathogens, this investigation is the first to provide estimated rates of spread based on an expansive geospatial database and a consistent, rigorous analytical framework. We use quantile regression to analyze 850 records of infection over the last (20th) century. The results show that in the past, forest disease complexes have spread at rates between 7.4 and 31 km year−1, and two-thirds of the estimates were less than 17 km year−1. We estimated the spread of CB at 31 km year−1, DED in eastern North America at 25 km year−1, DED in western North America at 14 km year−1, BBD at 16 km year−1, WPBR in eastern North America at 7.4 km year−1, and WPBR in western North America at 10 km year−1. These results do not predict the rate of spread of future exotic pathogens in North American forests; rather they provide context for predictive models and a heuristic guide until more scientific data are available.
Valuation of Timber Harvest Contracts as American Call Options with Modified Least-Squares Monte Carlo Algorithm
Authors: Petrasek Stanislav , Perez-Garcia John M.
Published: April 2024

This article presents a Monte Carlo methodology for the valuation of timber harvest contracts in the presence of stochastic timber prices, flexibility in harvest timing, and penalty clauses. Harvest contracts are treated as American call options on the value of timber. The modifications to the least-squares Monte Carlo algorithm necessary to incorporate penalty clauses are presented. The application of the proposed methodology is then demonstrated on a valuation problem characteristic of harvest contracts sold by the Washington Department of Natural Resources.
Evaluation of Parameter Estimation Methods for Fitting Spatial Regression Models
Authors: Lu Junfeng , Zhang Lianjun
Published: April 2024

Two types of spatial regression models, a spatial lag model (SLM) and a spatial error model (SEM), were applied to fit the height-diameter relationship of trees. SEM had better model fitting and performance than both SLM and ordinary least squares. Moran's I coefficients showed that SEM effectively reduced the spatial autocorrelation in the model residuals. Both real data and Monte Carlo simulations were used to compare different parameter estimation methods for the two spatial regression models, including maximum likelihood estimation (MLE), Bayesian methods, two-stage least squares (for SLM) and generalized method of moments (GMM) (for SEM). Our results indicated that GMM was close to MLE in terms of model fitting, much easier in computation, and robust to non-normality and outliers. The Bayesian method with heteroscedasticity did not effectively estimate the spatial autoregressive parameters but produced very small biases for the regression coefficients of the model when few outliers existed.
Measuring the Value of Information in Multicriteria Decisionmaking
Authors: Kangas Annika S. , Horne Paula , Leskinen Pekka
Published: April 2024

Decisions in forestry typically include uncertainty. The decisionmaker then has two options: either to make the optimal choice between different alternative actions with the current information or to try to reduce the uncertainty by collecting more information. The value of information is due to the ability to make better decisions with new information. When the decisions only affect provision of goods that have market value, evaluation of alternative decisions is in principle a straightforward exercise of cost-benefit analysis. In sustainable forest management, however, multiple objectives typically exist, and these objectives may be related to provision of public goods and services. Because such goods and services cannot be directly measured in monetary terms, the problem of value of information is more complicated. The possible solutions are to assess the monetary value separately for all goods and services and evaluate the decisions with cost-benefit analysis or to evaluate the decisions in terms of utility with multicriteria analysis and calculate the (monetary) value of decisions based on these utilities. The aim of this study was to present these two cases for evaluating decisions and analyze their similarities and differences and to discuss the usefulness of these approaches in evaluating the value of information from different perspectives.
Stabilized Soil Organic Carbon Pools in Subsoils under Forest Are Potential Sinks for Atmospheric CO2
Authors: Lorenz Klaus , Lal Rattan , Shipitalo Martin J.
Published: April 2024

The soil organic carbon (SOC) pool stored in subsoil horizons in forests plays an important role in the global carbon cycle. Strategies are needed to increase the subsoil SOC pool in forests because the turnover time of SOC increases with increase in soil depth as subsoil SOC is chemically and physically stabilized. We compared the total SOC and total nitrogen (TN) pools, chemically and physically separated SOC fractions, and C and N pools in fine roots in a soil pedon in an oak-hickory forest type consisting of white oak (Quercus alba L.) and red oak (Quercus rubra L.) with yellow-poplar (Liriodendron tulipifera L.) at the North Appalachian Experimental Watershed near Coshocton, Ohio, USA. The SOC pool was the highest in the A horizon (47.4 Mg ha−1) and smaller in the Bt1 (6.9 Mg ha−1) and Bt2 (6.7 Mg ha−1) horizons. The SOC and TN concentrations sharply decreased with depth. Fine root C and N pools were much larger in the A horizon (0.71 and 0.025 Mg ha−1) than in underlying horizons. Although only 22% of the SOC pool was stored below the A horizon, 58% of the chemically stabilized and 31% of the physically stabilized SOC fractions pool occurred in the subsoil horizons. Thus, studies are needed to test whether forest management can increase the stabilized SOC pool in subsoil horizons to mitigate the human-induced climate change.
Initial Response of Soil Carbon and Nitrogen to Harvest Intensity and Competing Vegetation Control in Douglas-Fir (Pseudotsuga menziesii) Plantations of the Pacific Northwest
Authors: Slesak Robert A. , Schoenholtz Stephen H. , Harrington Timothy B. , Meehan Nathan A.
Published: April 2024

We assessed the effect of harvest type (bole-only or whole-tree) and vegetation control treatments (initial or annual application of herbicide) on soil C and N at two contrasting sites in the Pacific Northwest. Pretreatment (2003) and posttreatment (2005) soil samples were collected by depth to 60 cm, and a stratified sampling approach based on four surface conditions was used for posttreatment sampling in surface soils. Surface condition had a significant effect on soil C and N concentrations, generally decreasing with decreasing amounts of logging debris and increasing soil disturbance. There was no difference between harvest treatments in the change in soil C and N content despite differences in surface condition coverage between harvest types, indicating estimates of C and N change determined from the stratification approach were imprecise. Soil C and N content tended to increase regardless of treatment, but increases were significant only in the bole-only harvest at one site and in the whole-tree harvest at the other site. Initial vegetation control caused significantly greater positive change in soil C and N than the annual vegetation control treatment, with effects limited to surface soil at one site and all sample depths at the other site. Much of these increases occurred in deeper (>20 cm) parts of the soil profile, indicating that deep soil sampling is necessary for assessment of harvest-related change in soil C and N.
The Use of Ground-Penetrating Radar to Accurately Estimate Soil Depth in Rocky Forest Soils
Authors: Sucre Eric B. , Tuttle John W. , Fox Thomas R.
Published: April 2024

Ground-penetrating radar (GPR) is a geophysical tool that has the capability, given favorable soil properties, to improve the accuracy of soil depth estimation, compared with other commonly used methods. This study was conducted on three different physiographic regions across the southern Appalachian Mountains: the Ridge and Valley (n = 9), Cumberland Plateau (n = 6), and Allegheny Plateau (n = 6). At each site (n = 21), a 20- × 20-m measurement plot was scanned using both 200- and 400-MHz antennas to estimate average soil depth. Soil depth estimates obtained from both GPR antennas were compared with each other as well as with soil depth estimations obtained with a soil auger using a paired t test (α = 0.05). No significant differences in soil depth were observed for the 200- versus 400-MHz antennas (P = 0.913). Consequently, data recorded from the 400-MHz antenna were used when depth measurements between the GPR and soil auger were compared. This was done because of the smaller and lighter antenna size and better practicality (i.e., can be used by a single operator) compared with the heavier and bulky 200-MHz antenna. Across all plots (n = 21), depth estimations were shallower using a soil auger compared with estimates obtained using GPR across all plots (P = 0.0002). Results from this study demonstrate how current methods can underestimate soil depth in rocky forest soils. Depth estimations from GPR could be used to more accurately quantify site quality in the southern Appalachians by providing the precise data needed to calculate nutrient availability and water-holding capacity. Last, the reduction in size and weight of GPR antennas and computers now provides forest scientists a practical and powerful technology that should be revisited because it has been confined to very specific applications over the last 25 years.
Estimating a Multilevel Dominant Height–Age Model from Nested Data with Generalized Errors
Authors: Yang Yuqing , Huang Shongming
Published: April 2024

A dominant height-age model was developed following a multilevel nonlinear mixed-model approach. Random effects were modeled at the plot and the tree levels, with two random parameters at each level. In addition to the random effects, a variance function was used to model heteroscedasticity, and various covariance structures were evaluated to account for residual autocorrelation. A new covariance structure, the modified spatial power structure, is proposed. This new structure was found to provide the best fit to the model. Although residual autocorrelations were still not completely removed by this structure, they were substantially reduced. Model validation results using an independent data set confirmed that the final model with the modified spatial power structure produced more accurate and precise dominant height predictions. This was true for both expansion methods, and the empirical best linear unbiased predictor (EBLUP) expansion showed better results than the ZERO expansion. The model with the modified spatial power structure fitted by the EBLUP expansion method, therefore, was chosen as the preferred model for making tree-specific, dominant height predictions. The advantages and relevance of the multilevel nonlinear mixed-model approach for forest growth and yield modeling are discussed.
Improving Tree Age Estimates Derived from Increment Cores: A Case Study of Red Pine
Authors: Fraver Shawn , Bradford John B. , Palik Brian J.
Published: April 2024

Accurate tree ages are critical to a range of forestry and ecological studies. However, ring counts from increment cores, if not corrected for the years between the root collar and coring height, can produce sizeable age errors. The magnitude of errors is influenced by both the height at which the core is extracted and the growth rate. We destructively sampled saplings and small trees of red pine (Pinus resinosa Ait.) and combined within- and between-tree cross-dating to determine accurate rings counts and radial growth rates for 11 stem sections of each sample. We developed regression models to estimate age adjustment as a function of coring height and radial growth rate. We compared candidate models using corrected Akaike's information criterion scores, and we evaluated model performance by jackknife permutations. Application of our best-fit equations clearly improved age estimates: compared with unadjusted ring counts, our adjusted age estimates had normally distributed errors centered near 0, lower standard deviations, and a narrower range of values. Thus, these equations can be used to adjust ages of cored, mature trees occurring in these same settings. The methods used here may be applied to other shade-intolerant or mid-tolerant species where improved tree establishment dates are needed.
Modeling Jack Pine (Pinus banksiana) Foliage Density Distribution
Authors: Schneider Robert , Fortin Mathieu , Berninger Frank , Ung Chhun-Huor , Swift D. Edwin , Zhang S.Y.
Published: April 2024

The vertical distribution of foliage biomass is important because it is associated with photosynthesis and is closely related to some wood quality attributes such as branch diameter and sapwood content. In this article we propose a model to predict foliage biomass distribution within the crown for jack pine trees in Eastern Canada. This model has two parts. The first one distinguishes the proportion of nodal (formed at the end of each yearly shoot) and internodal (formed during the growing season) foliage biomass. The second part of the model predicts the distribution of the biomass depending on the type of foliage (nodal or internodal). This second part is based on a two-parameter beta cumulative distribution function (cdf). The parameterization of this cdf was performed using a mixed-effects nonlinear regression. The proportion of foliage biomass found in the nodal whorls is proportional to dbh and age and inversely proportional to total height. The distribution of the foliage biomass in the nodal whorls is dependent only on tree-level variables whereas the internodal foliage biomass is influenced by both tree- and stand-level variables. The internodal foliage biomass maximum is closer to the crown base than that of nodal foliage biomass. Decomposing the distribution into whorl types leads to a better description of crown characteristics.
A Parsimonious Dynamic Stand Model for Interior Spruce in British Columbia
Authors: García Oscar
Published: April 2024

A whole-stand growth model, Scube, was developed for spruce-dominated, even-aged, natural and planted stands, using permanent sample plot data from the sub-boreal spruce biogeoclimatic zone of British Columbia, Canada. Available data were limited, with no information on mature planted stands or thinning treatments. A parsimonious model design, incorporating knowledge of stand dynamics and experience from other forests, made possible a logical reproduction of observed behavior and plausible extrapolations to other conditions. Scube consists of a system of four differential equations, describing the evolution of four state variables: top height, trees per hectare, basal area, and a stand closure indicator. Concepts of closure and site occupancy drive the behavior of young stands and the response to thinning. Parameters were estimated through numerical optimization of several residual functions, reflecting different projection interval types and weighting strategies. Differences in estimates among the various criteria were small. Calculations are facilitated through expressions that remain invariant in the absence of disturbances. The methods generalize the algebraic difference approach and related forest modeling techniques, linking them to standard dynamical systems theory.
The Effects of Road Quality and Other Factors on Water-Based Recreation Demand in Northern Ontario, Canada
Authors: Hunt Len M. , Dyck Adam
Published: April 2024

Resource managers are often faced with difficult decisions regarding the management of unpaved roads in forested environments. These decisions are complicated by the lack of information about ways that people use roads for leisure activities such as outdoor recreation. In this study, we assessed how the quality of roads and trails affected the demand for water-based recreation in northern Ontario, Canada. To make this assessment, we tested and controlled for several other factors that might influence this demand. The results from a random-effects, negative binomial regression of traffic counts to water-based settings suggested that demand was higher when road quality to sites was better, sites were in close proximity to human settlements, and large-sized water bodies that held desirable fish species were available. Furthermore, demand was higher when weather was warmer and drier, when people had more leisure time (i.e., weekends, statutory holidays, and summer), when wind speeds were low on large-sized water bodies, and when fuel costs were lower. The relative effect of road quality on counts was strongest of all of these factors. In fact, moving from a trail to a medium- or high-quality road was predicted to increase demand for water-based recreation by more than 200%. By understanding this direct effect of road quality along with the importance of other factors for water-based recreation demand, resource managers can carefully plan all stages of road management (i.e., creation, maintenance, and closure/removal of roads) to either encourage or discourage use.
Testing for Nonlinear Spatial Integration in Roundwood Markets
Authors: Niquidet Kurt , Manley Bruce
Published: April 2024

Prior studies have frequently not supported spatial market integration and the law of one price in roundwood markets. However, these studies have relied on cointegration tests that have low power in the presence of nonlinearities. Roundwood markets may display these effects due to high transactions costs between regions. In this article, we revisited the question of spatial integration in roundwood markets by using tests that have no cointegration as a null hypothesis and threshold cointegration as an alternative. For testing, a dataset of monthly New Zealand roundwood prices from four regional markets over the period from January 1995 to April 2010 were used. Similar to standard linear cointegration tests, the null hypothesis of no cointegration could not be rejected for most of the regional price pairs. One interpretation is that regional markets are segregated. Another interpretation is that the power of these nonlinear tests, although an improvement over that of their linear counterparts, is still relatively low.
Effects of Stand and Inter-Specific Stocking on Maximizing Standing Tree Carbon Stocks in the Eastern United States
Authors: Woodall Christopher W. , D'Amato Anthony W. , Bradford John B. , Finley Andrew O.
Published: April 2024

There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a nationwide annual forest inventory, we quantified trends in standing tree C across a variety of species mixtures and stocking attributes for 24 of the most common tree species in the eastern United States. We found that as interspecific stocking decreased, such that the majority of stand stocking was in a single species, maximum live tree aboveground carbon (AGC) decreased by 33% in highly stocked stands across all study species. Maximum standing dead tree AGC was not correlated with stand stocking but instead was related to interspecific stocking with AGC storage being reduced by more than 50% as stands became progressively occupied by one tree species. Although the competitive interactions between individual species and/or functional groups (i.e., shade tolerance) can greatly complicate efforts to assess forest C storage opportunities, some basic tenets identified in this study may refine future research hypotheses and broadly identify species mixtures and associated stocking levels that may maximize AGC storage.
What Drives Daily Volatility in Lumber Futures Markets?
Authors: Karali Berna
Published: April 2024

Most financial asset returns exhibit volatility persistence. This article investigates this phenomenon in the context of daily returns in lumber futures markets. The volatility of lumber futures is found to vary with different phases of the United States-Canada softwood lumber trade dispute. Daily price volatility was the highest in the post-Softwood Lumber Agreement period (2001–2005), followed by the Softwood Lumber Agreement period (1996–2000) and the period with trade disputes and temporary tariffs (1992–1995). An inverse relationship between inventory levels and volatility is found. Further, the inventory effect on volatility varies across the different periods of the trade dispute. An inverse relation between time to delivery and volatility is also found. Moreover, it is shown that although volatility persistence exists in the lumber futures market, the time gap between the arrival of news to the markets and the delivery time of futures contracts is the fundamental variable in explaining volatility persistence.
Allometric Scaling of Large Branch Volume in Hardwood Trees in Michigan, USA: Implications for Aboveground Forest Carbon Stock Inventories
Authors: MacFarlane David W.
Published: April 2024

Allometric scaling of large branch volume (branches to a ≥9-cm top diameter outside of bark) was examined using data from hundreds of hardwood trees of 11 hardwood tree species across a range of sites in Michigan. The amount of large branch volume in hardwoods generally increased with tree size with most of it in first-order branches (off of the main stem), but there were trees as small as 35 cm that had third-order large branches in their crowns. To explore how branch volumes scaled with bole volume, large branch volume expansion factors (VEFs) were calculated and correlated with several stem, branch, and crown metrics. Tree dbh and height, respectively, were weakly correlated (r2 = 0.15) and uncorrelated with VEFs, but crown ratio and the diameter of the largest branch in the tree explained almost 50% of variation in VEFs across a range of tree species, sizes, and site conditions. Combining stem, crown, and branch measurements allowed for as much as 64% of variation in branch to bole volume scaling to be explained. For 9 of 11 species studied, species-specific models improved model fits compared with those for a species-composite model. Understanding branch to bole volume relationships could improve forest carbon inventories by reducing error in whole-tree volume estimation and by clarifying the amount of merchantable volumes in branches, and correlates of large branch VEFs might even serve as indicators of whole-tree wood density.
Carbon Credit Eligibility under Area Regulation of Harvest Levels in Northern Minnesota
Authors: Gunn John S. , Saah David S. , Fernholz Kathryn , Ganz David J.
Published: April 2024

We evaluated the implications of area regulation of harvest on eligible carbon under both the Voluntary Carbon Standard (VCS) and the Chicago Climate Exchange (CCX) for public forest lands in north central Minnesota (89,840 ha total). We used data from the carbon submodel of the US Forest Service Forest Vegetation Simulator (Lake States variant) to evaluate changes in forest carbon stocks under different management scenarios. Baseline harvest intensity was defined by considering the manager's short-range tactical plans and the distribution of harvests by cover type and intensity class then became the “business as usual” (BAU) for use in the calculation of eligible carbon under the VCS and CCX. Under VCS, the most effective way to increase carbon stocks while meeting other management objectives was to shift harvest practices to lower intensity entries and retain higher residual basal areas. The carbon stock change rates for each manager varied significantly under the BAU scenario and resulted in a mean annual net decrease. Because CCX carbon credit eligibility requires a net increase of carbon stocking from the base year, area regulation may create periods of time where there is no eligible carbon volume. An alternate management strategy that uses the area regulation method, reduces harvest intensity, and decreases overall acreage harvested was able to provide higher postharvest carbon stocks versus the BAU scenario under VCS.
Late-Successional Biomass Development in Northern Hardwood-Conifer Forests of the Northeastern United States
Authors: Keeton William S. , Whitman Andrew A. , McGee Gregory C. , Goodale Christine L.
Published: April 2024

Managing the contribution of forest ecosystems to global carbon cycles requires accurate predictions of biomass dynamics in relation to stand development. Our study evaluated competing hypotheses regarding late-successional biomass dynamics in northern hardwood-conifer forests using a data set spanning the northeastern United States, including 48 mature and 46 old-growth stands. Continuous data on dominant tree ages were available for 29 of these and were used as an indicator of stand development. Aboveground live biomass was significantly (P < 0.001) different between mature (195 Mg/ha) and old-growth (266 Mg/ha) sites. Aboveground biomass was positively (P < 0.001) and logarithmically correlated with dominant tree age; this held for live trees (r2 = 0.52), standing dead trees (r2 = 0.36), total trees (r2 = 0.63), and downed woody debris (r2 = 0.24). In a Classification and Regression Tree analysis, stand age class was the strongest predictor of biomass, but ecoregion and percent conifer accounted for ∼25–33% of intraregional variability. Biomass approached maximum values in stands with dominant tree ages of ∼350–400 years. Our results support the hypothesis that aboveground biomass can accumulate very late into succession in northern hardwood-conifer forests, recognizing that early declines are also possible in secondary forests as reported previously. Empirical studies suggest a high degree of variability in biomass development pathways and these may differ from theoretical predictions. Primary forest systems, especially those prone to partial disturbances, may have different biomass dynamics compared with those of secondary forests. These differences have important implications for both the quantity and temporal dynamics of carbon storage in old-growth and recovering secondary forests.
Effects of Land Use/Cover Change and Harvests on Forest Carbon Dynamics in Northern States of the United States from Remote Sensing and Inventory Data: 1992–2001
Authors: Zheng Daolan , Heath Linda S. , Ducey Mark J. , Smith James E.
Published: April 2024

We examined spatial patterns of changes in forest area and nonsoil carbon (C) dynamics affected by land use/cover change (LUC) and harvests in 24 northern states of the United States using an integrated methodology combining remote sensing and ground inventory data between 1992 and 2001. We used the Retrofit Change Product from the Multi-Resolution Land Characteristics Consortium to quantify LUC. We then calculated C dynamics using C densities for major forest types based on US Forest Service Forest Inventory and Analysis data by forest area for different statuses (i.e., afforestation, deforestation, and forest remaining forest) and incorporated county-level harvest data. Across the region, 16,740 km2 of forestland changed to nonforest, whereas 9,120 km2 of nonforest became forestland, a net loss of 7,620 km2 of forestland during the period or −0.13%/year. The region as a whole functioned as a C sink of 627 Tg (1 teragram = 1012 g) or 70 Tg of C/year. Regional C sequestration calculated using forest type identification at the state level was 5% higher than that from the county-level identification. Integrated annual effects of LUC and harvest on reducing C stocks at the state level varied substantially, ranging from 0.4% in North Dakota to 5.1% in Delaware with an average of 3.2% across the region (3.4% in the 13 northeastern states and 2.6% in the 11 northcentral states), compared with what it would be without these effects. We also found that within the region the annual LUC rate was significantly correlated with population density at the state level (P < 0.001).
Comparative medical importance of spider bites in Spain over 1997–2020: a retrospective study based on hospital cases coded using ICD
Authors: Cortés-Fossati Fernando , Méndez Marcos
Published: April 2024

Envenomation by terrestrial toxic animals is considered a serious risk to human health worldwide. Snakes, hymenopterans, spiders, and scorpions have mainly attracted the attention of medical literature. However, the relative importance of spiders has been studied only in a few countries. Here, we present the first retrospective study on the incidence of spider bites requiring hospital care in Spain, compared to bites or stings from snakes, hymenopterans, and scorpions. Using ICD9MC and ICD10 databases from the World Health Organization’s International Classification of Diseases for the period 1997–2020, we quantified the cases of envenomation by spiders, compared to those by other terrestrial toxic animals, the demographic data of envenomation cases, the relative severity of spider bites, and the geographic distribution of envenomation cases. Overall, the incidence of acute intoxication by terrestrial toxic animals in Spain was ca. 1.23 cases per million inhabitants. In decreasing order of importance, cases were due to snakes, hymenopterans, spiders, scorpions, and myriapods. Fatal cases were extremely rare, caused mainly by hymenopterans. No fatalities were caused by spiders, scorpions, and myriapods. A greater incidence of snake bites occurred in northern Spain, but no geographical trends were found for spider bites or scorpion stings. Severe poisoning or life-threatening cases due to bites or stings from toxic terrestrial animals in Spain seems to be very low, especially for spiders, compared to other countries in the world. In general, spiders do not present a risk to human health and should not be considered a major driver of morbidity.
Forest Buffer Strips: Mapping the Water Quality Benefits
Authors: Endreny T.A.
Published: April 2024

Forest buffer strips are widely recommended for trapping nonpoint-source pollutants and protecting surface water quality, yet few models are designed to identify key areas for buffer installation and management. This article presents a conceptual model of polluted runoff dynamics to provide traction in estimating watershed-wide forest buffer needs. Inputs required for these estimates include elevation and land-cover maps, along with derived products that represent basic nutrient runoff principles.
Focus on…Professional Forestry Publishing: Looking Back on 100 Years, and Forward to 2002
Authors: Staebler R.
Published: April 2024

We've arrived at an important juncture—the 100th year of professional forestry publishing.
Commentary: Keeping Forests in Forest
Authors: Smith D.W.
Published: April 2024

We must make sure that when conservation easements are designed and implemented they work—both today and in the future.
Pingree Forest Partnership: Monitoring Easements at the Landscape Level
Authors: Sader S.A. , Ross K. , Reed F.C.
Published: April 2024

The Pingree Conservation Easement in Maine is a model of how large landowners can accomplish forest management and long-term conservation goals while realizing a financial return for this decision. The land conservation trust holding an easement has the perpetual responsibility to ensure that the owners of the property adhere to the easement terms. In this capacity, the New England Forestry Foundation has the responsibility to develop an independent, cost-effective, and scientifically defensible monitoring protocol for the Pingree easement. Elements of the monitoring program, including a three-level hierarchical monitoring method, from satellites to ground, are under development.
Conserving the Northern Forest: A Report Card on State and Federal Implementation of Recommendations of the Northern Forest Lands Council
Authors: Malmsheimer R.W. , Bentley W.R. , Floyd D.W.
Published: April 2024

In 1994, the Northern Forest Lands Council published 37 recommendations designed to maintain traditional patterns of land ownership in the Northern Forest. During the past six years, Maine, New Hampshire, New York, and Vermont each substantially or partially implemented more than 75 percent of the recommendations. State implementation was remarkably consistent and included most of the recommendations for protecting exceptional resources. The federal government implemented half of the council's recommendations, almost all of which were related to strengthening rural economies, suggesting a low national concern with most of the underlying issues.
Focus on ... Forestry Publishing: How to Prepare a Manuscript for SAF Peer Review
Authors:   none
Published: April 2024

This article delineates the roles of each SAF publication and dispels some of the mysteries of the publication process.
Conservation Easements: Permanent Shields against Sprawl
Authors:   none
Published: April 2024

Conservation easements are an effective tool for maintaining working forests, preserving environmental values, and protecting communities from excessive development pressure. The Society of American Foresters (SAF) supports conservation easements as one tool for ensuring sustainable forest management. Selling or donating conservation easements may allow landowners who are committed to sustainable management to resist pressure to sell their property to developers. Similarly, in the face of pressure to withdraw working forests from active management, conservation easements offer a way to provide adequate environmental and open-space benefits while allowing continued timber harvesting.
Commentary: Policies: Science-Based or Science-Informed?
Authors: Friedman S.T.
Published: April 2024

Because all policy issues cross disciplines, the only truly “scientific” claim for the policy product is that of the decision sciences.
Hybrid Poplar in the Pacific Northwest: The Effects of Market-Driven Management
Authors: Stanton B. , Eaton J. , Johnson J. , Rice D. , Schuette B. , Moser B.
Published: April 2024

Hybrid poplar is a new addition to the Northwest's agricultural economy, with over 50,000 acres currently in production. Originally conceived as feedstock for the energy industry, poplar has been grown primarily as raw material for the paper business. However with falling prices for wood chips, efforts are now under way to manage poplar for the solid wood market. Poplar's utility also extends to its use in the treatment of municipal and industrial wastewater, nutrient removal from agricultural runoff, and phytoremediation of industrial landfills. Future applications are likely to exploit its carbon sequestration ability in the developing markets for tradable pollution credits.
Logging Restrictions in China: A Turning Point for Forest Sustainability
Authors: Zhao G. , Shao G.
Published: April 2024

During the past 50 years, China has experienced excessive exploitation of natural forests and countrywide development of forest plantations. Although forest coverage increased from 5.2 percent in 1950 to 16.5 percent in 1998, the natural forest has sharply declined in quantity and quality. China's logging restriction, the core of the Natural Forest Conservation Program (NFCP), protects millions of hectares of forests from further clearing. This 13-year-old program helps China adjust the age structure of national forests and provides a new chance for restoring forest sustainability.