bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimum Juvenile Density, Harvesting, and Stand Structure in Even-Aged Scots Pine Stands
Authors: Hyytiäinen Kari , Tahvonen Olli , Valsta Lauri
Published: April 2024

The economics of timber production is studied using empirical data for various juvenile densities and a distance-independent individual-tree growth model specified for Finnish Scots pine (Pinus sylvestris [L.]) stands. Our results imply that explicit inclusion of quality effects on prices increases optimum juvenile density. In addition, quality effects make economic surplus of forestry more sensitive to variations in juvenile density. Optimum thinnings remove trees that have no prospects for high relative value growth. Optimum thinnings are selective thinnings that remove inferior-quality trees, some of the smallest trees and, contrary to conventions, those of the largest trees that fulfill the sawlog dimensions. Thinnings removing trees strictly above and/or below certain tree diameters homogenize the remaining growing stock by narrowing the diameter distribution. Homogeneous stand structure is economically favorable at final clearcutting because the stand can be clearcut promptly after the majority of trees have reached sawlog dimensions and have experienced the last high peak in value growth. FOR. SCI. 51(2):120–133.
Mixed Conifer Forest Duff Consumption during Prescribed Fires: Tree Crown Impacts
Authors: Hille Marco G. , Stephens Scott L.
Published: April 2024

Fire suppression has produced large forest floor fuel loads in many coniferous forests in western North America. This study describes spatial patterns of duff consumption in a mixed-conifer forest in the north-central Sierra Nevada, California. Overstory crown coverage was correlated to spatial patterns of duff depth after prescribed fire. On one site that was burned under dry conditions, almost all duff was consumed, with some remaining in overstory gaps. On a second site that was burned under moist conditions a few days after the first annual precipitation, strong spatial patterns of duff consumption were recorded with increasing distance from the base of the nearest overstory tree, the probability of duff remaining after prescribed fire increased significantly. There is strong evidence that spatial variation of precipitation throughfall resulted in higher duff moisture in gaps, whereas duff beneath crown cover was drier, and therefore, totally consumed. This study demonstrates that including a spatial component in a process-based duff consumption model would improve the accuracy of fire-effect predictions. FOR. SCI. 51(5):417–424.
Analyzing the Spread of Beech Canker
Authors: Augustin Nicole H. , Kublin Edgar , Metzler Berthold , Meierjohann Elsa , von Wühlisch Georg
Published: April 2024

We investigate the spread of Nectria canker of beech, which is a fungal chronic disease caused by Nectria ditissima Tul. et C. Tul. Data are available from a beech provenance trial. A possible influential factor on the proportion of infected trees per plot is the wind dispersal zone(s) (wdz), a categorical variable describing the distance and wind direction from diseased shelterwood, the source of infection. We investigate the effect of wdz and whether the disease incidence in the regeneration can be explained alone by the wdz using different approaches accounting for spatial correlation in the data. One method uses generalized estimating equations (GEE) where, through specification of a general variance–covariance matrix allowing for nonindependence, spatial correlation can be accounted for in the model. The second method uses generalized additive models (GAM) and the spatial autocorrelation is dealt with by modeling it as a spatial trend. The third method uses generalized linear mixed models (GLMM) with a random effect accounting for spatial correlation and heterogeneity. We show that, in the beech data, some spatial correlation is present that is over and above that accounted for by the wdz. Therefore, methods not accounting for this correlation are inappropriate. The GLMM is the most appropriate model because it manages to model the biological process best: It explains the variation in disease incidence by the wdz and by secondary infection. Hence it yields the most precise estimates. FOR. SCI. 51(5):438–448.
Interest in Cross-Boundary Cooperation: Identification of Distinct Types of Private Forest Owners
Authors: Finely Andrew O. , Kittredge David B. , Stevens Thomas H. , Schweik Charles M. , Dennis Donald C.
Published: April 2024

This article presents quantitative results from a study that evaluated private forest (PF) owner interest in cross-boundary cooperation. The intent was to reveal subgroups, referred to here as segments, of PF owners that align with different forms and levels of cooperative activities. Segmentation analysis used 783 mail-back surveys from Franklin County, Massachusetts, PF owners in spring 2002. The analysis indicates that there are four segments of PF owners in Franklin County, each maintaining a distinct level of interest in proposed forms of cooperation. Two segments define positive interest in cooperation (General Cooperators, 27%; Conservation Cooperators, 21%), and the other two represent apathy (Neutralists, 27%), and disinterest (Non-Cooperators, 24%). Furthermore, each segment presents a unique profile of items and scales that measure personal values and attitudes about cross-boundary cooperation and socioeconomic and demographic characteristics. Segment profiles show a strong association between interest in cooperation and profiling variables such as age, affluence, personal values, and attitudes. By identifying the specific needs and wants among PF owners, these findings can help in the development of responsive initiatives to promote cross-boundary cooperation in Franklin County. Furthermore, the outlined segmentation analysis could aid PF owner studies identify and describe key segments and determine interest in cross-boundary cooperation.
Modeling Individual-Tree Growth from Data with Highly Irregular Measurement Intervals
Authors: Nord-Larsen Thomas
Published: April 2024

Fitting annual tree growth and survival models to data with irregular measurement intervals requires special consideration to the interpolation of the independent variables. This study presents an iterative method for continuously updating individual-tree and stand attributes, using the hypothesized functional form of a system of forward difference equations. Based on data from permanent sample plots, parameter estimates were obtained for three first-order difference equations of diameter and height growth and mortality for European beech in Denmark. One parameter of the individual-tree diameter and height growth models was estimated locally and expresses apparent site quality. The plot-specific parameters of the individual-tree growth models were highly correlated with site index and plot-specific estimates of rate constants from a dominant height growth model. Parameter estimates of individual-tree models based on either of those indicators of site quality allow for a flexible use of the models. The study failed to establish any relation between plot-specific rate constants and soil texture variables. The resulting system of individual-tree models is consistent with tree growth and mortality expected for beech in Denmark.
Market Orientation, Strategy, and Performance in the Primary Forest Industry
Authors: Hansen Eric , Dibrell Clay , Down Jon
Published: April 2024

Over a decade of research on market orientation has produced many insights into the market orientation–performance relationship. More recently, researchers have begun to incorporate other strategic phenomena into their market orientation work. We build on this growing knowledge base by investigating the mediating role of firm strategy on the market orientation-firm performance connection. Findings show that market orientation has a positive impact on all forms of firm strategy (i.e., customer differentiation, product differentiation, channel differentiation, and overall low cost). However, only a channel differentiation strategy in combination with a market orientation produced a positive impact on firm performance. In contrast, a low cost strategy had a positive impact on firm performance in the absence of a market orientation.
Alternatives to Incorporate Uncertainty and Risk Attitude in Multicriteria Evaluation of Forest Plans
Authors: Leskinen Pekka , Viitanen Jari , Kangas Annika , Kangas Jyrki
Published: April 2024

This article studies alternative possibilities to incorporate uncertainty and risk attitude into multicriteria forest planning calculations. The interest is in studying the uncertainties involved in forest owner’s subjective preferences, but the presented approach could be applied also more generally with measurement and modeling errors concerning forest inventory and forecasting, for example. The models applied are based on ratio scale pairwise comparisons of decision elements and their statistical regression analysis, which enables versatile possibilities to incorporate the uncertainty into decisionmaking. In traditional statistical inference, uncertainty is not used directly as a decision criterion that would be required to include risk attitude. However, the statistical approach can be used, for example, to derive pairwise winning probabilities for forest plans beating each other and rank probabilities for forest plans for attaining a given rank. Several types of indices can be derived from these probabilities enabling the incorporation of risk attitude, but a more promising approach was to reduce the decisionmaking problem to contain mean and SD of the utility distributions for each forest plan and provide them as decision support to the forest owner. The approach is based on classical mean-variance utility in portfolio theory. Also, weighted average of certain percentiles of the utility distributions or weighted average of rank probabilities have their advantages.
Simulating Fire Spread with Landscape Management Scenarios
Authors: LaCroix Jacob J. , Ryu Soung-Ryoul , Zheng Daolan , Chen Jiquan
Published: April 2024

Collectively, landscape structure, fuel loading, and weather control wildland fires. Our objective was to examine the impacts of landscape structure, weather and fire-ignition location on fire spread using FARSITE. We simulated surface fires in the Chequamegon National Forest, Wisconsin, on five landscapes: a control and four harvested landscapes created using HARVEST by varying the amount (2% and 4%) and method of harvesting (i.e., clustered and dispersed), labeled C2, C4, D2, and D4. We applied three levels of precipitation and wind speed to examine weather influences. We found that fire-ignition location had the strongest effect on fire spread, followed by rain. The high-rain scenario (twice the actual rainfall) decreased burned area by an average of 241 ha (6.1%) for simulated 15-day surface fires, whereas the low-rain scenario (half of actual rainfall) increased burned area by an average of 74 ha (1.8%). The maximum size of burned area decreased in all harvest scenarios by 90 ha (1.6%), 143 ha (2.6%), 168 ha (3.1%), and 201 ha (3.7%), respectively, for landscapes D2, C2, D4, and C4. We concluded that management at the ignition location is critical and landscape-level management may be adapted to influence landscape predisposition to fire spread.
Predicting the Plot Volume by Tree Species Using Airborne Laser Scanning and Aerial Photographs
Authors: Packalé	n Petteri , Maltamo Matti
Published: April 2024

Several studies have indicated that forest characteristics can be accurately predicted using airborne laser scanner (ALS) data, but there are very few studies in which species-specific forest characteristics have been estimated. This article compares two approaches for determining species-specific volumes at plot level by combining ALS data with aerial photographs. The first approach consists of two stages: (1) prediction of total volume using ALS data, and (2) assignment of this total volume to tree species by fuzzy classification and aerial photographs, in which three fuzzy classification methods were tested. In the second approach, volumes by tree species and the total volume are predicted simultaneously using a nonparametric k-most similar neighbor (k-MSN) method based on both ALS data and aerial photographs in one phase. The test area, located in Finland, consists of 463 sample plots. Species-specific volumes were estimated for pine, spruce, and the deciduous trees as a species group, total volume being the sum of the species-specific volumes. The k-MSN method produced considerably more accurate estimates for the species-specific volumes than any fuzzy classification method, the relative RMSEs for the volumes of pine, spruce, and deciduous trees being 45.50%, 61.98%, and 92.30%, respectively, and that for the total volume 23.86%.
Best Predictors for Postfire Mortality of Ponderosa Pine Trees in the Intermountain West
Authors: Hull Sieg Carolyn , McMillin Joel D. , Fowler James F. , Allen Kurt K. , Negron José F. , Wadleigh Linda L. , Anhold John A. , Gibson Ken E.
Published: April 2024

Numerous wildfires in recent years have highlighted managers' needs for reliable tools to predict postfire mortality of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) trees. General applicability of existing mortality models is uncertain, as researchers have used different sets of variables. We quantified tree attributes, crown and bole fire damage, ground fire severity, and insect presence from a total of 5,083 trees in four 2000 wildfires in four Intermountain states. Crown scorch (percentage) and consumption (percentage) volume collectively accounted for the majority of predictive capacity in all four individual models and in the pooled four-site model. The addition of tree diameter and presence of Ips beetles in the pooled model slightly improved predictive power. Four other statistically significant variables added little to the pooled model's predictive ability. The pooled model correctly classified 3-year postfire mortality of 89.9% of the trees and had a receiver operating characteristic (ROC) score of 0.96. In the external validation step, the model correctly classified 3-year postfire mortality of 96% of 1,361 trees in a 2001 wildfire. Our results and a number of previous studies suggest that a two-variable model using percentage crown scorch volume and crown consumed volume will have applicability beyond the Intermountain West.
Partitioning Error Components for Accuracy-Assessment of Near-Neighbor Methods of Imputation
Authors: Stage Albert R. , Crookston Nicholas L.
Published: April 2024

Imputation is applied for two quite different purposes: to supply missing data to complete a data set for subsequent modeling analyses or to estimate subpopulation totals. Error properties of the imputed values have different effects in these two contexts. We partition errors of imputation derived from similar observation units as arising from three sources: observation error, the distribution of observation units with respect to their similarity, and pure error given a particular choice of variables known for all observation units. Two new statistics based on this partitioning measure the accuracy of the imputations, facilitating comparison of imputation to alternative methods of estimation such as regression and comparison of alternative methods of imputation generally. Knowing the relative magnitude of the errors arising from these partitions can also guide efficient investment in obtaining additional data. We illustrate this partitioning using three extensive data sets from western North America. Application of this partitioning to compare near-neighbor imputation is illustrated for Mahalanobis- and two canonical correlation-based measures of similarity.
Insect-Fungal Complex Associated with Loblolly Pine Decline in Central Alabama
Authors: Eckhardt Lori G. , Weber Ann M. , Menard Roger D. , Jones John P. , Hess Nolan J.
Published: April 2024

Loblolly pine decline, characterized by an expanding area of declining and dead trees, is becoming increasingly prevalent in loblolly pine (Pinus taeda L.) forests in central Alabama. A 3-year study was conducted to determine the fungal, root, and lower stem-infesting insect, and/or soil parameters associated with this decline. Hylastes salebrosus, Hylastes tenuis, Pachylobius picivorus, and Hylobius pales were significantly more abundant in declining plots than in asymptomatic plots. Root- and lower stem-infesting insects consistently carried Leptographium terebrantis, L. procerum, and L. serpens. Sampled roots had high levels of root damage, mortality, and staining typically associated with Leptographium species. Root damage and mortality preceded aboveground symptoms of short chlorotic needles, sparse crowns, reduced radial growth, and tree mortality. A sequence of biotic and abiotic factors is proposed as the cause of loblolly pine decline complex.
Policy and Management for Headwater Streams in the Pacific Northwest: Synthesis and Reflection
Authors: Adams Paul W.
Published: April 2024

The primary policy and management concern for headwater streams in the Pacific Northwest has been their potential influence on downstream water quality and fish habitat; and on federal lands, riparian wildlife habitat also has been a significant consideration. Regulations have been the primary policy tool used by state and federal agencies in the region to promote desired management for these areas, and to comply with federal laws for water quality and species protection. Management directives initially were relatively minor for headwater areas, but in recent years increased science assessments, research, and legal issues resulted in some notable policy proposals and changes for public and private lands. These measures focus on greater retention of riparian trees and other vegetation, an approach that for fish and wildlife habitat assumes significant ecological functions and benefits will follow over extended spatial and temporal intervals. Research continues to clarify ecological features and functions of headwater areas, but policy and management remain challenging because of highly variable observations downstream and because socioeconomic concerns are inconsistently addressed. Given these limitations, our policies may continue to confound decisionmakers and discourage many forest owners and managers, while also adding to an array of unintended local and global environmental consequences.
Streamside Policies for Headwater Channels: An Example Considering Debris Flows in the Oregon Coastal Province
Authors: Burnett Kelly M. , Miller Daniel J.
Published: April 2024

Management policies are increasingly debated for headwater channels given their prevalence and ecological importance in many landscapes. Quantitative differences among headwater channels may offer an objective basis for prioritizing streamside protection. Here, we examine differences among headwater channels as potential transport corridors for debris flows. Specifically, we model differences among hill slopes and headwater channels in probabilities of initiating and being traversed by debris flows that deliver to fish-bearing channels. We develop an approach to rank these probabilities and apply the ranks in delineating alternative streamside management zones. Initiation and traversal probabilities are estimated from an empirically calibrated debris-flow model using regionally available 10-m digital elevation data. Alternatives are delineated by encompassing 25%, 50%, and 75% of debris-flow susceptible hill slopes and headwater channels. Highest initiation and traversal probabilities were contained in a relatively small percentage of the study area. Encompassing lower probabilities required disproportionately larger areas. Substituting delineated alternatives for currently prescribed headwater riparian management zones decreased the total area encompassed on federal lands but increased it on private and state lands. Our intent is not to advocate for any particular alternative but to demonstrate that knowledge about how headwater channels differ over large areas can help tailor riparian policies.
Periphyton and Macroinvertebrate Assemblage Structure in Headwaters Bordered by Mature, Thinned, and Clearcut Douglas-Fir Stands
Authors: Danehy Robert J. , Chan Samuel S. , Lester Gary T. , Langshaw Russell B. , Turner Ted R.
Published: April 2024

We examined the structure of periphyton and macroinvertebrate assemblages in 18 Oregon Coast Range perennial headwater streams bordered by mature (6), clearcut (5), and thinned (7) forest treatments. Summer base flow discharge ranged from 0.02 to1.98 l/s (mean − 0.5 l/s). Periphyton was almost entirely diatoms (72 species) and assemblage characteristics were most strongly influenced by substrate characteristics. Mature treatment sites had fewer species of diatoms and less biomass than other treatments. Diatom richness was highest at sites with higher unit area discharge. Diatom assemblages were dominated by a single species (Achnanthes lanceolata [Brébisson] Grunow), which composed more than 50% relative abundance of the assemblage at nine sites. Macroinvertebrate assemblages were rich, with 194 taxa collected across all sites and 42 taxa found at a single site. Macroinvertebrate assemblages differed across treatments with higher abundance, more Chironomidae taxa, and more biomass at the clearcut treatment sites. We observed no difference in functional feeding group percentage composition across treatments, with collector-gatherers and shredders composing at least 50% abundance at all treatments. We found little difference in either periphyton or macroinvertebrate assemblages between thinned and mature treatments.
Headwater Streams and Timber Harvest: Channel, Macroinvertebrate, and Amphibian Response and Recovery
Authors: Rhett Jackson C. , Batzer Darold P. , Cross Sarah S. , Haggerty Stephanie M. , Sturm Christopher A.
Published: April 2024

Abiotic and biotic responses of 15 first-order streams to timber harvest were monitored at four sites in Washington's Coast Ranges (six watersheds clearcut to streambanks; four clearcut with stream buffers; and four references). Surveys of geomorphology, macroinvertebrates, and amphibians were conducted in 1998 (baseline), 1999 (immediately postharvest), 2000 (macroinvertebrates only) and 2001. Logging slash immediately covered or buried clearcut channels with 0.5 to 2 meters of slash, increasing roughness and trapping fine sediments, and slash still dominated channel conditions in 2001 when fine sediment fractions remained elevated relative to reference streams. In buffered and reference streams, particle size distributions were almost unchanged. Buffer blowdown was extensive (33% to 64%); increased light stimulated streamside vegetation. In 1999, clearcut streams supported higher macroinvertebrate densities of collectors and shredders, likely due to increased detrital resources. Collector response persisted into 2001, and new responses included higher overall macroinvertebrate biomass in buffered streams. No macroinvertebrate groups declined significantly in the three summers after harvest. Clearcutting to stream channels appeared to have short-term negative effects on local giant salamander and tailed frog populations but not torrent salamanders.
Biodiversity Conservation in Commercial Boreal Forestry: The Optimal Rotation Age and Retention Tree Volume
Authors: Koskela Erkki , Ollikainen Markku , Pukkala Timo
Published: April 2024

This article examines biodiversity conservation in commercial boreal forests. The means of promoting biodiversity are green tree retention and prolonged rotation age, which create dead and decaying wood artificially and via natural mortality, respectively. We extend the Hartman model to cover biodiversity benefits and to allow for leaving retention trees standing at the final felling. We first characterize qualitatively the socially optimal choice of the harvest volume and rotation age. We then assess empirically the optimal solution in a simulation model calibrated to the Finnish forestry for a pine stand. We find that biodiversity conservation increases the socially optimal rotation age beyond the Faustmann rotation age. The optimal volume of retention trees increases (decreases) with biodiversity valuation (timber price). The optimal retention volume is higher than suggested by the current forest management recommendations or certification systems.
Genotype and Population Performances and their Interactions for Growth of Coastal Douglas-Fir in Western Washington
Authors: Dean Christine A.
Published: April 2024

The Washington Wide Adaptability study (WWA) is a series of genetic tests established in 1985 across Cascade, Longview, and Twin Harbors regions of western Washington, measured for diameter over-bark at 13 years (dbh13). WWA involves parents of coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) originally selected from wild populations in Cascade, Longview, Twin Harbors, and Vail. Female parents from each population were crossed using pollen-mixes from the same (“intra”) or different (“inter”) populations. Analyses of variance: Female parent (nested within population) accounted for around 2% of total variation in dbh13. Population of the female or male parents accounted for less than 1% variation. The most important genotype × environment (GE) component was female parent (within population) × genetic test (within region), accounting for around 2% variation. Other GE effects accounted for little or no variation. The female source × pollen source (genotype × genotype, GG) effect accounted for only 0.1% of variation in dbh13. Practical implications: GG and GE interactions for dbh13 do not appear sufficiently systematic or large enough to be of practical importance in breeding coastal Douglas-fir across these regions of western Washington, at least for growth to 13 years. It appears possible to select coastal Douglas-fir genotypes that produce strong, stable growth across this range of environments. Movement of improved seed across Cascade, Longview, and Twin Harbors can lead to positive outcomes for plantation productivity at 13 years. There appears little practical benefit in having separate breeding lines of coastal Douglas-fir for these regions. Indeed, strategies of developing local purebred genotypes tested and deployed solely in a local region would most likely deliver suboptimal genetic gain.
A Maximum Size-Density Relationship between Lorey's Mean Height and Trees per Hectare
Authors: Lynch Thomas B. , Wittwer Robert F. , Stevenson Douglas J. , Huebschmann Michael M.
Published: April 2024

A linear relationship between the logarithm of Lorey's mean height and the logarithm of number of trees per hectare at maximum density can be derived from well known maximum size-density relationships associated with Reineke's stand density index and the power self-thinning principle. This leads to a system of three mathematically interrelated maximum size-density equations relating the three classically most important measures of tree size to density at its maximum. Given any two of these three equations, the third can be derived. Data obtained from unthinned control plots in a shortleaf pine (Pinus echinata Mill.) thinning study from Oklahoma are used to demonstrate these relationships. Slope estimates for the Reineke and Lorey maximum size-density lines are fitted simultaneously using three-stage least-squares with parameter constraints. First-difference models were used in the estimation procedure to reduce autocorrelation among remeasured plot data.
Common Law Liability for Landowners When Using Prescribed Fires on Private Forest Land in the Southern United States
Authors: Sun Changyou
Published: April 2024

The potential liability associated with escaped fires has been a widespread concern to forest landowners when using prescribed fires on private forestland. In this study, common law for prescribed fires on forestland in the 13 southern states was analyzed by examining published legal cases. A thorough search on the legal database of Westlaw generated a list of 27 cases at the state appellate courts. Major characteristics of these cases were summarized by features such as state, year, ownership type, and liability of landowner. Furthermore, these cases were analyzed under three focus areas: negligence rules, strict liability, and vicarious liability. Overall, the standard of care associated with the reasonable prudent person has been required for the intentional use of fire on forestland with a lawful purpose. In the past, gross negligence rule and strict liability have not been applied in the South. Vicarious liability may become a chief concern for forest landowners in the future.
Emergy Synthesis of Intensive Eucalyptus Cultivation in São Paolo, Brazil
Authors: Romanelli T.L. , Cohen M.J. , Milan M. , Brown M.T.
Published: April 2024

We used environmental accounting to evaluate high-intensity clonal eucalyptus production in São Paolo, Brazil, converting inputs (environmental, material, and labor) to emergy units so ecological efficiency could be compared on a common basis. Input data were compiled under three pH management scenarios (lime, ash, and sludge). The dominant emergy input is environmental work (transpired water, 58% of total emergy), followed by diesel (15%); most purchased emergy is invested during harvest (41.8% of 7-year production totals). Where recycled materials are used for pH amendment (ash or sludge instead of lime), we observe marked improvements in ecological efficiency; lime (raw) yielded the highest unit emergy value (UEV = emergy per unit energy in the product = 9.6E + 03 sej J−1), whereas using sludge and ash (recycled) reduced the UEV to 8.9E + 03 and 8.8E + 03 sej J−1, respectively. The emergy yield ratio was similarly affected, suggesting better ecological return on energy invested. Sensitivity of resource use to other operational modifications (e.g., decreased diesel, labor, or agrochemicals) was small (<3% change). Emergy synthesis permits comparison of sustainability among forest production systems globally. This eucalyptus scheme shows the highest ecological efficiency of analyzed pulp production operations (UEV range = 1.1 to 3.6E + 04 sej J−1) despite high operational intensity.
Precision of Total Volume Estimates Resulting from Pseudo-Bayes Estimator for Stock Tables
Authors: Green Edwin J. , Clutter Michael
Published: April 2024

In an earlier article we presented a novel estimator for stand tables. The estimator performed much better than the usual estimator in simulation studies. In this article we extend the method to volume estimation, and demonstrate via simulation studies that total volume estimates from the pseudo-Bayes stand table estimator are superior to estimates derived from the usual stand table estimator. We also derive estimates for the variance and mean squared error of the pseudo-Bayes total volume estimator and approximate confidence intervals. The intervals based on the mean squared error have approximately correct coverage and are narrower than the usual confidence intervals.
Estimating Land Rent from the Market Value of Timberland
Authors: Mehrotra Shiv N. , Carter Douglas R. , Alavalapati Janaki
Published: April 2024

Modeling empirical investment behavior of timber stand decision makers requires the use of market-generated information. Recent forestry literature has suggested that the available information on market valuations of timberland could be used to estimate empirical timberland rents as the opportunity cost. In this article we point out the fact that the market value of timberland comprises of the value of current market rent as well as values of speculated future market rents. We argue the importance of accounting for the values of speculated future rents, which could differ widely from the value of the current market rent.
Combining Tree- and Stand-Level Models: A New Approach to Growth Prediction
Authors: Yue Chaofang , Kohnle Ulrich , Hein Sebastian
Published: April 2024

Approaches to combining information generated from different models are recognized for improving forecast quality. However, such an approach has not been developed for forest growth predictions. Therefore, a study was carried out to investigate the potential of combining models to forecast forest growth. A growth prediction system was developed for Norway spruce (Picea abies [L.] Karst.) by combining growth information generated from tree- and stand-level growth models parameterized from an identical data source. The tree-level model predicts relative tree diameter growth rates of a cumulative diameter distribution. The stand-level models predict absolute stand basal area growth. The combined prediction system consists of three basic steps: preliminary prediction, combination, and feedback modification. Preliminary predictions of stand basal area growth are generated annually from both types of growth models. The preliminary predictions are then combined on the basis of a variance and covariance method, and the combined estimator is used to update the growth models in a feedback procedure. In the tree-level growth model, the updated stand basal area is subsequently disaggregated to individual trees. On the basis of a validation data set, forecasts of stand basal area with the combined prediction system were shown to gain in efficiency from 14 to 43% compared with forecasts with the tree-level model alone and from 4 to 16% compared with projections with the stand-level model, depending on the length of the projection (5–30 years).
Regression Estimation Following the Square-Root Transformation of the Response
Authors: Gregoire Timothy G. , Lin Qi Feng , Boudreau Johnathan , Nelson Ross
Published: April 2024

In a variety of regression situations, there is interest in predicting the value of Y2, yet it is useful to model it using a square root transformation, such that Y rather than Y2 is regressed on one or more covariates. The back-transformation bias of the square root transformation of the response variable of interest is presented in detail. An unbiased estimator is presented: . Its performance is compared against that of two biased estimators: and . The first two moments of these estimators are derived analytically and verified by means of a simulation study. Both biased estimators have lower mean square errors than the unbiased estimator. An example wherein aboveground biomass is the response variable is presented for illustration.
Statistical Power of Intervention Analyses: Simulation and Empirical Application to Treated Lumber Prices
Authors: Prestemon Jeffrey P.
Published: April 2024

Timber product markets are subject to large shocks deriving from natural disturbances and policy shifts. Statistical modeling of shocks is often done to assess their economic importance. In this article, I simulate the statistical power of univariate and bivariate methods of shock detection using time series intervention models. Simulations show that bivariate methods are several times more statistically powerful than univariate methods when underlying series are nonstationary and potentially involved in cointegrating relationships. In an empirical application to detect the long-run price impacts of the voluntary phase-out of chromated copper arsenate in pressure-treating southern pine lumber for residential applications, I find the multivariate methods to be more powerful as well. I identify highly significant long-run price increases of 11% for two of three treated southern pine dimension lumber price series evaluated using multivariate approaches. The univariate method detected a long-run increase only for the third product, and the statistical significance was weak, although comparable, in magnitude to the first two products.
Multipath Mitigation under Forest Canopies: A Choke Ring Antenna Solution
Authors: Danskin Scott , Bettinger Pete , Jordan Thomas
Published: April 2024

Evaluating the accuracy of global positioning system (GPS) receivers in applications under forest canopies has become an area of increasing interest. Reducing the error experienced by multipath present under forested conditions has also been a significant concern. We present results of assessing a choke ring antenna solution to the reduction of multipath effects under forest canopies. This system serves to increase the accuracy of positional fixes as well as provide a baseline for assessing multipath effects. We assessed these by comparing results to data collected by separate antenna configurations (yet same receiver) on varying slope positions and canopy conditions. Using a choke ring antenna, we found horizontal position accuracy of differentially corrected data to range from 0.32 to 0.88 m root mean square error reported at 95% confidence across a topographic gradient during leaf-on conditions. Under leaf-off conditions the horizontal position accuracy ranged from 0.35 to 0.69 m. Similar differentially corrected data collected using a standard beacon antenna showed that horizontal position accuracy ranged from 4.9 to 6.1 m during leaf-on conditions and from 3.3 to 5.8 m during leaf-off conditions. When sampled, the data from the two systems were collected within 1 minute of each other; thus, we assume a very similar plane and satellite arrangement. Coupled with topographic factors, a minimum multipath error effect could be determined for this receiver for given site conditions by taking the difference between the two levels of error.
Self-Organizing Map Analysis of Planted Soil Infiltration Systems for Treatment of Log Yard Runoff
Authors: Hedmark Åsa , Zhang Liang , Scholz Miklas , Aronsson Pär , Elowson Torbjörn
Published: April 2024

Infiltration through a soil system planted with four different species was assessed as a sustainable treatment method for logyard runoff at a field-scale experimental site in Sweden. Runoff was infiltrated through soil planted with Alnus glutinosa (L.) Gärtner (common alder), Salix schwerinii × viminalis (willow variety “Gudrun”), Lolium perenne (L.) (rye grass), and Phalaris arundinacea (L.) (reed canary grass). Analyses of variance and t tests showed no significant differences in treatment when the different plants were compared with each other, and there were also no significant differences between the tree and the grass species. The infiltration treatment was effective in reducing total organic carbon and total phosphorus in the runoff even when the loads on the infiltration system increased over time. The self-organizing map (SOM) model was applied to assess the relationships between different water quality variables and to predict total nitrogen (TN) and total phosphorus (TP) concentrations. A supplementary correlation analysis confirmed the key relationships among variables revealed by the SOM. The SOM model performed very well in predicting TN and TP concentrations with the help of other water quality variables, which can be measured more cost effectively.
Legacy of Insect Defoliators: Increased Wind-Related Mortality Two Decades After a Spruce Budworm Outbreak
Authors: Taylor Sarah L. , MacLean David A.
Published: April 2024

Effects of spruce budworm (Choristoneura fumiferana Clem.) outbreaks on growth and survival of balsam fir (Abies balsamea [L.] Mill.) and spruce (Picea spp.) are well documented, but few studies extend beyond 10 years after defoliation ceased. We used inventory data from 106 permanent sample plots in >50-year-old balsam fir stands in northern New Brunswick, Canada, to determine legacy effects of the 1969–1993 budworm outbreak on stand development up to 29 years after defoliation ceased. Defoliation data were from annual aerial surveys from 1945 to 1993 and plot ground sampling from 1985 to 1993. Plots were stratified into net stand volume development categories (decreasing, stable, and increasing 1985–2005 stemwood volume) and related to outbreak phases (outbreak, direct 1–10 years after defoliation ceased, and legacy >10 years), outbreak severity (1–4 [low], 5–8 [medium], and 9–12 [high] years of defoliation), and stand age (mature and overmature). Stand age was an important factor influencing outbreak severity (e.g., r2 = 0.383, P < 0.01). Trend and rate of volume development over time were related to past outbreak severity and increased rate of postoutbreak wind-related mortality, which peaked at 11 m3/ha/yr 11–15 years after defoliation ceased. Results indicate that aging postoutbreak stands are more vulnerable to wind disturbance events, effecting rapid stand decline.
An Accurate Approximation for Distance Distributions Arising in Airtanker Positioning and Related Problems
Authors: Provost Serge B. , Stanford David A. , Yu Kaiqi
Published: April 2024

A moment-based methodology is proposed for approximating the distribution of the distance between two random points belonging to sets that are composed of convex polygons. The resulting density approximants are expressed as the product of a beta density function and a polynomial adjustment. Because points and line segments are merely polygons projected to lower dimensions, the method can readily be used to determine the distribution of the distance between a fixed point or a line segment and polygons. In this way, it is possible to determine the distribution of the distance from an airtanker base to an initial attack zone, represented by either a convex polygon or line segment. Several illustrative examples as well as applications to the distance between an airtanker's base and its initial attack zone, and between a transportation corridor and a wildland-urban interface are presented.
Describing Maritime Pine Diameter Distributions with Johnson's SB Distribution Using a New All-Parameter Recovery Approach
Authors: Fonseca Teresa Fidalgo , Marques Carlos Pacheco , Parresol Bernard R.
Published: April 2024

Forest growth and yield models that describe the heterogeneity of a stand by implicitly defining size classes are valuable tools for sustainable forest management. In stand-level growth and yield models, often stand tables representing numbers of trees by diameter class are projected through the use of probability density functions (PDFs). Theoretical knowledge shows and empirical studies corroborate that the four-parameter Johnson's SB PDF provides greater generality in fitting diameter distributions than many of the commonly applied PDFs in forestry, such as the beta, gamma, and Weibull PDFs. Distinct parameter estimation methods are available for the Johnson's SB distribution. However, few studies have been conducted that estimate the Johnson's SB PDF using a parameter recovery approach. Also, for those studies that have used a parameter recovery approach, often one (i.e., the location) or two (i.e., the location and the range) of the four parameters are assumed to be known. In this article, we present a parameter recovery approach to recover all four parameters of the Johnson's SB PDF for diameter distributions from stand variables. The location, range, and shape parameters are recovered from the median and the first three noncentral moments of the diameter distribution. The first two of these noncentral moments correspond to the average and quadratic mean diameter. The third moment is interpreted as the product of the mean diameter for the diameter distribution based on basal area, rather than stems per ha, and the squared quadratic mean diameter. The proposed methodology is demonstrated for maritime pine (Pinus pinaster Ait.) stands in Portugal.
Testing for Change in Structural Elements of Forest Inventories
Authors: Vokoun Melinda , Wear David , Abt Robert
Published: April 2024

In this article we develop a methodology to test for changes in the underlying relationships between measures of forest productivity (structural elements) and site characteristics, herein referred to as structural changes, using standard forest inventories. Changes in measures of forest growing stock volume and number of trees for both hardwood and softwood on forestland in North Carolina are evaluated using plot-level data aggregated at both the state and survey unit level from the last three available completed Forest Inventory and Analysis surveys using exploratory data analysis and nonparametric statistics. When the survey data are aggregated at the state level, we accept the null hypothesis of no discernible between-survey differences in the means of the forest productivity measures for at least 90% of the plots in each of the four models. We also accept the null hypothesis of no discernible between-survey differences in the variance or higher moments of these forest productivity measures for at least 82% of comparisons. At a finer scale, our results show that structural stability is questionable in the Coastal Plain units of North Carolina. Overall, results provide evidence of some structural change in the forests of North Carolina but do not address the causes of such changes. The systematic comparison of forest inventories conducted in this article constitutes a new approach to testing for structural changes in forest relationships, one that can be implemented as a monitoring protocol within standard repeated forest inventories.
Note on the Variance of Radial Sampling Strategies with Random Versus Purposively Located Pivot Points
Authors: Lynch Tomas B.
Published: April 2024

Several radial sampling strategies have recently been proposed, including sector sampling, radial line sampling for estimation of area of coverage, and radial line sampling for planar area estimation. These strategies are based on either sector or line samples that emanate from a common interior point (pivot point) within the land area to be sampled. It has usually been assumed that the pivot point will be purposively located so that its location will not be random. However, random location of the pivot point within the sampling area is conceptually possible, so that it is of interest to compare the variance of estimators with purposively located pivot points with those with randomly located pivot points. When this is done, it can be determined that the variance of the estimator with a randomly located pivot point is the expected value of the conditional (on pivot point location) variance of the estimator with respect to the distribution of possible pivot point locations. Thus, for instance, if each point in the area to be sampled is equally likely to be chosen, then the variance under a random pivot point location is the mean or expected value of the conditional variance with respect to every possible pivot point location within the sample area.
Short-Term Effects of Fuel Reduction Treatments on Herpetofauna from the Southeastern United States
Authors: Kilpatrick Eran S. , Waldrop Thomas A. , Lanham Joseph D. , Greenberg Cathryn H. , Contreras Tom H.
Published: April 2024

Path analysis of fuel reduction treatments on herpetofauna across four southeastern sites of the National Fire and Fire Surrogate Study provided quantitative evidence relating changes in vegetation and fuels to herpetofauna response. Fuel reduction treatments included prescribed burning (B), a mechanical treatment (M), mechanical treatment followed by prescribed burning (MB), and an untreated control (C). Treatment effects on herpetofauna response variables were predicted by the direct and indirect effects of stand basal area, coarse woody debris volume, native herb cover, and forest floor depth. Path models were solved for lizard, snake, and reptile response to fuel reduction treatments. Lizard and reptile abundance were higher in B and MB plots than in C and M plots. Increasing native herb cover best predicted lizard and reptile abundance within B and MB plots. Native herb cover, lizard, and reptile abundance were highest in B and MB plots, and each of these response variables responded positively to B and MB.