bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tree Mortality in Mixed Pine–Hardwood Stands Defoliated by the European Gypsy Moth (Lymantria dispar L.)
Authors: Eisenbies Mark H. , Davidson Christopher , Johnson James , Amateis Ralph , Gottschalk Kurt 
Published: April 2024

Abstract
Defoliation by the European gypsy moth (Lymantria dispar L.) and subsequent tree mortality have been well documented in the northeastern United States. In this study we evaluate tree mortality after initial defoliation in mixed pine–hardwood stands in the southeastern United States as the range of European gypsy moth expands. In 1993, 46 mature pine–oak and pine–sweetgum stands were selected on the coastal plain in Maryland and Virginia along the advancing gypsy moth front. Initial stand conditions, defoliation, and tree mortality after a single defoliation outbreak were monitored for 4 years. Susceptible oaks and sweetgum were defoliated at the greatest intensities. After defoliation, mortality in attacked stands was 4.4 m2/ha higher in pine–oak stands and 1.7 m2/ha higher in pine–sweetgum stands, representing 13 and 3% of the total basal area, respectively. Mortality of pines was observed mainly among suppressed and intermediate trees. Logistic regressions were derived to correlate individual tree mortality to stand and tree factors associated with gypsy moth attack. On the basis of these models, susceptible understory species with degraded crowns in pine–oak stands were at the greatest risk of mortality. Dominant overstory pines in pine–hardwood stands appear to be at low risk.
Using Inventory Projections to Evaluate Management Options for the Nontimber Forest Product of Epiphytic Moss
Authors: Peck JeriLynn , Hoganson Howard , Muir Patricia , Ek Alan , Frelich Lee 
Published: April 2024

Abstract
Several US national forests have implemented moratoria on harvesting moss in the absence of management plans that can demonstrate long-term sustainability. To fill this gap, harvest schedules are presented for epiphytic moss in northwestern Oregon based on a variation of the classic volume control model. Commercial moss inventory over a 150-year simulation period was estimated as initial inventory plus biomass increment minus mortality and legal harvest. A 50-year exclusion period between harvests was chosen based on the minimum time estimated to replenish moss and to maintain acceptable species richness for the moss and the invertebrate taxa that inhabit it. Mean estimates for the input parameters were used for a “baseline” scenario and the upper and lower 95th percentile confidence intervals for the estimates were used for “optimistic” and “conservative” scenarios describing moss growth and yield estimates. Recent moss harvest permit levels exceed those that would sustain resource yield and biodiversity even under the optimistic scenario. Avoiding resource depletion would require reducing permit levels by 3.5- and 1.4-fold under baseline and optimistic scenarios, respectively. Sustained yield would require reductions of 6.8- and 1.7-fold, respectively.
Stochastic Simulation of Forest Regeneration Establishment Using a Multilevel Multivariate Model
Authors: Miina Jari , Heinonen Jaakko 
Published: April 2024

Abstract
Here we present a method for simulating high unexplained variation in establishment of tree seedlings in planted Norway spruce (Picea abies [L.] Karst.) stands. The simulation method is based on an existing hierarchical multilevel multivariate model for establishment of regeneration (Miina, J., and T. Saksa. 2006. New For. 32:265–283). The model includes seven simultaneously estimated models for numbers and heights of tree seedlings on 20-m2 plots within a regeneration area. The variation in plot-level expectations is described by fixed effects and two nested multivariate normal random effects. Conditionally, given the expected values, one of the count variables is underdispersed and four are overdispersed relative to Poisson law. The conditional distributions of the square roots of the height variables are normal. For the conditional joint distribution, the model defines the product-moment cross-correlation matrix, which includes both positive and negative cross-correlations. The first two moments do not, however, uniquely define the marginal distributions of the count variables or the joint distribution of all seven variables. We applied binomial distribution for the underdispersed Poisson variation and negative binomial distribution for the overdispersed Poisson variation. The conditional joint distribution was defined by a multivariate normal copula and the marginal distributions. Despite relatively low cross-correlations among responses, if the cross-correlations among random components of the responses were ignored in stochastic simulations, the amount and costs of precommercial thinning (i.e., cleaning out competing broadleaves) were greatly underestimated. If all random effect components in model parameters were dropped, the error increased markedly.
Seed Germination: Mathematical Representation and Parameters Extraction
Authors: El-Kassaby Yousry A. , Moss Ian , Kolotelo Dave , Stoehr Michael 
Published: April 2024

Abstract
A method for mathematically describing cumulative seed germination using the four-parameter Hill function is described. The function's four parameters allowed both direct or indirect biological interpretation of germination behavior and the impact of seed pretreatments on germination improvement. Three parameters, a, b, and c, allowed direct assessment of germination capacity (%), the shape and steepness of the germination course, and germination speed (time to reach 50% germination). The fourth parameter y0 permitted estimation of the lag time (germination onset). The mathematical expression of cumulative seed germination of unstratified and stratified seed made it possible to quantitatively estimate seedlot dormancy and the amount of germination improvement caused by a specific seed pretreatment. This was accomplished by estimating the area between the two cumulative germination curves through integration. The utility of the proposed approach was demonstrated using germination data from wind-pollinated, individual genotypes (half-sib families) of lodgepole pine (Pinus contorta var. latifolia) and bulk seedlots of lodgepole pine and white spruce (Picea glauca).
How (Un)Certain Is the Future in Forestry? A Comparative Assessment of Uncertainty in the Forest and Agricultural Sector
Authors: Hoogstra Marjanke A. , Schanz Heiner 
Published: April 2024

Abstract
Several authors have stated that, because of the long time horizons underlying forestry processes, the forest sector encounters far more uncertainty than is experienced by any other industrial or agricultural production processes, especially regarding the long future. To gain more insight into the extent to which foresters experience uncertainty in their work field, a content analysis has been carried out to reveal how foresters from the United States and (Germanic) Central Europe (Germany, Austria, and Switzerland) experience uncertainty. The outcomes were compared with the experiences of uncertainty in a more short-term oriented sector, namely the agricultural sector (also in the United States and in Central Europe). Although the findings must be interpreted carefully, the research reveals that, in contrast to what was expected, foresters experience the future as the most certain time period. Decisionmakers in forestry, as in other business sectors, seem to ignore the uncertainty and pretend that the future is certain. This strategy implies considerable risk and, therefore, for forest management to be effective, there is no other way than actively confronting the futurity dilemma.
A Gamma-Poisson Distribution of Point to k Nearest Event Distance
Authors: Magnussen Steen , Picard Nicholas , Kleinn Christoph 
Published: April 2024

Abstract
Distance sampling of events in natural or seminatural populations often indicates a larger variance in the distance to the kth nearest event than expected for events distributed completely at random. Overdispersion contributes to the well-known bias problem of distance sampling density estimators. Distance distribution models that accommodate overdispersion in the data should lead to more robust estimators of density. To this end we propose a gamma-Poisson distribution model for distances from a point to k nearest events. The model assumes a gamma distribution of local densities of randomly distributed events. Properties of the distribution and estimation of the parameters and event density are detailed for both constrained and unconstrained sampling. Four examples, one with simulated data from a known negative binomial distribution and three with simulated distance sampling in natural and seminatural stem-mapped tree stands, illustrate the promising performance of this new distribution, both as a model for distances and for density estimation. The modeling approach extends to other mixing distributions.
Simulating Light Availability under Different Hybrid Poplar Clones in a Mixed Intensive Plantation System
Authors: Paquette Alain , Messier Christian , Périnet Pierre , Cogliastro Alain 
Published: April 2024

Abstract
Fast-growing hybrid poplars have been proposed as a means of achieving restoration objectives on former agricultural land by providing shelter for slower-growing species. Intensive two-stage scenarios of mixed plantations are also possible using valuable hardwoods interplanted among hybrid poplars. The latter would be harvested at maturity (approximately 20 years) once their protective role has been accomplished, leaving more space for the full development of the second cohort. We implemented simulations of hybrid poplar growth in the SORTIE-ND model and used it to test scenarios with clones varying in growth and crown allometry, different hardwood species, and spatial arrangements, to maximize production of both groups. Important differences in growth and allometry were manifested among clones over time, which translated into important differences in available light between rows. Sustained growth for most hardwoods appeared optimal using wider spacings of 16 m, compared with 12 m, between poplar rows. To our knowledge, this is the first attempt to integrate fast-growing hybrids and intensive silviculture scenarios into spatially explicit models. These models are necessary support tools for the efforts now being invested in intensive silviculture in the face of diminishing forest resources, increasing wood and fiber demands, and climate change.
Using the Space-Time Permutation Scan Statistic to Map Anomalous Diameter Distributions Drawn from Landscape-Scale Forest Inventories
Authors: Rubin Benjamin , MacFarlane David 
Published: April 2024

Abstract
Landscape-scale tree stem diameter distributions contain information that is potentially useful for evaluating the structural sustainability of forests, describing the impacts of past disturbances, and predicting future forest structure. One obstacle to interpreting diameter distributions at large scales is that typical boundaries used to define populations, such as ecoregions or counties, may not correspond to areas with different diameter distributions. We modified the space-time permutation scan statistic (STPSS), a disease outbreak detection technique, to identify and map areas in Pennsylvania, USA, where diameter distributions based on Forest Inventory and Analysis plots appeared different from the diameter distributions of the state as a whole. We used linear, exponential, and polynomial regressions to model the diameter distributions of the entire state and of areas indicated by the STPSS. The best fit regression models were linear and polynomial as determined by Akaike's information criterion and log likelihood statistics. Regression models confirmed that the STPSS identified areas where the diameter distributions of all species, oaks, and red maple differed from their corresponding statewide populations. Through a nested application of the STPSS at successively smaller spatial scales, we mapped core zones within each area where the difference was greatest.
Assessing the Relative Importance of Tangible and Intangible Resources: Empirical Results from the Forest Industry
Authors: Lähtinen Katja , Haara Arto , Leskinen Pekka , Toppinen Anne 
Published: April 2024

Abstract
The importance of a diverse resource base to competitiveness of firms has been emphasized in resource-based view (RBV) literature and empirical studies done on various industries. Despite this emphasis, resource assessment methodologies within the RBV framework have been seldom approached, and the relative importance of different resources for business operations is not well understood. The data of the study were collected among large- and medium-sized sawmills within the Finnish forest industry. The objective of this study was to assess within the RBV framework the importance of tangible and intangible resources in business operations of sawmills. This was accomplished by introducing a multicriteria decision analysis (MCDA) method suitable for practical resource assessment. According to the results, personnel, managerial, raw material, and financial resources were the most crucial for sawmills. In the future, applying the MCDA to resource assessments could be combined, e.g., with a financial statement analysis to evaluate the effects of resource usage decisions on business performance.
Canopy Cover Estimation in Semiarid Woodlands: Comparison of Field-Based and Remote Sensing Methods
Authors: Ko Dongwook , Bristow Nathan , Greenwood David , Weisberg Peter 
Published: April 2024

Abstract
Canopy cover is a widely used measurement for characterizing forest structure. Numerous comparative studies have been conducted for a variety of canopy cover field methods. However, comparisons of canopy cover methodology are lacking for semiarid woodland, characterized by short-statured trees, simple vertical canopy structure, and relatively low canopy cover. Furthermore, there is limited knowledge on the compatibility between field and remote sensing methods, despite the increasing interest in scaling up canopy cover estimates from forest stands to large landscapes. In this study we investigated the use and functional similarity of various canopy cover field methods and a remote sensing method in semiarid pinyon-juniper woodlands in the Great Basin of the western United States. We compared line intercept, vertical densitometer, spherical densiometer, and crown radius methods with each other and with a remote sensing method using object-oriented image classification of digital orthophotography. Our results show that methods using a wider angular view generated higher canopy cover estimates. This difference may be greater in semiarid woodland that in mesic forest because of differences in canopy architecture. Canopy cover from remote sensing showed a nonlinear relationship with that from field-based methods. Such nonlinearities need to be considered when remote sensing is used to extrapolate canopy cover from stand to landscape scales or when field-based canopy cover estimates are used to calibrate or validate remote sensing classifications.
Facilitating Integrated Recreation Management: Assessing Conflict Reduction Benefits in a Common Metric
Authors: Lindberg Kreg , Fredman Peter , Heldt Tobias 
Published: April 2024

Abstract
Recreation management on public land often involves trade-offs. For example, cross-country skiers may experience conflict with snowmobiles. A potential management response is trail separation, which may lead to gains to skiers but also ecological and financial costs associated with creation of a new trail. If separation involves snowmobile access restrictions, there may be experiential losses for that user group. Management responses are not always based on explicit identification and integration of the gains and losses accruing across diverse stakeholders and dimensions; economics provides a criterion, a metric, and measurement tools to facilitate such integration. A Swedish case study illustrates this approach and assesses values accruing to skiers from reduced snowmobile presence. Cross-country skiers were sampled on-site in the southern Jämtland mountain region, and follow-up mail surveys included choice experiment scenarios. Conditional logit analysis of the 1,468 completed scenarios indicates that skier welfare gains from conflict reduction are substantial and reflect both direct and indirect contact. A change from sharing trails to not seeing, hearing, or smelling snowmobiles leads to gains of 185 kronor (US$23) per skier party.
Modeling Stand Density Effects on Taper for Jack Pine and Black Spruce Plantations Using Dimensional Analysis
Authors: Sharma Mahadev , Parton John 
Published: April 2024

Abstract
A taper equation was developed for jack pine and black spruce trees growing at varying density using a dimensional analysis approach. Data used in this study came from stem analysis on 1,135 jack pine (Pinus banksiana Lamb.) and 1,189 black spruce (Picea mariana [Mill.] B.S.P.) trees sampled from 25 even-aged monospecific plantations in the Canadian boreal forest region of Northern Ontario. About half of the trees were randomly selected for model development, with the remainder used for model evaluation. A nonlinear mixed-effects approach was applied in fitting the taper equation. The predictive accuracy of the model was improved by including random-effects parameters for a new tree based on upper stem diameter measurements. Three scenarios of using upper stem diameter measurements to predict random effects were examined for predictive accuracy: one diameter at any height along the bole; two diameters, one each from below and above breast height; and three diameters, one from below and the other two from above breast height. The upper height at which the diameter was measured was limited to 65% of total tree height for practical reasons. For the first scenario, the model calibrated using a diameter measurement from between 34 and 38% of total height provided the best predictions of inside-bark diameters. For the second scenario, the model calibrated using one diameter from near the stump and the other from close to 65% of total height produced the least bias in predicting inside-bark diameters. For the third scenario, the model calibrated using the diameters from near the stump and at approximately 35 and 65% of total height provided the highest prediction accuracy.
A Multivariate Linear Mixed-Effects Model for the Generalization of Sample Tree Heights and Crown Ratios in the Finnish National Forest Inventory
Authors: Eerikäinen Kalle 
Published: April 2024

Abstract
The aim of this article was to develop a prediction model that could use the geographically representative but locally sparse sample tree data of the Finnish National Forest Inventory (FNFI) efficiently and account for the correlation structures in these data when generalizing sample tree characteristics over tally trees by species. The sample tree characteristics modeled were tree height and the ratio of live crown length to tree height. These are needed for all FNFI tally trees to obtain their stem volumes and biomasses. As a result, a multivariate linear mixed-effects model with species-specific parameters designed for the multiresponse FNFI data was developed. The fixed parts of the two linear models of the simultaneous system consist of both tree and stand-level independent variables such as dbh, mensurable stand characteristics, and site quality indicators. Because of the hierarchically correlated data, the intercepts and the slopes (i.e., the coefficients associated with tree characteristics) in the two models were assumed to vary randomly over clusters and forest stands within them. The random coefficients were also associated with components for random species effects. The selected formulation of the random parts of the models makes it possible to obtain localized species-specific curves for clusters and forest stands even with one measured sample tree. The results show that the multivariate mixed-effects model with species-specific components is a stable, efficient predictor and well applicable to locally sparse but geographically representative data of the FNFI type.
Variability in Nest Density, Occupancy, and Home Range Size of Western Bluebirds after Forest Treatments
Authors: Hurteau Sarah , Sisk Thomas , Dickson Brett , Block William 
Published: April 2024

Abstract
Complex land use and fuels management histories have resulted in significant changes in composition, structure, and function of southwestern forests and subsequent changes in the extent and quality of wildlife habitats. We evaluated how several currently used fuel reduction treatments (e.g., mechanical thinning and prescribed fire alone and in combination) affect nest attributes, nest density, nest tree occupancy, and home range size of Western Bluebirds (Sialia mexicana) in ponderosa pine (Pinus ponderosa)-dominated forests of northern Arizona. Nest attributes, such as number of eggs or nestlings, varied among treatments, but did not differ statistically. Western Bluebird nest density was significantly influenced by treatment, with densities higher in treated areas, even though snag density was lower in treated areas than in control areas. The average (± SE) area of the 50% contour, across all treatment units, was 0.42 ± 0.07 ha, and the average area of the 90% contour was 2.36 ± 0.30 ha. Home range sizes for both probability contours evaluated were 1.5 times larger in the thin-only treatments than in the control units. Conversely, home range area in thin-and-burn treatments was approximately 30% smaller than in control units. The largest home ranges occurred in the burn-only treatments. Our results suggest that forest treatments, such as thinning and prescribed fire are, in general, beneficial to Western Bluebirds, but that low snag retention may be problematic in areas receiving prescribed fire as part of their treatment action.
Thinning and Prescribed Fire Effects on Snag Abundance and Spatial Pattern in an Eastern Cascade Range Dry Forest, Washington, USA
Authors: Hessburg Paul F. , Povak Nicholas A. , Salter R. Brion 
Published: April 2024

Abstract
Mechanical thinning and prescribed burning practices are commonly used to address tree stocking, spacing, composition, and canopy and surface fuel conditions in western US mixed conifer forests. We examined the effects of these fuel treatments alone and combined on snag abundance and spatial pattern across 12 10-ha treatment units in central Washington State. A snag census was conducted before and immediately after treatments on each unit where all snags were measured and classified as either “new” (&lt;1 year as a snag) or “old” (&gt;1 year as a snag) mortality, and bark beetle species were censused on the bottom 3-m of the bole. Before treatment, snags were found in all units and more than two-thirds of the snags were ponderosa pine. Burning (burn-only and thin + burn combined) treatments led to increases in total snag abundance in all but the largest diameter class. Snag abundance in the large snag class (&gt;60 cm dbh) decreased in most treatment units indicating that units with high abundance before treatment had the potential to lose more snags with treatment or time. Treatments also affected the spatial distribution of snags. The thin-only treatment reduced clumpiness, leading to a more random snag distribution, whereas the burn-only and thin + burn treatments generally retained or enhanced a clumped snag distribution. Bark beetles attacked &gt;75% of snags across all units before and after treatments, and red turpentine beetle (Dendroctonus valens LeConte) occurrence tended to increase after prescribed burning. Managers can use this information to tune silvicultural prescriptions to meet stocking, spacing, and fuel reduction objectives while retaining or recruiting snags, thereby increasing the utility of conditions for certain wildlife species.