bluuebunny/crossref_metadata_2025 huggingface dataset:
Acquisition of a Forest Estate: A Stochastic Optimization Approach for Financing and Management
Authors: Rutegård Gunnar , Lönnstedt Lars , Kallio Markku
Published: April 2024

This article addresses the financing and managing problem of a private investor who considers purchasing a forest estate. The focus is on financing the investment, timing of harvesting, and financial and nonfinancial benefits over years succeeding an acquisition. We take into account uncertainty concerning future timber prices, real rate of interest, and rate of inflation. To aid in the solution of the problem, we propose a multistage stochastic optimization model. The total amount of loan available is assumed given, while alternative interest and repayment schedules are considered for loans. The model accounts for the initial state of the forest, growth, and allowable cutting. The objective function is the expected utility. In an illustrative example, the utility for a risk averse investor is based on income for consumption. Variations of this model demonstrate the use of decision aids. These concern valuation of a forest estate, initial age distribution of forest stands, timber price volatility, initial equity, time-varying preferences for consumption, and nonfinancial benefits.
The Effects of Exchange Rate Volatility on U.S. Forest Commodities Exports
Authors: Sun Changyou , Zhang Daowei
Published: April 2024

This article addresses the impact of exchange rate volatility on U.S. exports of four forest commodities. Exchange rate volatility is measured by the standard deviation of the growth rate of real effective exchange rate of the U.S. dollar. The nonstationarity of individual time series is explicitly taken into account by employing multivariate cointegration analysis and error correction models. The results show that exchange rate volatility has a negative impact on U.S. exports in the long term, but short-term dynamics vary for different commodities. A stable currency policy in the long run helps promote U.S. exports of forest commodities, although some commodities may benefit from exchange rate volatility in the short term.
Sense of Place and Forest Science: Toward a Program of Quantitative Research
Authors: Stedman Richard C.
Published: April 2024

Sense of place is rich in theory, but quantitative research approaches often fail to reflect this richness. This schism between theory and application not only impedes the development of theory, but also the ultimate utility of the concept for integration into resource management planning. Here, several fundamental points in sense of place theory that can readily be translated into testable hypotheses are identified, as are suggestions for how they may be reformulated into hypothesis language. Sense of place is composed of descriptive and evaluative components that are a function of landscape attributes, experience with the landscape. In turn, any of these elements may affect place-related behaviors.
Diversity in Ponderosa Pine Forest Structure Following Ecological Restoration Treatments
Authors: Waltz Amy E.M. , Fulé Peter Z. , Covington W. Wallace , Moore Margaret M.
Published: April 2024

We tested the effectiveness of ponderosa pine forest restoration by comparing forest restoration treatments to untreated forest and to reconstructed forest structure in 1870 (date of Euro-American settlement) using an experimental block design at the Grand Canyon-Parashant National Monument in northwestern Arizona. Forest tree density averaged more than 20 times the historical tree density, and basal area was 4 to 6 times higher in contemporary forests than in historical forests. Restoration treatments consisted of thinning young trees to emulate the forest density, tree composition, and spatial distribution in 1870, followed by prescribed burning. Following restoration treatment, tree density was significantly reduced but remained 6 times higher than historical forests. Basal area in restored forests was still 2.5 times greater than reconstructed basal area values. Ponderosa pine dominance changed little from pretreatment data across the four blocks, averaging 60% of stems and 87% of the basal area prior to treatment and 56% of stems and 85% of the basal area following treatment. Ninety-eight percent of contemporary forest trees were less than 100 yr old prior to restoration treatment; this proportion was reduced to 82% following treatment. Restoration treatment also significantly reduced canopy cover and increased total tree regeneration. However, treatment effects on forest fuels were highly variable. Litter and duff fuel layers were significantly reduced by prescribed fire but woody debris increased. Overall forest structural diversity following treatment implies that fire behavior, wildlife habitats, and other ecological attributes will vary relatively widely in the future landscape.
Sapling Diversity in Canopy Gaps in an Ecuadorian Rain Forest
Authors: Eysenrode D.Salvador-van , Bogaert J. , Zak-Mnacek V. , Ceulemans R.
Published: April 2024

In a “terra firme” rain forest (Amazonian Ecuador) we quantified the species abundance distribution, gap size, gap isolation, sapling diversity, and gap community similarity for 24 initial gap communities. The pooled community distributions showed a log-series distribution, mainly because 2-D space was partitioned during the forest cycle's first stages, and randomness is accepted as influencing both species arrival and gap formation. Gap size interacted with species richness and evenness due to the low species abundances. The species composition in each gap was an almost unique set: on average, a gap shared <20% of its species with any other gap. A cluster analysis confirmed this observation: the first fusion occurred at a similarity level of 0.42, which related to <27% of common species. Despite this high intergap dissimilarity, association analysis showed that 33.7% of all pairwise gap comparisons represented a significant association, indicating that more species were in common than expected with random assumptions. A principal components analysis revealed three dimensions in the data; sapling diversity, community similarity, and gap size were found to be independent of gap isolation. The uniqueness of the communities in terms of sapling composition highlights the value of gaps for conservation.
Population Growth, Urban Expansion, and Private Forestry in Western Oregon
Authors: Kline Jeffrey D. , Azuma David L. , Alig Ralph J.
Published: April 2024

Private forestlands in the United States face increasing pressures from growing populations, resulting in greater numbers of people living in closer proximity to forests. What often is called the “wildland/urban interface” is characterized by expansion of residential and other developed land uses onto forested landscapes in a manner that threatens forestlands as productive socioeconomic and ecological resources. Prevailing hypotheses suggest that such forestlands can become less productive, because forest owners reduce investments in forest management. We develop empirical models describing forest stocking, thinning, harvest, and tree planting in western Oregon, as functions of stand and site characteristics, ownership, and building densities. We use the models to examine the potential impacts of population growth and urban expansion, as described by increasing building densities, on the likelihood that forest owners maintain forest stocking, precommercial thin, harvest, and plant trees following harvest. Empirical results support the general conclusion that population growth and urban expansion are correlated with reduced forest management and investment on private forestlands in western Oregon (USA). Results have potential implications for both economic outputs and ecological conditions, as well as for wildfire risks at the wildland/urban interface. FOR. SCI. 50(1):33–43.
An Assessment of the Impacts of Forest Management on Aboriginal Hunters: Evidence from Stated and Revealed Preference Data
Authors: Adamowicz Wiktor , Boxall Peter , Haener Michel , Zhang Yaoqi , Dosman Donna , Marois Juanita
Published: April 2024

Assessing the impacts of forest harvesting activities on Aboriginal people and incorporating these considerations into forest management plans is one of the challenges facing Canadian forest managers. In this study, we model hunting behavior using stated and revealed preference data on subsistence use of wildlife resources. We use this framework to assess the impacts of forest management changes on Aboriginal people in northwestern Saskatchewan. Innovative approaches to data collection are employed to address challenges in obtaining data in these contexts. The econometric analysis combines the stated and revealed preference information to account for limitations in the revealed preference data. Monetary measures of welfare are examined, but we also assess resource compensation and zoning as mechanisms for addressing the impact of forest harvesting on subsistence wildlife use. The results also demonstrate the use of geographic information system information in linking forest management and Aboriginal resource use. FOR. SCI. 50(2):139–152.
Comparison of Annual Inventory Designs Using Forest Inventory and Analysis Data
Authors: Arner Stanford L. , Westfall James A. , Scott Charles T.
Published: April 2024

Three annual inventory designs, a periodic design, and a periodic measurement with midcycle update design are compared using a population created from 14,754 remeasured Forest Inventory and Analysis plots. Two of the annual designs and the midcycle update design allow updating of plots not measured using sampling with partial replacement procedures. Comparisons are based on root mean square error and estimator bias determined for net volume (m3/hectare) and mean annual net volume change. For the annual designs, both individual year and moving average estimates are investigated. The latter are compared to both the population means of the most recent year used in the average and to population means covering the same period as the estimate. Among annual designs, a rotating panel design, in which an equal portion of the total sample is measured each year without remeasurement until the start of the next measurement cycle, produced the smallest root mean square error for estimates of mean net volume. For multiple-year comparisons, the rotating panel and periodic designs resulted in the smallest root mean square errors; for single-year comparisons, the periodic design resulted in the smallest root mean square error. For mean annual volume change, the smallest root mean square error was produced by the periodic design. Among annual designs, the rotating panel design resulted in the smallest root mean square error for multiple-year comparisons of volume change, while a design allowing annual updates of estimates using generalized least squares resulted in the smallest root mean square error for single-year comparisons. FOR. SCI. 50(2):188–203.
Improving Taper Equations of Loblolly Pine with Crown Dimensions in a Mixed-Effects Modeling Framework
Authors: Leites Laura P. , Robinson Andrew P.
Published: April 2024

A mixed-effects modeling framework was applied to Max and Burkhart's (1976) (MB) taper equation for loblolly pine (Pinus taeda L.). The advantages of such a strategy over ordinary least squares were: (1) more accurate specification of the correlation structure of the data and (2) the ability to assess the potentially explainable variation at the tree level. Significant relationships were established between tree-level crown dimensions and parameter estimates. The study data comprised 197 plantation-grown loblolly pine trees of 10 different ages in Uruguay. Four versions of MB were evaluated: (1) the original equation, (2) the original equation fitted with mixed effects, and two adapted versions: (3) the first included crown variables and fixed effects, (4) the second included crown variables and mixed effects. The crown variables were tree-level crown length and crown length ratio. The best of the four competing equations included both of the crown variables as well as tree-level random effects, suggesting that some linear tree-level variability may yet be explained by variables not considered in this study. Testing on an independent validation data set did not show over-fitting problems. For prediction purposes, the equations with added crown variables were more precise but not less biased. FOR. SCI. 50(2):204–212.
Importance of Foliar Nitrogen Concentration to Predict Forest Productivity in the Mid-Atlantic Region
Authors: Pan Yude , Hom John , Jenkins Jennifer , Birdsey Richard
Published: April 2024

To assess what difference it might make to include spatially defined estimates of foliar nitrogen in the regional application of a forest ecosystem model (PnET-II), we composed model predictions of wood production from extensive ground-based forest inventory analysis data across the Mid-Atlantic region. Spatial variation in foliar N concentration was assigned based on a correlation with mean July temperature for deciduous forests and with latitude for coniferous forests. Although the slight variation observed in foliar N in conifers had little effect on predicted wood production, large differences in N concentration in deciduous trees increased agreement with field surveys by 12–59% in individual states and by 17% across the region. The validation revealed the need to develop regional foliar N concentration equations that represent the spatial variations of N concentration in deciduous forests to improve PnET-II's predictions. FOR. SCI. 50(3):279–289.
Old-Growth Forest Canopy Structure and Its Relationship to Throughfall Interception
Authors: Nadkarni Nalini M. , Sumera Mark M.
Published: April 2024

Structural elements of the forest canopy such as foliage, branches, and epiphytes intercept, retain, and regulate inputs of matter and energy to the forest floor in spatially variable ways. Most studies of forest structure-function have analyzed relationships between canopy structure and the spatial distribution of inputs at the forest stand level. Few studies have focused on within-canopy spatial scales or identified the functional roles of particular structural components. Our objective was to quantitatively assess the amount of canopy structural material to a critical functional attribute: canopy interception of rainfall. We investigated forest canopy structure with a novel technique, “vertical canopy cylinder transects,” that uses access from a construction crane in an old-growth coniferous forest in Washington State. We characterized the diversity and composition of forest structural elements (tree foliage and branches by species, epiphytes by functional group) and found the majority of the foliage and epiphytes concentrated in the upper- to mid-canopy, with some vertical stratification of the epiphyte functional groups. We also quantified one aspect of forest function, the volume and variability of throughfall interception. We documented a strong relationship between the amount of structural elements and rainfall interception (R2 = 0.79). This approach of quantifying three-dimensional canopy structure at particular locations had higher predictive ability for throughfall volume than previous approaches that were not able to gain direct access to canopy components. FOR. SCI. 50(3):290–298.
Development of Canopy Structure in Pseudotsuga menziesii Forests in the Southern Washington Cascades
Authors: Van Pelt Robert , Nadkarni Nalini M.
Published: April 2024

We quantified stand-level structural diversity in eight stands of temperate coniferous forests that ranged in age from 50 to 950 years in the southern Washington Cascade Range. Stands were chosen based on the dominance, or former dominance in the case of the oldest stands, of Pseudotsuga menziesii. In addition, to avoid confusing patterns of structural development, only stands that had a single disturbance of origin were used. Within each stand, randomly located transects were laid out that were proportional in size to the dominant tree height. Tree heights and diameters ranged up to 90 m and 309 cm, respectively. A total of 5,737 trees among the 32 transects were mapped and measured for height, diameter, crown height, and four crown radii. The structure of the canopy in the younger stands is a simple, fairly even monolayer. This contrasts with the older stands, which have a very complex, highly diffuse canopy with extreme variability in both horizontal and vertical dimensions. The stands with the highest structural complexity were between 500 and 650 years old and retained from 17 to 76 Pseudotsuga stems/ha. Our oldest site had only one living Pseudotsuga/ha. Mean diameter of just the Pseudotsuga trees was less than 55 cm for stands less than 200 years and over 180 cm for the most complex old-growth stands. One measure of stand structural diversity, the standard deviation of dbh, ranged from less than 25 (stands less than 200 years) to values greater than 50 (most complex old-growth sites). A similar relationship exists when using the standard deviation of height. Large snags and logs important for wildlife were present only in the old-growth stands and were abundant in the most structurally diverse stands. FOR. SCI. 50(3):326–341.
Structural Phenology of the Leaf Community in the Canopy of a Liriodendron tulipifera L. Forest in Maryland, USA
Authors: Parker Geoffrey G. , Tibbs Donna J.
Published: April 2024

We measured the vertical dynamics of leaf area in a tall, tulip poplar (Liriodendron tulipifera)-dominated, deciduous forest on the Maryland coastal plain over three growing seasons (one intensively) using nondestructive, ground-based observations. Leaf area index (LAI) and leaf area density (LAD) were calculated by vertical level, time, and species; the time-integrated duration of leaf display (leaf area extent, LAE) was estimated by species and vertical level. In this stand LAI rises rapidly in the spring, declines slightly during the growing season, and then rapidly in the fall. In the intensively studied year, total LAI peaked at 7.1 m2m-2 LAE was 1259 m2m-2day, and the length of the canopy season (time from half-maximum LAI at leaf-out to the half-maximum at decline) was 191 days. The maximum growing season LAI, the date of leaf emergence, and the LAE differed among years, ranging 0.61 m2m-2, 14 days, and 261 m2m-2day, respectively. However, the timing of leaf fall was more consistent, ranging only 6 days. Each species differs in its height distribution, density, and timing of foliar display. In the canopy, leaf number, area, and duration are the bases of species importance; these differ substantially by species from typical importance values derived from stem-based attributes (density, basal area, biomass). FOR. SCI. 50(3):387-397.
A Walkthrough Solution to the Boundary Overlap Problem
Authors: Ducey Mark J. , Gove Jeffrey H. , Valentine Harry T.
Published: April 2024

Existing methods for eliminating bias due to boundary overlap suffer some disadvantages in practical use, including the need to work outside the tract, restrictions on the kinds of boundaries to which they are applicable, and the possibility of significantly increased variance as a price for unbiasedness. We propose a new walkthrough method for reducing boundary overlap bias that diminishes or eliminates the need to work outside the tract and accommodates irregular boundaries easily. Under typical conditions, the walkthrough method eliminates the boundary overlap bias associated with most objects near the border and reduces it for the remaining objects. The walkthrough method is object-centered in conception and implementation, but the measurements required are simple. The walkthrough method complements existing methods for correcting boundary overlap bias and should prove especially helpful when conditions make existing methods difficult or impossible to use. FOR. SCI. 50(4):427–435.
Forest Parameters Estimation in a European Mediterranean Landscape Using Remotely Sensed Data
Authors: Mallinis George , Koutsias Nikos , Makras Apostolos , Karteris Michael
Published: April 2024

Satellite remote sensing provides new possibilities and challenges to forest managers for monitoring and managing forest ecosystems. The value/use of high-resolution satellite data of Landsat Thematic Mapper (TM) to estimate tree density, basal area, basal volume, and forest biomass was investigated under an operational perspective in a spatially heterogeneous Mediterranean landscape in northern Greece. Digital classification using Fisher's linear discriminant functions produced an overall accuracy of 82%. A series of multispectral transformations were also performed, and the derivative synthetic channels were used along with the original ones as explanatory variables in the model developed. The forest stand parameters that were investigated in the study presented a similar but weak correlation with the Landsat-5 TM spectral channels. Among them, TM4 and TM7 presented the highest correlation with forest stand parameters, while the integration of the derivative synthetic channels increased the correlation coefficients and resulted in statistically significant predictive models. FOR. SCI. 50(4):450–460.
Area-Independent Sampling for Total Basal Area
Authors: Flewelling James W. , Iles Kim
Published: April 2024

An unbiased direct estimator of total basal area for a stand is presented; stand area need not be known. Sampling can use horizontal point samples or fixed-area plots distributed on a regular grid or randomly selected. The sample space extends beyond the stand boundary. The estimator for basal area makes no distinction between plots whose centers are interior to the stand boundary and plots whose centers are outside. Only trees within the stand boundary are tallied. For horizontal point sampling, the estimator is the product of the sample tree count, the basal area factor, and the area per grid point, with the latter being derived from grid spacing. This method avoids the complexities associated with most other estimators designed to minimize or eliminate edge bias. The proposed method may require more sample points to achieve the same level of precision as competing estimators. FOR. SCI. 50(4):512–517.
Fusion of Small-Footprint Lidar and Multispectral Data to Estimate Plot- Level Volume and Biomass in Deciduous and Pine Forests in Virginia, USA
Authors: Popescu Sorin C. , Wynne Randolph H. , Scrivani John A.
Published: April 2024

The principal study objective was to explore the feasibility of using small-footprint lidar data and multispectral imagery to estimate forest volume and biomass on small (0.017-ha) plots. In addition, the spatial dependency of residuals between ground-measured and lidar-estimated variables was investigated. The lidar data set was acquired over deciduous and pine stands in the southeastern United States. Individual trees were identified on the lidar-derived canopy height model by local maximum focal filtering with both square and circular windows of variable size. The size of the dynamically varying window was based on the height of the canopy and the taxonomic group as derived from coregistered multispectral optical data. Lidar-measured parameters at an individual tree level (height, crown diameter) were used with regression models and cross validation to estimate plot-level field inventory data, including volume, biomass, basal area, and diameter at breast height (dbh). Maximum R2 values for estimating biomass were 0.32 for deciduous trees (RMSE 44 Mg/ha) and 0.82 for pines (RMSE 29 Mg/ha). When estimating volume, maximum R2 values for deciduous trees were 0.39 (RMSE 52.84 m3/ha) and 0.83 for pines (RMSE 47.9 m3/ha). Calculation of Moran's I coefficient for each regression model revealed a lack of significant autocorellation of the residuals at 0.05 level. Both model fit and prediction for volume and biomass models for deciduous and pine plots indicated that the circular window shape is more appropriate to locate individual trees with lidar. Using the fused data set, lidar and optical imagery, as opposed to using lidar data alone, always improved biomass and volume estimates for pines and in some cases for deciduous plots as well. FOR. SCI. 50(4):551–565.
Modeling the Likelihood of Crown Fire Occurrence in Conifer Forest Stands
Authors: Cruz Miguel G. , Alexander Martin E. , Wakimoto Ronald H.
Published: April 2024

The unknowns in wildland fire phenomenology lead to a simplified empirical model approach for predicting the onset of crown fires in live coniferous forests on level terrain. Model parameterization is based on a data set (n = 71) generated from conducting outdoor experimentalfires covering a significant portion of the spectrum of burning conditions associated with the initiation of crown fires. A logistic model is developed to predict the likelihood of crown fire occurrence based on three fire environment variables, namely the 10-m open wind speed, fuel stratagap (equivalent to live crown base height in some stands), estimated moisture content of fine dead fuels, and one fire-behavior descriptor–surface fuel consumption. The model correctly predicts 85% of the cases in the data set used in its development, and the receiver operatingcharacteristic statistic is 0.94. The model is evaluated for its sensitivity to its inputs, and its behavior is compared with other models used in decision support systems to operationally predict crown fire initiation. The results of a limited test of the model against two independent experimentalfire data sets for distinctly different fuel complexes is encouraging. FOR. SCI. 50(5):640–658.
Aesthetic Impacts of Disturbances on Selected Boreal Forested Shorelines
Authors: Hunt Len M. , Haider Wolfgang
Published: April 2024

This article investigates the aesthetic impacts of anthropogenic and fire disturbances on forested shorelines for most coniferous forest types of the boreal forest. The novel use of the psychophysical landscape-perception approach to near-vista-view shoreline settings makes this application unique. Evaluations of aesthetic quality by laypeople show that severe fire and clearcut-logging disturbances make the forested shorelines much less attractive when compared to undisturbed sites. The analysis also provides a detailed examination of the relationships between undisturbed and logged sites by investigating the relationship between reserve width (i.e., the amount of land that separates the shoreline from logging activities) and aesthetic quality. A regression model of aesthetic evaluations demonstrates that aesthetics is positively related to undisturbed sites, to reserve width, and to the slope of the land. An interaction term of the reserve width and slope of the land is negative, which suggests that the reserve width necessary to mitigate the effects of logging on flat lands is smaller than the reserve width needed to mitigate logging on steeper lands. The model can also be used for predictive purposes such as estimating a reserve width that may be necessary to mitigate all visual effects of logging on shoreline sites. FOR. SCI. 50(5):729–738.
Book Reviews: Conserving Forest Biodiversity: A Comprehensive Multiscaled Approach
Authors: Groninger John W.
Published: April 2024

Landscape-level management, driven by conservation objectives, will undoubtedly continue to play a role in natural resource decisionmaking for the foreseeable future. A fundamental justification for landscape management is that reliance on designated protected areas and reserves alone is inadequate for the maintenance of forest biological diversity. According to the authors, management practices on unreserved, commodity-producing lands (referred to throughout this book as “the matrix”) will determine the success or failure of efforts to maintain forest biological conservation and forest health. This book makes the case for management at several scales to achieve these objectives within large, contiguous forest systems.
Sap Beetle Species (Coleoptera: Nitidulidae) Visiting Fresh Wounds on Healthy Oaks During Spring in Minnesota
Authors: Juzwik Jennifer , Skalbeck Thomas C. , Neuman Marc F.
Published: April 2024

Many species of sap beetles have been implicated as vectors of the oak wilt pathogen, (Ceratocystis fagacearum), but the species responsible for most aboveground transmission of the fungus is unknown. The abundance of adult sap beetle species inhabiting <7-day-old, artificially made wounds on healthy oaks during Apr.–June of 2 years in Minnesota, and the frequencies with which viable propagules of the fungi were present on each, were determined. Sap beetles were most abundant on wounds created in May, and 1–3-day-old wounds yielded higher numbers of insects than 4–6-day-old wounds. Of the beetles collected, >95% were Colopterus truncatus and Carpophilus sayi. C. fagacearum was isolated from 75% of 594 adults assayed for the fungus. The average number of viable propagules for pooled data of individuals of each species ranged from <100 to 18,000. Frequencies of fungus isolation differed by days after wounding, study location, and sap beetle species. These results, when coupled with previous findings on predominant species associated with oak wilt fungi mats, support the hypothesis that Co. truncatus and Ca. sayi are the principal sap beetle species transmitting C. fagacearum from diseased to healthy oaks in Minnesota. FOR. SCI. 50(6):757–764.
Associations between Forest Fire and Mexican Spotted Owls
Authors: Jenness Jeffrey S. , Beier Paul , Ganey Joseph L.
Published: April 2024

In 1993, the US Fish and Wildlife Service listed the Mexican spotted owl (Strix occidentalis lucida) as threatened, in part because of the rising threat to its habitat from stand-replacing wildfires. In 1997, we surveyed 33 owl sites that, in the previous four years, had burned at various levels ranging from light controlled burns to stand-replacing fires. We compared owl occupancy and reproduction in these burned sites to 31 unburned owl sites with similar habitat and topography. Although unburned sites showed higher proportions of both occupancy and reproduction, the negative relationship observed between recent fire occurrence and owl occupancy rank was statistically weak (Test for Marginal Homogeneity, P = 0.110). Owls tended not to be present where pure pine stands (Pinus spp.) comprised a large proportion (38–85%) of burned sites, but no other factors relating to habitat or fire severity had a significant, biologically interpretable influence on occupancy rank. We suspect that relatively low-intensity ground fires, including most prescribed fires, probably have little or no short-term impact on Mexican spotted owl presence or reproduction, but we have no data on long-term effects of fire. We recommend proactive fuels-management treatments in areas not currently occupied by owls as a means of reducing fire risk in areas occupied by owls. Within areas occupied by owls, judicious treatments may be appropriate after case-by-case evaluations of potential benefits and risks within those sites. FOR. SCI. 50(6):765–772.
A Pòlya-Urn Resampling Scheme for Estimating Precision and Confidence Intervals Under One-Stage Cluster Sampling: Application to Map Classification Accuracy and Cover-Type Frequencies
Authors: Magnussen Steen , Stehman Stephen V. , Corona Piermaria , Wulder Michael A.
Published: April 2024

A Pòlya-urn resampling scheme (PURS) is introduced as an alternative to classical inference (CLAS) for applications related to map accuracy and estimating cover-type frequencies from land-cover maps. PURS is akin to a Bayesian bootstrap procedure for generating a predictive posterior distribution of sample estimates. PURS is a simple alternative to the complexity of deriving Taylor-series approximation (TSA) to CLAS variance estimators and reliance on asymptotic normality for construction of confidence intervals. The potential advantages of the resampling scheme are explored in simulated sampling of actual data from three 102–107-km2 large study sites. PURS root mean square errors (rmse) of six measures of classification accuracy were slightly lower than TSA to CLAS rmse. PURS estimated standard errors and coverage rates of confidence intervals (95%) for bias-corrected classified cover-type frequencies were, in most cases, superior to corresponding TSA. Yet variance estimators and confidence intervals constructed for a cover type occupying less than 5% of a study site were consistently underestimated by both methods. PURS is adaptable to a wide range of forest resource survey designs. FOR. SCI. 50(6):810–822.
Predicting the Spatial Distribution of Leaf Litterfall in a Mixed Deciduous Forest
Authors: Staelens Jeroen , Nachtergale Lieven , Luyssaert Sebastiaan
Published: April 2024

An accurate prediction of the spatial distribution of litterfall can improve insight in the interaction between the canopy layer and forest floor characteristics, which is a key feature in forest nutrient cycling. Attempts to model the spatial variability of litterfall have been made across forest types, but the reported models have not yet been compared. We predicted the spatial distribution of leaf litterfall for the same mixed hardwood stand using inverse distance interpolation, ordinary kriging, single and multiple regressions based on plot basal area, and three individual-tree models. Models were calibrated using litterfall data (n = 67) of white birch (Betula pendula Roth), pedunculate oak (Quercus robur L.), and northern red oak (Quercus rubra L.). Model performance was compared using an independent validation data set (n = 37). Interpolation techniques did not reliably estimate spatial patterns of leaf litterfall (r < 0.60, n = 37). However, models incorporating tree data, such as linear regressions and individual-tree models, successfully reproduced the observed spatial litterfall heterogeneity of each species (r > 0.80). No model was able to predict the variability of the total leaf litterfall of the three species. We conclude that, for an intimately mixed forest stand, a model that simulates leaf dispersal of individual trees is likely to be the best choice for predicting the spatial distribution of leaf litterfall. FOR. SCI. 50(6):836–847.
Nonparametric Tests for Profit Maximization with Incomplete Data: Application to the Pulp and Fine Paper Production in Finland
Authors: Kallio A. Maarit I. , Hänninen Riitta
Published: April 2024

Forest sector models give relevant information to decision makers only if they are based on correct economic hypotheses. This requires that the data from which the model parameters are estimated are consistent with the a priori assumptions made on market agents' behavior and competition patterns. For static models, rather simple nonparametric tests exist for checking such consistency. Such tests also provide an analyst with insights on possible errors in the data and the suitability of the data for the particular econometric model that the analyst has in mind. This article proposes data tests for the competitive or noncompetitive profit-maximization hypothesis that can also be used with incomplete data. The tests are applied to quarterly data on the production of pulp and fine paper in Finland. It is found that the data may not represent profit-maximizing price takers. Although this can be due to, e.g., integrated production, missing dynamics, or noncompetitive behavior—a hypothesis that was indeed found to be consistent with the fine paper data—it is evident that the modeler should not use these data in estimating a parametric industry model that builds on price-taking profit-maximizing behavior. The results emphasize the importance of testing the data before modeling. FOR. SCI. 51(1):19–28.
Management of Mixed-Species, Uneven-Aged Forests in the French Jura: From Stochastic Growth and Price Models to Decision Tables
Authors: Rollin François , Buongiorno Joseph , Zhou Mo , Peyron Jean-Luc
Published: April 2024

A deterministic matrix growth model of uneven-aged stands of fir, spruce, and hardwood trees was extended to recognize random shocks. The results showed that the expected basal area of hardwoods, mainly beech, was substantially higher in the long run than that predicted by the deterministic model. A parallel stochastic model of prices was also developed from past data. It showed that real prices had no trend but that they were autocorrelated over time. The stochastic stand and price models were simulated simultaneously to obtain the probabilities of transition between stand and market states. This transition probability matrix was used in Markov decision-process models to calculate the best decision in each possible stand and market state. The policies examined included maximizing net present value, or expected tree diversity, production, or annual returns, subject to constraints on net present value, expected tree diversity, and basal area. A general mathematical programming method is presented to optimize economic or ecological objective functions subject to multiple constraints with or without time discounting. In the French Jura context, the solutions suggested that high net present value could be obtained while maintaining the average basal area near its current level, and keeping a high level of tree diversity. Accounting for risk called for more intense harvesting to raise revenues, and it led to stands that were much more diverse than suggested by deterministic solutions. FOR. SCI. 51(1):64–75.
Tree Density Estimations Using a Distance Method in Mali Savanna
Authors: Picard Nicolas , Kouyaté Amadou M. , Dessard Hélène
Published: April 2024

The biological characteristics of trees in tropical dry savannas make it difficult to conduct inventories of tree density, and this has aroused interest in distance-based methods. This study proposes a distance-based tree density estimator using Matérn point processes, generating clustered spatial patterns. It was defined as the maximum likelihood estimator of the density, based on an approximate distribution of the distance from a random point to the pth nearest tree. It was compared with seven estimators identified in the literature as the most efficient. The estimators were compared on a benchmark of 10 point processes, with six being adjusted to observed tree patterns in six Mali savannas (West Africa). The proposed estimator was generally the most efficient. However, this result ignores that (i) all estimators do not require the same effort on the field, (ii) the point-processes benchmark was restricted to Matérn processes, and (iii) all estimators are not equivalent with respect to measurement errors. FOR. SCI. 51(1):7–18.
Developmental Pathways following the Harvest of Oak-Dominated Stands
Authors: Gould Peter J. , Steiner Kim C. , Finley James C. , McDill Marc E.
Published: April 2024

The postharvest development of 90 formerly oak-dominated stands in Pennsylvania was examined to identify developmental pathways that led to a range of stand compositions and structures in the third decade after harvest. Operational data collected through the course of timber sale administration were used to quantify preharvest overstory composition and the distribution and composition of advance regeneration and regeneration 2 years after harvest. Stands were re-measured during their third decade of development. Based on their third-decade compositions, stands were grouped into four distinct classes. The development of each class was then traced by comparing preharvest overstory, advance regeneration, and postharvest regeneration compositions between classes. Stands in the OAK class maintained dominance by oaks throughout stand development, resulting in an average of 83.8% oak stocking in the third decade after harvest. Stands in the MIXED and RED MAPLE classes began with lower levels of advance oak regeneration and lost oak dominance relative to preharvest stand compositions. The MIXED class experienced recruitment of pioneer species after harvest, resulting in stands where black birch (Betula lenta L.) and other species are important components, despite being poorly represented as advance regeneration. The RED MAPLE class had abundant red maple (Acer rubrum L.) advance regeneration and lacked postharvest recruitment of oaks or pioneer species, leading to the development of red maple-dominated stands. Stands in the UNSTOCKED class suffered preharvest mortality and regeneration (primarily red maple) declined after harvest, resulting in regeneration failures. The four developmental pathways demonstrate the importance of specific stand conditions at the time of harvest and, to a lesser extent, just after harvest to future stand development. FOR. SCI. 51(1):76–90.
Trees, Crops and Soil Fertility: Concepts and Research Methods
Authors: Nichols J. Doland
Published: April 2024

Up until about 20 years ago, agroforestry literature was generally vague and descriptive–“trees are good and farmers and graziers should plant more of them.” Existing systems, especially ones developed in the tropics, were described, but usually not systematically studied, and an overall optimism about the benefits of trees on farms prevailed. Many years were spent in international research and development projects promoting “agroforestry,” particularly the use of nitrogen-fixing, multiple-use (products and services) trees, especially Leucaena leucocephala. Often farmers have not taken up the recommended systems. Although they may not have phrased it in academic language, their basic objections were something like, “aggressive fast-growing trees will take up space and compete with crops or pasture for water, nutrients, or light; and the benefit-to-cost ratio, at least in the short term, is not favorable.”
Comparison of Nearest Neighbor Methods for Estimating Basal Area and Stems per Hectare Using Aerial Auxiliary Variables
Authors: LeMay Valerie , Temesgen Hailemariam
Published: April 2024

Simulations were used to compare variable-space nearest neighbor methods for imputing stems per ha and basal area per ha (ground measured) for complex stands (many species and sizes) of southeastern British Columbia, Canada. Species composition and other characteristics obtained for every stand by interpreting aerial photography were used as auxiliary variables. The simulations included three distance metrics (squared Euclidean distance, most similar neighbor, and absolute distance), three intensities of stands with full information (20%, 50%, and 80%), two sets of aerial variables (mixed versus moderately high correlations with ground variables), and three averaging methods (nearest neighbor, average of three nearest neighbors, and distance weighted average of three nearest neighbors weighted). Increasing the number of stands with full information to 50% from 20% resulted in increased accuracy, with no noticeable improvement with a further increase to 80%. Of the three distance metrics, the most similar neighbor measure gave good results in imputing stems per ha and basal area per ha, particularly when there was a mixture of correlations, high and moderate, between the auxiliary (aerial) variables, and the ground variables. No large gain was noted in using the average of three neighbors rather than a single neighbor. FOR. SCI. 51(2):109–119.
Is There a Single National Lumber Market in the United States?
Authors: Yin Runsheng , Baek Jungho
Published: April 2024

This article revisits the question of whether the law of one price (LOP) holds for the United States lumber markets, with the most disaggregate data and a large number of price combinations for different products, regions, and species. We also paid close attention to issues related to how we should conduct unit root tests with a potential structural break, whether we should include intercept and time trend in a co-integration model, and what lag length should be chosen. After exhaustive investigations, we find overwhelming evidence supporting the LOP for the entire United States softwood lumber market. We believe that this finding has profound implications on our market modeling and policy analysis. FOR. SCI. 51(2):155–164.
Effects of Vegetation Patches on Soil Nutrient Pools and Fluxes within a Mixed-Conifer Forest
Authors: Erickson Heather E. , Soto Patricia , Johnson Dale W. , Roath Brent , Hunsaker Carolyn
Published: April 2024

At a spatially heterogeneous mixed-conifer forest in the central California Sierras, we quantified total carbon (C) and nitrogen (N), inorganic N, and net N mineralization in organic (O) and surface (0–15 cm) mineral soils, and in situ fluxes of inorganic N and ortho-phosphate using resin lysimeters under three patch types: closed canopy conifer, sparsely vegetated open canopy, and Ceanothuscordulatus thickets. In O horizons, total N and C pools ranked: closed canopy > Ceanothus > open canopy. In mineral soils, total N pools under Ceanothus exceeded those under closed canopy patches by about 30%. For 2 years, nitrate concentrations and rates of net N mineralization in O horizons were 4× greater under Ceanothus than under the other patch types. Similarly, ammonium concentrations and net N mineralization in mineral horizons were more than 80 and 200% greater, respectively, under Ceanothus than under the other patch types. In situ fluxes of nitrate were 4× greater beneath Ceanothus for 1 year, and no differences were found among the patch types for another year. Despite the interannual variability, our data suggest that Ceanothus contributes to a greater proportion of total N mineralized than based on cover alone, and may be important for forest nutrition under current conditions and after forest burning. FOR. SCI. 51(3):211–220.
Biophysical Controls on Soil Respiration in the Dominant Patch Types of an Old-Growth, Mixed-Conifer Forest
Authors: Ma Siyan , Chen Jiquan , Butnor John R. , North Malcolm , Euskirchen Eugénie S. , Oakley Brian
Published: April 2024

Little is known about biophysical controls on soil respiration in California's Sierra Nevada old-growth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly among the patch types, ranging from 2.0 to 4.5 µmol m−2 s−1 and from 0.9 to 2.9 µmol m−2 s−1 during the 1999 and 2000 measuring periods, respectively, with the maximum in CECO and the minimum in OC. Multiple peaks of seasonal SRR were functions of soil temperature and moisture dynamics. The relationship between SRR and soil temperature switched from a positive to a negative correlation when soil moisture dropped from saturation to drought. Time lag, as a function of soil moisture, was included in an exponential model to assess the effects of soil moisture on SRR in this seasonal water-stressed ecosystem. The total soil C flux summed by an area-weighted average across all three patch types was 660 ± 163 g C m−2 from May to Oct. 2000. These results may be applicable to other water-stressed forests in the Mediterranean climate zone, and have implications for the conservation of soil carbon. FOR. SCI. 51(3):221–232.