bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying Fuzzy Logic to Tree Bucking Control
Authors: Kivinen Veli-Pekka , Uusitalo Jori
Published: April 2024

In this article, we introduce a fuzzy logic based control system that calibrates the price list controlling the tree bucking of a modern harvester according to the unique conditions of an individual stand prior to harvesting. The system employs a bucking simulator that predicts an output distribution for any price list generated. A fuzzy controller is used to recalculate the price list according to the difference between the demand distribution and the actual output distribution. The tests with perfect knowledge of the stems showed that the control system clearly works efficiently. However, calibrating the price list prior to harvesting seemed to be very sensitive to the precision of the prior information on the trees. The simulations showed that while no gain can be achieved by preharvest inventorying of the stands and fine-tuning the price lists with this imperfect knowledge, the same or even better bucking results can be obtained by the bucking-to-demand process in which the price list is continuously adjusted after each cutting. For. Sci. 48(4):673–684.
The Epidemiology of Pitch Canker of Monterey Pine in California
Authors: Storer Andrew J. , Wood David L. , Gordon Thomas R.
Published: April 2024

The progression of pitch canker disease, caused by Fusarium circinatum, was followed over 4 yr (1992–1996) in urban stands of Monterey pine, Pinus radiata, with initially zero, light, moderate, and severe disease intensity. The disease progressed from a few to many branch tip symptoms, followed by the appearance of cankers on the main stem. Symptomatic branch tips at the start of the study were predictive of tree mortality or removal after 4 yr. Trees with canopy dieback and stem cankers were often attacked by the red turpentine beetle, Dendroctonus valens. Among initially disease-free trees, disease progression and final severity were greater in plots with initially severe and moderate disease intensity. Apparent infection rates did not differ between plots with different initial disease intensities. Over the 4 yr of the study, 2% of trees in the five plots with most severe disease never exhibited disease symptoms and thus may be resistant to pitch canker. In addition, 7% of symptomatic trees in these plots never had more than two symptomatic branch tips, which may reflect a moderate level of resistance. FOR. SCI. 48(4):694–700.
Performance Differences and Genetic Parameters for Four Coastal Provenances of Loblolly Pine in the Southeastern United States
Authors: Sierra-Lucero V. , McKeand S.E. , Huber D.A. , Rockwood D.L. , White T.L.
Published: April 2024

Provenance-progeny test plantations of loblolly pine (Pinus taeda L.) were assessed for survival, height, mean annual increment for volume (MAIV), and fusiform rust infection (caused by Cronartium quercuum [Berk] Miyabe ex Shirai f. sp. fusiforme) at 5, 10 and 15 yr. Each of the 7 sites contained from 6 to 15 open-pollinated families from each of 4 provenances: Atlantic Coastal Plain (ACP), Central Florida (CF), Marion County Florida (MCF), and Gulf Coastal Plain (GCP). The main objectives for establishing these trials were to: (1) characterize the genetic architecture among and within these provenances; and (2) determine the relative genetic worth of these provenances for possible inclusion in advanced-generation breeding programs in the Coastal Plain in the southeastern United States.

Provenance and family within provenance effects were strong and highly significant for height and MAIV, but only family effects were significant for rust infection. The Florida provenances were the best growers at all ages and at all sites. The poor growth of the Gulf Coastal Plain provenance compared to the Atlantic Coastal Plain provenance could not be explained by climatic or edaphic differences between the regions of origin. We speculate that gene flow from slower growing sources on the western side of the Mississippi River may be at least partly responsible for the poor growth of the GCP loblolly.

Because of the relatively stable performance of the provenances and the families within provenances at each site and across ages, selection of superior families for growth and rust resistance between ages 5 and 10 yr should result in substantial genetic gain in the Coastal Plain. For. Sci. 48(4):732–742.
Comparative Analysis of Stochastic Models for Financial Uncertainty in Forest Management
Authors: Yoshimoto Atsushi , Shoji Isao
Published: April 2024

We propose 13 continuous time stochastic models based on the state-dependent volatility process for stochastic log price dynamics, and then conduct a comparative analysis for their performance. Comparison is carried out on the basis of AIC (Akaike's Information Criterion), the mean squared error of the model, and the likelihood ratio test. Parameter estimation is performed by using the local linearization method. Our experiments with 13 tree species sold on the Japanese timber market show that the general form of the state-dependent stochastic model yields the highest performance in terms of AIC for most logs. In addition, we find that price dynamics with a tendency to increase over time can be captured by such a stochastic model, with the drift term as a linear function of the state. It is also shown that a functional form of the diffusion part or volatility of the model plays an important role in model performance with regard to the AIC, while a functional form of the drift part of the model does so in the mean squared error for forecasting one period ahead. FOR. SCI. 48(4):755–766.
Scale and Unit Specification Influences in Harvest Scheduling with Maximum Area Restrictions
Authors: Murray Alan T. , Weintraub Andrés
Published: April 2024

This article examines alternative approaches for representing a forest region to be scheduled for harvesting, where the primary concerns are maximizing return and imposing a maximum contiguous area of disturbance restriction. One approach assumes that any two adjacent management units exceed a regulated maximum area of disturbance. An alternative approach recognizes that management units may be substantially smaller than the maximum area restriction, so simultaneously disturbing two neighboring units does not necessarily represent a maximum area violation. The distinguishing feature of these two approaches is the way in which a forest is spatially represented. A single time period, 351 management unit harvest scheduling problem is utilized to investigate whether analysis results are subject to manipulation when forest representation, and associated modeling, is interpreted in different ways. Empirical results highlight significant economic and spatial variation in harvest schedules when maximum area restrictions are imposed using alternative approaches. For. Sci. 48(4):779–789.
Pheasants, Partridges, and Grouse: A Guide to the Pheasants, Partridges, Quails, Grouse, Guineafowl, Buttonquails, and Sandgrouse of the World
Authors: Carroll John P.
Published: April 2024

The pheasants and relatives have been the subject of a large number of extensive treatises, including works by Beebe (1918– 1922) and Delacour (1977), which are considered classic treatments of some of the species included in Pheasants, Partridges, and Grouse. Although these “gamebirds” contain a number of the best-known and studied birds in the world, most notably the domestic chicken, the ring-necked or common pheasant (Phasianus colchicus), and the wild turkey (Meleagris gallopavo), many species are not familiar even to ornithologists.
Spatial Methods for Quantifying Forest Stand Structure Development: A Comparison Between Nearest-Neighbor Indices and Variogram Analysis
Authors: Kint Vincent , van Meirvenne Marc , Nachtergale Lieven , Geudens Guy , Lust Noël
Published: April 2024

Insight into forest stand structure is of capital importance for understanding forest ecosystem structure and function. The ability of two spatial methods—based on (1) nearest-neighbor indices and (2) geostatistical variogram analysis—to quantify forest stand structure and its development over short time periods was investigated in two mixed Scots pine stands. Results show that the two methods are complementary in quantifying the three components of forest stand structure: positioning, mixture, and differentiation. The principal advantage of nearest-neighbor indices was their capacity for detecting subtle structure changes; moreover, they are easy to calculate and interpret. Variograms of height and indicator variograms of presence/absence data were more complicated in their use and required more input data, but provided additional information on the number, impact, and range of structure-determining factors such as competition and management. In this context, the concept of the mark variograms is discussed. FOR. SCI. 49(1):36–49.
Comparison of Estimators for Rolling Samples Using Forest Inventory and Analysis Data
Authors: Johnson Devin S. , Williams Michael S. , Czaplewski Raymond L.
Published: April 2024

The performance of three classes of weighted average estimators is studied for an annual inventory design similar to the Forest Inventory and Analysis program of the United States. The first class is based on an ARIMA(0,1,1) time series model. The equal weight, simple moving average is a member of this class. The second class is based on an ARIMA(0,2,2) time series model. The final class is based on a locally weighted least-squares regression prediction. The estimator properties were tested using a simulation population created from Forest Inventory and Analysis (FIA) data from northeastern Minnesota. Estimates of total volume per acre, on-growth volume per acre, mortality volume per acre, proportion of sawtimber acreage, proportion of poletimber acreage, and proportion of sapling acreage were calculated using several weighted average estimators in each year. These were compared to the simulation population, for which the true values are known, and an unbiased yearly estimator. When computing estimates, the ARIMA(0,1,1) based estimators produced the lowest root mean squared error of each of the three classes. However, in a few years the bias for some variables was high. The maximum percent increase between the estimator with the lowest root mean squared error and the simple moving average was 7.31%. Of all the estimators, the simple moving average performed well in terms of mean square error in virtually every situation. It tended to be best among the estimators tested if spatial variation was large and change was relatively small. It was not consistently best in terms of mean square error in the presence of moderate change and large spatial variation. For. Sci. 49(1):50–63.
Estimates of Additive, Dominance and Epistatic Genetic Variances from a Clonally Replicated Test of Loblolly Pine
Authors: Isik Fikret , Li Bailian , Frampton John
Published: April 2024

Nine full-sib families were generated using a factorial mating design consisting of three female and three male loblolly pine (Pinus taeda L.) parents. Full-sib seedlings and clones of the same families were planted in two test sites in Alabama and Florida. Additive, dominance, and epistatic genetic variances were estimated for growth traits and for fusiform rust incidence for ages 1 through 6. Epistatic variances did not have a significant role in growth traits, but additive gene actions were the major source of genetic variance in loblolly pine. Dominance variance for height, diameter, and volume was negligible at early ages, but it was considerable at age 6, particularly for volume. Fusiform rust incidence appeared to be partially under additive and epistatic gene actions and genetic differences among the clones within families accounted for 48.6% of the total variance. Within-plot variance for clones was always smaller than that within-plot variance for seedlings of the same full-sib families. Clonally replicated progeny tests may provide special advantages for loblolly pine tree improvement programs, as they would substantially increase the efficiency of testing by reducing the microenvironmental variance and better estimation of genetic parameters. This may provide greater genetic gains, particularly for fusiform rust incidence. Potential effects of the small parental size and violations of the assumptions of the genetic model are discussed. Negative additive and nonadditive genetic correlations between the growth traits and fusiform rust incidence are encouraging for rapid and simultaneous improvement of the traits during the same cycle selection. FOR. SCI. 49(1):77–88.
Genetic Gain and Selection Efficiency of Loblolly Pine in Three Geographic Regions
Authors: Xiang Bin , Li Bailian , McKeand Steve
Published: April 2024

Genetic parameters of annual height to 8 yr and 4 to 8 yr volume were examined for Northern, Coastal, and Piedmont populations of loblolly pine (Pinus taeda L.) from analyses of 23 disconnected half-diallel progeny tests in the southern United States. Genetic gains in year 8 volume predicted by various selection methods at age 6 revealed that selection on volume yielded more gain than selection on height. Among test regions, the Coastal population had the greatest correlated response, followed by the Piedmont population and Northern populations. Family plus within family selection was the most effective to achieve genetic gain for early selection on both height and volume. Additional gain (10–40%) can be achieved by capturing the nonadditive genetic component through mass production of fullsib crosses or vegetative propagation. Early selection efficiency was examined by using the ratio of either gain per year or present value between indirect selection and selection of year 8 volume. Optimal selection ages were determined for various selection methods. The analysis of selection efficiency showed earlier selection could be more efficient than selection on volume at age 8 or later. Family selection can be performed as early as age 3 for height and at age 4 for volume, which was the earliest measurement year for volume in this study. Family plus within family had its optimal selection age at age 3 or age 4. Based on the relatinship of age 8 with rotation gain, the selection criteria and timing were also appropriate. FOR. SCI. 49(2):196–208.
Book Reviews: Forest Hydrology: An Introduction to Water and Forests
Authors: Schultz Richard C. , Lee Kye-Han
Published: April 2024

In recent years, water resource issues concerning quality, quantity, and timing have been dominating natural resource management discussions around the world. Forest hydrology has historically been an important topic in forest management leading to some of the earliest forest research conducted in the United States. While there are a few textbooks on forest hydrology, there has always been a dilemma in what to include in such books. The hydrologic cycle may be briefly covered in ecology courses. However, without a significant introduction to water resources, most forestry and nonforestry students who enroll in a forest hydrology course do not have sufficient background in water resources to really understand the effect forests have on water quality, quantity and timing. A textbook for most forest hydrology courses should not only cover topics on forest impacts on water but also provide the basics of water properties, movement, and storage in the atmosphere, soil matrix, and surface water bodies. Putting both major topic areas in one manageable textbook requires trade-offs that do not dilute either subject area too much, but rather skillfully blend the two together. Mingteh Chang has done just that in writing this book.
Potential Improvements in the Characterization of Forest Canopy Gaps Caused by Windthrow Using Fine Spatial Resolution Multispectral Data: Comparing Hard and Soft Classification Techniques
Authors: Foody Giles M. , Jackson Robin G. , Quine Christopher P.
Published: April 2024

Gaps often form in forest canopies due to windthrow and have important management and ecological implications. Remote sensing has considerable potential for the provision of information on gap properties but this has not been fully realized. This is largely due to the use of conventional (hard, one-pixel one-class) image analysis techniques and imagery with a relatively coarse spatial resolution. This article investigates the potential to extract information on gap properties from fine spatial resolution airborne thematic mapper imagery using soft classification techniques that allow image pixels to have multiple and partial class membership. It is shown that a standard hard maximum likelihood classification may be used to derive an accurate map of the land cover of a forested site (95.1%) from which gaps in a canopy of Sitka spruce were accurately identified (94.5%). The maximum likelihood classification was also softened by outputting probabilities of class membership for each pixel. Softening the classification increased the information on gap properties that could be extracted from the data. In particular, the accuracy with which key gap properties, such as gap area, perimeter length and shape, were estimated was higher in the outputs of the softened than hard classification. Thus, while strong correlations between the remotely sensed and ground data estimates of gap area (r ≥ 0.96) and perimeter (r ≥ 0.87), based on a sample of 36 gaps, were derived from all classifications, the accuracy with which gap properties were estimated was generally highest when a soft classification was used. For example, the use of a soft rather than hard classification resulted in the root mean square error in estimating gap area declining from 144.90 to 132.87 m2. Furthermore, the soft classification allowed the sharpness of the gap boundary to be estimated, enabling further gap properties to be inferred. In particular, the soft classification output enabled the direction of the wind event causing the initial damage to be estimated, and it may aid the definition of sites with a future risk of windthrow. FOR. SCI. 49(3):444–454.
Predicting the Spatial Distribution of Aspen Growth Potential in the Upper Great Lakes Region
Authors: Gustafson Eric J. , Lietz Sue M. , Wright John L.
Published: April 2024

One way to increase aspen yields is to produce aspen on sites where aspen growth potential is highest. Aspen growth rates are typically predicted using site index, but this is impractical for landscape-level assessments. We tested the hypothesis that aspen growth can be predicted from site and climate variables and generated a model to map the spatial variability of aspen growth potential across the upper Great Lakes region. The model predicting aspen growth from climate and site characteristics performed nearly as well as the site index model. Sites currently growing aspen have a somewhat lower growth potential than do nonaspen upland sites. The mean growth potential of national forest sites is lower than on other ownerships, except in Michigan. Upland sites with the highest aspen growth potential had higher growth potential than sites currently growing aspen, suggesting that productivity could be increased by shifting the location of aspen production. Only 6.7% of the highest growth sites are located on national forests across the region. The spatially explicit nature of these results may facilitate cooperative planning to better optimize where aspen will be managed across a subregion to enhance regional productivity and to focus management where the potential for production is the greatest. FOR. SCI. 49(4):499–508.
Optimal Forest Taxation under Private and Social Amenity Valuation
Authors: Koskela Erkki , Ollikainen Markku
Published: April 2024

This article analyzes the socially optimal forest taxation in the rotation framework when the government has a binding tax revenue requirement. In the Faustmann model, the optimal design of taxation consists of nondistortionary taxes, such as site productivity tax, site value tax, or profit tax. A combination of distortionary unit (or yield) tax and timber tax can also be used to collect the tax revenue in a nondistortionary way. In the Hartman model, with forest amenity services as a public good, the optimal design consists of a nondistortionary tax and a Pigouvian tax, which adjusts the private rotation age to the socially optimal one. Now only the site productivity tax is nondistortionary, while unit, yield, timber, site value, and profit taxes generally serve as corrective Pigouvian taxes. Finally, in the absence of a nondistortionary tax, if the marginal valuation of amenity services is nondecreasing with the age of forest stand, a combination of unit (or yield) and timber taxes can be used for both tax revenue collection and Pigouvian correction. FOR. SCI.49(4):596–607.
Market Participation and Willingness to Pay for Environmentally Certified Products
Authors: Jensen Kim , Jakus Paul M. , English Burton , Menard Jamey
Published: April 2024

The purpose of this study is to ascertain (1) consumers' willingness to participate in a market for environmentally certified hardwood products, and (2) the ‘price premium’ consumers would be willing to pay for a certified oak shelving board. Further, we test how demographics influence market participation and the price premium. Results were obtained through a telephone survey of 811 Pennsylvania residents. Overall, 42.2% supported certification and were willing to pay higher prices for certified products, 45.5% supported certification but were not willing to pay higher prices, and 11.3% did not support certification regardless of costs. The profile of those most likely to participate in a certified wood product market includes nonhomeowners, female, college-educated, recyclers, and previous purchasers of environmentally labeled nonwood products. Among those supporting certification and willing to pay a premium, consumers were willing to pay $10.18 above the cost of an uncertified board ($28.80). For. Sci. 49(4):632–641.
A 2-Opt Tabu Search Procedure for the Multiperiod Forest Harvesting Problem with Adjacency, Greenup, Old Growth, and Even Flow Constraints
Authors: Caro Felipe , Constantino Miguel , Martins Isabel , Weintraub Andrés.
Published: April 2024

Because of environmental concerns, modern forest harvesting plans are being modified to address aesthetics and wildlife protection issues. In the literature, the most referenced are adjacency constraints with exclusion or “greenup” years. Also of interest are the concepts of old growth patch size and total old growth area restrictions. Typically, harvest blocks have been defined a priori. Recently, some have proposed a more complex approach in which basic cells are defined, and the decision-making process includes forming harvest blocks from these cells. This has been called ARM (Area Restriction Model). Until now, no successful exact method has been reported for large-scale ARM problems, leaving heuristics as a viable option. In this work we present a multiperiod harvest-scheduling ARM model with these spatial constraints. A tabu search procedure with 2-Opt moves (exchanging at most 2 units) was developed. For small size instances, the procedure found the optimal solution in most cases, and for a real-size problem an 8% optimality gap is provided.
Book Reviews: Forest Products and Wood Science: An Introduction. 4th Edition
Authors: Kelly Myron W.
Published: April 2024

This is the fourth edition of a book that first appeared more than 20 years ago and has been revised approximately every 7 years. This edition includes an additional author (Shmulsky) and the promotion of Bowyer to senior author. The overall quality has improved with each new edition and the current edition has reached another higher level of quality and content. This edition also has extended coverage of the composite wood panels that have attained market acceptance since the publication of the earlier editions.
Seasonal Photosynthesis in Fertilized and Nonfertilized Loblolly Pine
Authors: Gough Christopher M. , Seiler John R. , Johnsen Kurt H. , Sampson David Arthur
Published: April 2024

Net photosynthesis (Pn) of loblolly pine (Pinus taeda L.) foliage was monitored monthly in 14 yr old stands under near-ambient conditions over an entire year in upper and lower crowns and in both nonfertilized stands and stands receiving nutrient amendments for six consecutive years. Air temperature, humidity, vapor pressure deficit (VPD), photosynthetic photon flux density (PPFD), and plant water potential were monitored concurrently with Pn. Foliar nitrogen (N) concentration was also monitored. The effect of fertilization on Pn was inconsistent and generally not significant. Rates were consistently higher in the upper crown compared to the lower crown primarily due to variable light intensity. Multiple linear regression analysis shows that PPFD and VPD explain between 56% and 64% of the variability in foliar Pń, depending on the treatment. Little or no correlation between foliar N concentration and Pn was found, despite greater N concentrations in fertilized foliage, suggesting that fertilization does not enhance the photosynthetic capacity of loblolly pine foliage over the long term. Substantial amounts of carbon were fixed on measurement days during the winter season, even after freezing nights. Predicted light response curves indicate that foliar photosynthetic capacities are similar year-round, and gross primary productivity estimates (GPP) indicate that over 20% of the annual carbon fixation occurred during the nongrowing season. FOR. SCI. 50(1):1–9.
Optimal Harvest Strategy for Slash Pine Plantations: The Impact of Autocorrelated Prices for Multiple Products
Authors: Gong Peichen , Yin Runsheng
Published: April 2024

Using the management regimes of slash pine plantations in Georgia as an example, this article examines the impact of serially correlated prices for multiple outputs on harvest decision and financial performance. A stochastic dynamic programming model is formulated to derive the optimal harvest strategy numerically. While the general rule remains to harvest when the observed stumpage prices are greater than the reservation prices, our results show that there exist multiple pairs of reservation prices at each stand age, and these reservation prices cannot be reduced to a single one. This is in contrast to cases where prices are independent over time. Intensive silvicultural practices (e.g., herbicide use and fertilization) can reduce the reservation price and the variance of the financial return, but push up the mean return of a plantation project. Simulations with alternative price processes reveal that ignoring price uncertainty or price autocorrelations results in lower expected level but greater variability of the financial return and thus reduces investments by risk-averse investors. FOR. SCI. 50(1):10–19.
Efficiency of Seedlings and Rooted Cuttings for Testing and Selection in Pinus taeda
Authors: Isik Fikret , Li Bailian , Frampton John , Goldfarb Barry
Published: April 2024

Predicted genetic gains of polymix, cloned polymix, full-sib and cloned full-sib testing and selection options for a breeding population were estimated for Pinus taeda L. Heritabilities for volume from the clonal testing were considerably greater than the heritabilities from the seedling testing. Cloned options had higher expected genetic gains than seedling options, even after adjusting for their longer breeding cycles and higher cost of testing. This was mainly due to higher genetic gains from within-family selection of the cloned testing options. Adjusted genetic gain from within-family selection of polymix and cloned polymix were 0.27 and 0.36% per year, respectively. Increasing the number of ramets per clone did not increase the genetic gain, but gain was sensitive to the clone selection ratio within families. When the number of trees tested per family was fixed at 90 trees, all clone/ramet combinations gave greater within-family gains than the seedling option. A complementary breeding strategy consisting of polymix breeding for estimation of general combining ability and clonal selection from clonally replicated full-sib families appears to be more efficient for loblolly pine improvement than the currently used seedling-based testing system. For. Sci. 50(1):44–53.
An Assessment of Canopy Stratification and Tree Species Diversity Following Clearcutting in Central Appalachian Hardwoods
Authors: Brashears Mark Benjamin , Fajvan Mary Ann , Schuler Thomas M.
Published: April 2024

On high quality growing sites in West Virginia, shade intolerant tree species have increased in importance in third-generation forests following clearcutting. We investigated the effect of tree species canopy position on the Shannon-Weiner Diversity Index (H′), Pielou's evenness index (E), and species richness (S) using a chronosequence of 13 clearcuts. Two to 26 yr after clearcutting, tree species diversity significantly decreased from 2.07 to 1.83, and evenness decreased from 0.80 to 0.71 while species richness was maintained. As the number of years since harvesting increased, the importance value of oaks (Quercus L.), hickories (Carya Nutt.), American beech (Fagus grandifolia Ehrh.), sugar maple (Acer saccharum Marsh.), and black birch (Betula lenta L.) decreased while the importance of yellow-poplar (Liriodendron tulipifera L.) increased. In these mixed-species stands with stratified canopies, species importance in overstory versus understory canopy layers was the best indicator of competitive success during stem exclusion. Second-generation forests that had almost equal representation of overstory sugar maple and yellow-poplar prior to harvesting had 43% yellow-poplar and 13% sugar maple overstory importance 22–26 yr after harvest. Forty-five percent of the dominant crown class stems and 54% of the codominant class were yellow-poplar. While sugar maple was also an important (13%) overstory species overall, it had no dominant and few codominant stems and over 30% importance as overtopped trees and in the understory. As these stands progress through the stem exclusion stage, richness and measures of diversity may continue declining as yellow-poplar basal area increases. FOR. SCI. 50(1):54–64.
Tree Size and Drought Affect Ponderosa Pine Physiological Response to Thinning and Burning Treatments
Authors: Skov Kjerstin R. , Kolb Thomas E. , Wallin Kimberly F.
Published: April 2024

Thinning and burning treatments based on presettlement (prior to Euro-American settlement) stand conditions have been proposed for improving the vigor and growth of Pinus ponderosa. No study has examined effects of different levels of such thinning treatments on tree water, carbon, and nitrogen relations, or compared effects between postsettlement (trees established after Euro-American settlement) and presettlement (established before Euro-American settlement) trees. We investigated responses of presettlement and postsettlement trees to three levels of thinning and burning (unthinned/unburned control, light thinning/burning, heavy thinning/burning) over 2 yr that differed in precipitation in northern Arizona. Both thinning treatments consistently increased predawn water potential of both tree sizes compared with the control. Effects of thinning on leaf gas exchange varied between tree sizes and measurement times. Thinning increased net photosynthetic rate and stomatal conductance only when soil water availability was lowest, and increases were greater for postsettlement than presettlement trees. In contrast, thinning had no effect on foliar nitrogen concentration.Our results suggest greater positive effects of restoration thinning on tree water and carbon relations for postsettlement versus presettlement trees, and under drought versus nondrought conditions. Photosynthetic response to thinning in old trees may be constrained by physiological factors associated with large size such as low soil-to-leaf hydraulic conductance. FOR. SCI. 50(1):81–91.
Stand Productivity and Development in Two Mixed-Species Spacing Trials in the Central Oregon Cascades
Authors: Garber Sean M. , Maguire Douglas A.
Published: April 2024

Two mixed-species spacing trials were established in central Oregon to test the effects of species composition and initial spacing on stand growth, yield, and structural development. One trial was composed of Pinus contorta Dougl. ex Loud. and Pinus ponderosa Dougl. ex Laws. and the other Abies grandis (Dougl. ex D. Don) Lindl. and P. ponderosa. Spacing, species composition, and age all had large influences on standing volume and periodic annual growth. In both studies, standing volume and periodic annual increment decreased with increasing spacing. In mixed plots, the least shade tolerant species had the fastest early growth rates, while the more shade tolerant species had the slowest. Over time, initial differences in volume growth rates among plots of different species composition decreased. Relative yields in mixtures of P. contorta and P. ponderosa indicated no yield benefits. Mixtures of A. grandis and P. ponderosa, however, resulted in relative yield totals greater than one at all spacings. Spacing and species composition play an important role in stand production and development, and mixtures can yield similar if not more volume than pure stands of the higher yielding species at some spacings and stages of stand development. FOR. SCI. 50(1):92–105.
Exploring the Relationships Among Canopy Structure, Stand Productivity, and Biodiversity of Temperate Forest Ecosystems
Authors: Ishii Hiroaki T. , Tanabe Shin-ichi , Hiura Tsutom
Published: April 2024

Impacts of human activity on forest ecosystems are most pronounced in the temperate region. Simplification of stand structure has resulted in diminished ecosystem function and biodiversity decline, raising much debate over future management policies. Ecosystem functions and biodiversity may be enhanced by managing forests for increased structural complexity. However, processes that determine relationships among structural complexity, ecosystem functions, and biodiversity of forest ecosystems remain unclear. In this review, we present examples of studies conducted at two canopy research facilities located in different types of temperate forest to illustrate that structural complexity of forest canopies enhances stand productivity and biodiversity: (1) development of structurally complex canopies comprising various tree species enhances stand productivity by promoting complementary resource utilization among species through spatial, physiological, and temporal differentiation; and (2) development of complex canopy structure enhances biodiversity of canopy-dwelling organisms by creating a resource-rich habitat. These ecological observations stress the importance of including three-dimensional structural attributes of forest canopies in management plans and silvicultural prescriptions that aim to maintain ecosystem functions and biodiversity. FOR. SCI. 50(3):342–355.
Crown Cover Is Correlated with Relative Density, Tree Slenderness, and Tree Height in Lodgepole Pine
Authors: Rudnicki Mark , Silins Uldis , Lieffers Victor J.
Published: April 2024

The objective of this study was to investigate the relationship between tree height, bole slenderness, and relative density with crown shyness (crown interstitial space) in even-aged lodgepole pine. In 10 lodgepole pine stands in Alberta, Canada, ranging in height from 5.6 to 22.1 m, 9–23 triangular plots were established. A plot consisted of three trees that formed the corners of the triangle; all plots were at theoretical crown closure. Within each triangle, the percentage crown closure (% CC) was related to the mean height, slenderness coefficient (SC, tree height/diameter), and relative density (RD) of the trees that defined the triangle. Within the stands less than 12 m in height, % CC was positively correlated with RD. Within most of the stands greater than 15 m, % CC was negatively correlated to SC. Mean % CC declined with increasing stand height. Results suggest that RD is strongly related to % CC in short stands but as trees grow in height, biomechanical issues related to stem form (i.e., SC) probably play a large role in determining the amount of canopy coverage. We suggest that taller trees with high SC are more flexible, resulting in intense crown collisions, crown abrasion, and crown shyness. FOR. SCI. 50(3):356–363.
Forest and Rangeland Ecosystem Condition Indicators: Identifying National Areas of Opportunity Using Data Envelopment Analysis
Authors: Hof John , Flather Curtis , Baltic Tony , King Rudy
Published: April 2024

This article reports the methodology and results of a data envelopment analysis (DEA) that attempts to identify areas in the country where there is maximum potential for improving the forest and rangeland condition, based on 12 indicator variables. This analysis differs from previous DEA studies in that the primary variables are measures of human activity and indicators of forest and rangeland condition in place of the traditional economic inputs (costs) and outputs. It also involves a different (ecological) production process than traditional DEA analyses, and a statistical preanalysis is developed and applied to homogenize the large and highly diverse landscape where this ecological production process takes place for the purposes of the DEA. It is concluded that, based on this analysis, there are opportunities to improve the forest and rangeland condition without reducing the amount of human activity, but not over large areas, only for some indicators, and typically not for a large number of indicators in the same place. This means that large-scale improvements in environmental condition across many indicators may often not come about without a reduction in human activity. FOR. SCI. 50(4):473–494.
Long-Term Soil Responses to Site Preparation Burning in the Southern Appalachians
Authors: Knoepp Jennifer D. , Vose James M. , Swank Wayne T.
Published: April 2024

The mixed oak–pine ecosystems in the southern Appalachians are in decline because of a combination of drought and southern pine-beetle infestation. A commonly applied prescription for restoration of these degraded sites has been to fell all vegetation, allow it to dry, and conduct a site-preparation burn. However, there is little information on the mid- and long-term influences of this prescription on nutrient cycling. The fell-and-burn treatment was applied to three mixed oak–pine stands in the Nantahala National Forest in western North Carolina. Each stand had an untreated control area. Our objective was to determine the effects of this treatment on soil nutrient availability and potential nutrient loss. Exchangeable soil cations, pH, total carbon (C), and total nitrogen (N) were measured before and periodically for 5 years after treatment. Nitrogen transformations and nutrient availability in soil solution and in a stream draining one site were measured before and periodically for 3 years after burning. Exchangeable calcium and magnesium concentrations, soil pH, and N availability increased after treatment. There was no treatment effect on total soil C or N. Nitrogen mineralization rates were greater on burned versus control plots in 50% of the posttreatment measurements. This treatment increased nutrient availability and, although a significant amount of total site N was lost, there were no adverse effects on total soil nutrients or water quality. FOR. SCI. 50(4):540–550.
Simulating the Effect of Landscape Size and Age Structure on Cavity Tree Density Using a Resampling Technique
Authors: Fan Zhaofei , Lee Stephen S. , Shifley Stephen R. , Thompson III Frank R. , Larsen David R.
Published: April 2024

Cavity-tree density (CTD) is an important indicator of habitat quality for cavity-dependent wildlife. However, the abundance of cavities and cavity trees can vary dramatically, even among trees or stands with similar attributes. This uncertainty can make it difficult to expand stand-levelestimates of cavity abundance to large landscapes, although it is often desirable to do so. This limits the utility of CTD as a measure of habitat quality. We use a resampling method (statistical bootstrap) to construct a set of regression models to predict CTD based on landscape age structureand landscape size. The estimated regression coefficients are highly variable (in terms of the adjusted R2 and root mean square error) for landscapes <100 ha, but the models perform well for larger landscapes. We test the regression models using an independent data set from theMissouri Ozark Forest Ecosystem Project (MOFEP) and find that the mean relative error (RE) when predicting CTD for landscapes between 300 and 4,000 ha is less than 10%. Both the size (in hectares) of the landscape and the stand age-class components affect RE; but RE decreases with increasinglandscape size in a consistent and quantifiable manner. For Ozark landscapes ≥100 ha, knowledge of the proportion of the area in the seedling/sapling, pole, sawtimber, and old-growth age classes can be used to readily estimate the number of cavity trees and how that number will change ifthe landscape age structure is altered. FOR. SCI. 50(5):603–609.
Sustainability of Timber Supply Considering the Risk of Wildfire
Authors: Armstrong Glen W.
Published: April 2024

The boreal mixedwood forest of Alberta, Canada is an important timber-producing region subject to highly variable annual disturbance by wildfire. Existing timber supply models do not adequately capture the variation in annual area burned. This article presents a procedure to evaluatethe joint effects of harvest levels and wildfire on the sustainability of timber harvest. A Monte Carlo simulation model is developed that incorporates timber harvesting, forest fires, and replanning. The output of the model consists of projected distributions of sustainable harvest levelsgenerated by a linear programming-based timber supply model in response to specified harvest volumes and randomly generated burn areas. Because of the highly variable nature of the fire regime, it is difficult or impossible to set a harvest level that is perpetually sustainable with completecertainty. An alternative definition of sustainability is developed incorporating probabilities and time. At any point in time, a harvest level is considered sustainable if the probability of the harvest level exceeding the annual allowable cut is less than an acceptable level. FOR. SCI. 50(5):626–639.
Book Reviews: Forests in a Market Economy
Authors: Zhang Daowei
Published: April 2024

Those of us who teach senior undergraduate and graduate level forest economics courses have often been frustrated with the fact that there is no good textbook for these courses. The publication of this book may ease some of the frustration. Moreover, as the book title implies, it can serve as a background and research guide for forest economists in studying the role of forests in a market economy.
The Two-Stage Method for Measurement Error Characterization
Authors: Canavan Sean J. , Hann David W.
Published: April 2024

A measurement error (ME) is a component of any study involving the use of actual measurements, but is often not recognized or is ignored. The consequences of ME on models can be severe, affecting estimates of tree and stand attributes and model parameters. Although correction methods do exist for countering the effects of ME, the use of these methods requires knowledge of the distribution of the errors. A new method for modeling error distributions, called the two-stage error distribution (TSED) method, is presented here. This method is compared with traditional methods for error modeling through an example using diameter and height ME. Comparisons between the fitted error distribution surfaces and the empirical error surface are based on a dissimilarity measure. The results indicate that the TSED method produces a much more accurate and precise characterization of the ME distribution than do traditional methods when a high percentage of errors is identical. In other cases, the TSED method works as well as the most accurate form of the traditional method. The TSED method is also expected to perform better at characterizing asymmetric distributions. It is therefore more adaptable than traditional methods and is being proposed for error modeling in the future. FOR. SCI. 50(6):743–756.
Coarse Woody Debris in Managed Central Hardwood Forests of Indiana, USA
Authors: Jenkins Michael A. , Webster Christopher R. , Parker George R. , Spetich Martin A.
Published: April 2024

We evaluated the volume of down deadwood (DDW) and the basal area of standing deadwood (SDW) from a chronosequence of 110 silvicultural openings and 34 mature stands (72–105 years old) across three Ecological Landtype Phases (ELTP; wet-mesic bottomlands, mesic slopes, and dry-mesic slopes) in southern Indiana, USA. The volume of DDW decreased with increasing opening age and was lower in clearcuts than in group-selection openings. Openings on mesic slopes and bottoms contained greater volumes of DDW than openings on dry-mesic slopes. Regardless of age and ELTP, openings contained low volumes of highly decayed DDW. The volume of small-diameter DDW decreased rapidly with increasing stand age across all three ELTPs. Mature stands contained low total volumes of DDW (maximum of 22.4 ± 5.1 m3 ha−1) and low volumes of both highly decayed and large-diameter DDW. Most of the dead trees in silvicultural openings were small diameter and did not contribute significantly to DDW volume. SDW basal area was very low in mature stands (maximum of 1.4 ± 0.5 m2 ha−1), suggesting that little mortality has occurred. Our results suggest that even and uneven-aged silviculture in hardwood forests have differing impacts on the volume and distribution of coarse woody debris (CWD). In addition, the mature stands that dominate forests across much of the Central Hardwood Region of the eastern United States contain relatively little CWD compared to younger and old-growth stands. FOR. SCI. 50(6):781–792.
Photosynthetic and Water Use Efficiency Responses to Diffuse Radiation by an Aspen-Dominated Northern Hardwood Forest
Authors: Rocha Adrian V. , Su Hong-Bing , Vogel Christoph S. , Schmid Hans Peter , Curtis Peter S.
Published: April 2024

Clouds can exert strong effects on ecosystem CO2 and water vapor fluxes and may be important determinants of terrestrial primary production. We used three years of eddy-covariance and meteorological data from an aspen-dominated northern hardwood forest in Michigan to investigate how canopy photosynthesis (P), evapotranspiration (E), and water use efficiency (WUE) responded to changes in cloud cover, or the proportion of diffuse (If) to total (It) photosynthetically active radiation (PAR). Canopy quantum efficiency (the initial slope of the P versus PAR response curve) increased with increasing cloud cover, but both midday canopy P and canopy photosynthetic potential (the asymptote of the P versus PAR response curve) were greatest under partly cloudy skies (If/It = ∼0.57). Midday canopy E decreased and midday canopy WUE increased with increasing If/It. The relationship between canopy P and cloud cover varied with soil moisture. Canopy P was insensitive to changes in soil moisture under overcast skies (If/It > 0.70), whereas under clearer skies, canopy P was lower during periods of low compared to high soil moisture. These results further our understanding of cloud cover effects on canopy physiological processes and will aid in more accurate assessments of forest responses to climatic change. FOR. SCI. 50(6):793–801.