bluuebunny/crossref_metadata_2025 huggingface dataset:
Sapwood Area as an Estimator of Leaf Area and Foliar Weight in Cherrybark Oak and Green Ash
Authors: Meadows James S. , Hodges John D.
Published: April 2024

The relationships between foliar weight/leaf area and four stem dimensions (dbh, total stem cross-sectional area, total sapwood area, and current sapwood area at breast height) were investigated in two important bottomland tree species of the southern United States, cherrybark oak (Quercus falcata var. pagodifolia Ell.) and green ash (Fraxinus pennsylvanica Marsh.). In all models tested and for both species, total sapwood area was consistently more highly correlated with foliar weight and leaf area than were the other three measures. However, there was little difference in accuracy among simple linear, multiple, and nonlinear models that used total sapwood area to predict either foliar weight or leaf area. Accuracy was improved slightly through the addition of total height and live crown ratio to the linear model. Foliar weight of both species was best described as a function of total sapwood area and live crown ratio (r2 = 0.97, n = 16 for both species). Leaf area of cherrybark oak was best described as a function of total sapwood area, total height, and live crown ratio (r2 = 0.96, n = 16), whereas leaf area of green ash was best described as a nonlinear function of total sapwood area (r2 = 0.95, n = 16). In contrast with other studies on upland oaks in relatively cool climates, we found that current sapwood area was only a fair estimator of foliar weight and leaf area in cherrybark oak and was a poor estimator in green ash. These results lead to the speculation that more of the sapwood than just the most recent one or two growth rings may be active in water conduction in bottomland species in warm climates. Specific leaf area was highest in the lower crowns of trees of both species and was highest among trees of the lower crown classes. Although based on a limited sample size of four trees per crown class per species, we found that the vertical distribution of foliage within the crown differed among crown classes in both species. Most of the foliage on dominant and codominant trees of both species was concentrated in the upper one-third of the crown, with only a very small proportion of the foliage in the lower one-third of the crown. Intermediate and overtopped cherrybark oaks and intermediate green ash trees had a more even distribution of foliage throughout their crowns, while the foliage of overtopped green ash trees was highly concentrated in the lower one-third of the crown. The leaf area:sapwood area ratio did not differ significantly among crown classes in either species, but averaged 0.67 m2 cm-2 in cherrybark oak and 0.24 m2 cm-2 in green ash. FOR. SCI. 48(1):69–76.
Comparing Fixed- and Variable-Base-Age Site Equations Having Single Versus Multiple Asymptotes
Authors: Cieszewski C.J.
Published: April 2024

Site equations compute values of a variable Y as a function of both variable t and a value of the variable Y = Y0 measured at an arbitrary t = t0. For example, the plant size (Y) can be defined as a function of both age (t) and a reference size (Y0) measured at the base age t0. The base age can be implicit (i.e., implied but hidden), as in fixed-base-age equations [e.g., Y = f(t, S), where S is Y at t = 50], or explicit (i.e., readily exposed and changeable), as in dynamic equations [e.g., Y = f(t, t0, Y0)]. Using as the main criterion the ability of an equation to generate concurrent polymorphism and multiple asymptotes, I compare a fixed-base-age height growth site equation with several dynamic equations, derived through the traditional and the Generalized Algebraic Difference Approaches. The comparison leads to conclusions about desirable model properties, the methodologies of derivations, and expected outcomes of the different methodologies. The conclusions suggest that the ability to simulate concurrent polymorphism and multiple asymptotes is an important property of site equations that should be considered during modeling various growth trends. Furthermore, the conclusions suggest that both algebraic difference approaches are more parsimonious and robust than the fixed-base- age approaches. The Generalized Algebraic Difference Approach can increase model usefulness considerably through derivation of more complex equations that can achieve more desirable properties. FOR. SCI. 48(1): 7–23.
The Ratio of Live Crown Length to Sapwood Area as a Measure of Crown Sparseness
Authors: Maguire Douglas A. , Kanaskie Alan
Published: April 2024

Leaf area density is a biologically appealing index of forest tree health because it can provide an assessment of foliage loss or retention; however, it is difficult to measure directly. In contrast, the ratio of crown length to sapwood area (CL:SA) is quite amenable to objective field measurement, and could be interpreted as an index of crown sparseness. CL:SA was computed for Douglas-fir trees from 70 plots covering a range in average size, stand density, site quality, and crown condition in the Oregon Coast Range. When expressed as cm:cm2, the index ranged from 2 to 100 for individual trees and from 2 to 11 for plot averages based on the 200 largest trees per ha. In general, individual trees with a high CL:SA had a lower relative height within the stand. The index also increased with increasing severity of needle loss on sites where Swiss needle cast (SNC) is causing premature loss of foliage. After correcting for stand density and stand age, plot basal area growth increased significantly with a decrease in plot average CL:SA across a gradient in Swiss needle cast severity. CL:SA has strong potential for discriminating effectively among stands with varying degrees of foliage loss and growth reduction due to other disturbances as well, such as air pollution and defoliating insects. FOR. SCI. 48(1):93–100.
The Effectiveness of Stand-Level and Landscape-Level Variables for Explaining Bird Occurrence in an Industrial Forest
Authors: Hagan John M. , Meehan Amy L.
Published: April 2024

We evaluated the effectiveness of habitat variables derived at two spatial scales for explaining the presence or absence of 20 bird species at 363 point count stations in an extensive industrial forest in Maine. Sixteen stand-level (microhabitat) and seven landscape-level (within 1 km radius, or 3.14 km2) variables were used in stepwise logistic regression models to evaluate the relative roles of these two spatial scales for explaining each species' occurrence at a point count station. Species were classified as either early-successional (n = 6) or late-successional (n = 14) species for analysis. Three regressions were run for each of the 20 species: (1) stand variable only, (2) landscape variable only, and (3) stand and landscape variables combined. Regression models that included only stand-level variables averaged significantly higher model concordance scores than regression models that included only landscape variables. For 17 of 20 species, regressions that included only stand-level variables better explained the presence or absence of a species at a point than did regression that included only landscape-level variables. The presence of two species was better explained by landscape variables, and the presence of one species could not be explained by either stand- or landscape-level variables. Because many variables were positively associated with presence of some species and negatively associated with other species, management for particular stand- or landscape-level features must be preceded by a determination of which species are more important to conserve. FOR. SCI. 48(2):231–242.
Avian Habitat Relationships at Multiple Scales in a New England Forest
Authors: MacFaden Sean W. , Capen David E.
Published: April 2024

Habitat selection by birds is a complex phenomenon that varies by species and ommunity. Some birds select habitat according to specific combinations of microhabitat characteristics, which pertain to the structure and composition of site-specific vegetation. Recently, however, habitat selection studies have shifted from site-specific characteristics to consideration of coarser environmental scales. We examined habitat relationships for 31 bird species in the White Mountain National Forest at a series of scales from microhabitat (fine scale) to the landscape (coarse scale). Relative abundance data were collected through 10 min. point counts at 360 points organized into 15 transects. Habitats sampled included a diversity of forest-cover types (deciduous to coniferous) and management strategies (wilderness to clearcuts). Species-specific logistic regression models based on subsets (183 and 48 points) of the original dataset corroborated the historical focus on microhabitat, but models including other scales indicated that some birds respond to coarser scale environmental characteristics. These results also supported the premise that some birds respond to multiple environmental scales. Community gradient descriptions, based on anonical correspondence analysis (CCA), supported results of logistic regression, indicating that microhabitat constituted the most important level followed by lesser, but significant, contributions from other scales. Through species-environment biplots, CCA also effectively illustrated avian habitat selection as a multiple-scale phenomenon, showing the hierarchical organization of landscape components and how they affect the spatial distribution of bird communities. FOR. SCI. 48(2):243–253.
Salamander Abundance and Amphibian Species Richness in Riparian Buffer Strips in the Oregon Coast Range
Authors: Vesely David G. , McComb William C.
Published: April 2024

Logging and other forest practices are widely reported to be a threat to some amphibian populations in the Pacific Northwest. Riparian buffer strips are one conservation measure that may benefit amphibians in managed forests. However, few amphibian surveys have been conducted in buffer strips. We compared total salamander abundance, amphibian species richness, and sampling proportions for five species of salamanders between 17 managed stands and 12 unlogged, streamside forests in the Coast Range of western Oregon. We also identified relationships between buffer strip width and salamander population indices. Surveys conducted on 20 × 40 m plots demonstrated that torrent salamanders (Rhyacotriton spp.), clouded salamanders (Aneides ferreus), Dunn's salamanders (Plethodon Dunni), western red-backed salamanders (Plethodon vehiculum), total salamander abundance, and amphibian species richness were sensitive to forest practices in riparian areas. We conclude that riparian buffer strips are a useful habitat management strategy for several salamander species. However, buffer strip widths currently required by state forest practices regulations may not be adequate to prevent local declines in the diversity of amphibian communities. FOR. SCI. 48(2):291–297.
Bird Use of Forest Structural Classes in Grand Fir Forests of the Blue Mountains, Oregon
Authors: Sallabanks Rex , Riggs Robert A. , Cobb Lynda E.
Published: April 2024

We sampled breeding birds in 83 stands in the Blue Mountains, northeastern Oregon, 1994–1996, to describe bird use of forest structural classes in grand fir (Abies grandis) forests. We classified stands, based on basal area in different tree-size categories, into six forest structural classes: (1) stand initiation (SI); (2) stem exclusion, open canopy (SEOC); (3) stem exclusion, closed canopy (SECC); (4) understory reinitiation (UR); (5) young forest, multistory (YFMS); and (6) old forest, multistory (OFMS). Most species were detected in all structural classes, but slightly more than onethird of species analyzed (13 of 38) differed in abundance among structural classes (P < 0.004). Cluster analysis, based on structural attributes measured in each stand and weighted by avian abundance, grouped birds with similar habitat associations and allowed us to identify “non-SI associates,” “SI associates,” “structural class generalists,” and “mature forest associates.” We did not identify any species that could be considered strictly “OFMS associates.” With the exception of some SI associates, such as the mountain bluebird (Sialia currucoides) and house wren (Troglodytes aedon), we found little evidence of structural class specialization by birds. In grand fir forests of the Blue Mountains, ecologists and managers should focus on understanding how specific silvicultural prescriptions influence structural attributes that are correlated with avian abundance, rather than on stand age per se. FOR. SCI. 48(2):311–321.
Roost Site Characteristics of Northern Spotted Owls in the Nonbreeding Season in Central Washington
Authors: Herter Dale R. , Hicks Lorin L. , Stabins Henning C. , Millspaugh Joshua J. , Stabins Amy J. , Melampy Larry D.
Published: April 2024

To evaluate habitat important to northern spotted owls (Strix occidentalis caurina) away from the nest stand, we used radio telemetry to locate adult owls at diurnal roosts during the nonbreeding season (September 1–March 15, 1994–1997). We recorded physiographic variables and measured within-stand structural characteristics within nested circular plots centered on roost trees. We then compared owl use plots to random plots selected within suitable habitat and inside the approximated home ranges of the 14 (7 male, 7 female) owls studied. Spotted owls selected older forest over young forest. Owls selected sites lower in elevation, with larger tree diameter at breast height (dbh), fewer trees/ha, greater canopy cover, less cover of low shrubs, and fewer pieces of down wood than random locations. Females used old-growth and mature forest to a greater degree than males. Fewer trees/ha, less cover of low shrubs, and fewer pieces of down wood/transect best discriminated roost sites from random sites. These characteristics are not indicative of stand conditions thought to maximize prey density. Results may indicate selection of specific sites for roosting. However, because spotted owls opportunistically take prey from diurnal roosts and often roost in foraging stands, they may also be selecting for site characteristics that facilitate the capture of prey. FOR. SCI. 48(2):437–444.
Nonconstant Risk Attitudes and Timber Harvesting
Authors: Uusivuori Jussi
Published: April 2024

This article explores the effects of risk attitudes on the harvesting behavior of forest landowners. In particular, the effects of changing risk behavior on the forest owners' optimal harvesting decisions are studied under timber price uncertainty. With a theoretical model introducing an endogenous risk premium and addressing nonconstant risk attitudes, it is shown how the commonly predicted increase of wealth among nonindustrial private forest owners can have profound effects on harvesting behavior and timber supply from the private forest sector. For example, the model predicts that if landowners' aversion toward risk declines with increasing wealth, the standing timber stock in nonindustrial private forests will increase in the future, and the intensity of timber harvests declines. Contrary to now-popular timber harvest models, these results are obtained without dividing the benefits of forest into timber and nontimber ones. FOR. SCI. 48(3):459–470.
A Forest-Level Bucking Optimization System that Considers Customer's Demand and Transportation Costs
Authors: Arce Julio Eduardo , Carnieri Celso , Sanquetta Carlos Roberto , Filho Afonso Figueiredo
Published: April 2024

This article describes a system that deals with a forest-level bucking optimization problem considering customer's demand and transportation costs. The system was used to evaluate three scenarios: an observed medium-term forest harvesting scenario, with 32 stands harvested during one month, a simulated demand-oriented scenario and a simulated supply-oriented one. Data was obtained from Pinus taeda L. plantations located in southern Brazil. Various forest multiproducts with their respective local market prices were considered for modeling. The system has two main modules: the Cutting Pattern Generation (CPG) and the Global Bucking Optimization (GBO). In both modules, different algorithms are activated depending on the analyzed scenario (demand-oriented or supply-oriented). Additional biometric modules are also integrated into the system for height, taper, and volume calculations. In the demand-oriented scenario, the CPG exhaustively generates all possible cutting patterns for each diametric class in each stand, and the GBO, formulated as a Mixed Integer Linear Programming problem, optimizes the net revenue at forest level subject to constraints that consider bounds for timber volumes and maximum number of different multiproducts obtained in each stand. In the supply-oriented scenario, the CPG generates the Optimum Cutting Pattern through a heuristic algorithm that identifies the potential cuts to evaluate along the stem and a Dynamic Programming-based algorithm to determine the optimum combination of products that maximizes the stem profit, and the GBO calculates the net profit, summing up the profits per stem for each stand and sum of the stands. Illustrative examples and numerical results are given. FOR. SCI. 48(3):492–503.
Optimization of Land Use in Afforestation Areas Using Evolutionary Self-Organization
Authors: Strange Niels , Meilby Henrik , Thorsen Bo Jellesmark
Published: April 2024

This article presents a cellular automaton approach to the optimization of land use planning in afforestation areas. The case study deals with 110 ha of recently afforested land in Denmark. A modified two-dimensional automaton containing 2,345 active cells is used for optimizing the land use setup in this area. Four land use alternatives are considered: pasture, beech (Fagus sylvatica L.), Norway spruce (Picea abies [L.] Karst.), and oak (Quercus robur L.). The objective is to maximize a weighted sum of soil expectation value, scale-dependent costs, recreational value, and the value of structural variation. It is demonstrated that for this sort of problem, appropriately modified cellular automata may yield acceptable solutions within a comparatively low number of iterations. Furthermore, for a simplified hypothetical problem, it is shown that the cellular automaton approach was able to identify optimal solutions within reasonable time. FOR. SCI. 48(3):543–555.
Continuing Growth Response to Phosphate Fertilizers by a Pinus radiata Plantation over Fifty Years
Authors: Turner J. , Lambert Marcia J. , Humphreys F.R.
Published: April 2024

The period of growth response of forest plantations to phosphate fertilizer applications has been variable and difficult to predict. Significant growth responses by Pinus radiata (D. Don) to two different phosphate fertilizers, superphosphate and rock phosphate applied at 96 kg P ha-1 (previously reported by the authors) have continued for the 50 yr period since the fertilizers were initially applied in 1947. There have been no further fertilizer applications. At the end of the second rotation of 33 yr (50 yr after the fertilizer was applied), the growth and biomass of the trees were determined, together with soil and foliage chemical analyses, and comparisons made with those obtained earlier. The standing volume of the phosphate treatments was 430 m3 ha-1, an increase of 50% over the 287 m3 ha-1 in the untreated control. Soil total phosphorus concentrations were increased from 64 mg kg-1 in the control to 105 mg kg-1 and 134 mg kg-1 in the superphosphate and rock phosphate treatments, respectively, and have remained constant. The aboveground biomass of the treated plots was about 380 tonne ha-1 compared with 278 tonne ha-1 in the control. The single application of phosphorus has led to a significant change in site characteristics. The implications for forest management are that a relatively low application of fertilizer on some nutritionally poor sites changes the productive capacity of the site. FOR. SCI. 48(3):556–568.
Terrestrial Global Productivity
Authors: Jose Shibu
Published: April 2024

Terrestrial primary productivity has been a central focus of ecologists worldwide for the last three decades. The International Biological Program (IBP) of the early 1970s laid the foundation and provided a wealth of knowledge on the biological basis of productivity in different environments. However, there was little progress, until recently, in estimating productivity of large regions and biomes. The growing realization that productivity of terrestrial ecosystems is strongly affected by changes in climate and land-use patterns has prompted ecologists to translate ecological hypotheses derived from the local or stand level into continental or global scales. In recent years, policymakers also have focused their attention on terrestrial primary productivity because of the importance of land ecosystems as carbon sinks and their role in mitigating the impacts of rising atmospheric CO2. Hence, an effort in updating and synthesizing the current state of knowledge and research on global primary productivity should be appreciated. Through the publication of this book the editors have done a commendable job in bringing together the collective wisdom of 50 prominent ecologists in analyzing primary productivity from the canopy to global level and identifying gaps in our knowledge base.
Landscape Ecosystems of the Mack Lake Burn, Northern Lower Michigan, and the Occurrence of the Kirtland's Warbler
Authors: Walker Wayne S. , Barnes Burton V. , Kashian Daniel M.
Published: April 2024

The Kirtland's warbler (Dendroica kirtlandii Baird) is a federally endangered songbird that nests only in ecosystems dominated by young jack pine (Pinus banksiana Lamb.) in northern Michigan. Although considerable research has focused on the bird, comparatively little information is available on the specific landscape ecosystems occupied by the warbler. The 9,700 ha Mack Lake burn provided an opportunity to track the pattern of Kirtland's warbler occurrence in relation to the ecosystems of a highly diverse and productive area of its breeding range. Using a multifactor landscape ecosystem approach, two high-elevation and four low-elevation landform-level ecosystems were identified, described, and mapped. The spatial pattern of warbler occurrence over time was strongly mediated by the physical and biotic components of the ecosystems. During the first 3 yr of warbler occupation (1986–1988), the high-elevation landforms, characterized by relatively warm temperatures, moister, more fertile soils, and faster growing jack pines, supported 62% of the population. Thereafter, a major shift occurred to the low-elevation landforms. During the last 3 yr of record (1995–1997), the low-elevation landforms, characterized by colder temperatures, drier, less fertile soils, and slow-growing jack pines, supported 86% of the population. The juxtaposition of high- and low-elevation landforms, and the fine-scale ecosystem diversity within them, prolonged the duration of warbler occupancy beyond what would be expected in less heterogeneous conditions. As demonstrated here, the landscape ecosystem approach provides a sound, ecological framework for understanding patterns of Kirtland's warbler occurrence and for assisting managers in identifying appropriate management areas for the continued recovery of the species. FOR. SCI. 49(1):119–139.
Book Reviews: Integrated Public Lands Management: Principles and Applications to National Forests, Parks, Wildlife Refuges, and BLM Lands
Authors: Linehan Peter E.
Published: April 2024

The intense wildfire season of 2002 devastated hundreds of thousands of acres of forest lands in the western United States. A bigger impact in the public awareness came from the intense media attention on the large number of homes and buildings threatened as well as cities such as Denver, Colorado, and many small towns in New Mexico and Oregon. It would appear to be relatively easy to arrive at a consensus to deal with such a serious threat to the public welfare. Yet, as the intensely critical reaction to the Bush administration's relatively modest set of proposals to streamline administrative procedures and promote fuel load reductions with thinning and harvesting shows: there is no consensus on natural resource management policy on public lands. This book shows how federal natural resource management policies developed over time to meet the conflicting and changing desires of the public. While learning resource analysis and management techniques, readers can also see their history and justification.
Estimating and Validating Ground-Based Timber Harvesting Production Through Computer Simulation
Authors: Wang Jingxin , LeDoux Chris B.
Published: April 2024

Estimating ground-based timber harvesting systems production with an object-oriented methodology was investigated. The estimation model developed generates stands of trees, simulates chain saw, drive-to-tree feller-buncher, swing-to-tree single-grip harvester felling, and grapple skidder and forwarder extraction activities, and analyzes costs and productivity. It also measures the traffic intensity level of extraction machines across sites. The model components were validated using data from several independent field studies. The model was used to evaluate the interaction of stand variables, harvest treatments, machines, and extraction patterns. Using two main skid trails to harvest a block minimized traffic intensity. The model can be best used to evaluate alternative skidding configurations and their impact on cost, production, and traffic intensity. FOR. SCI. 49(1):64–76.
Estimating Stand Characteristics by Combining Single Tree Pattern Recognition of Digital Video Imagery and a Theoretical Diameter Distribution Model
Authors: Maltamo M. , Tokola T. , Lehikoinen M.
Published: April 2024

This article presents a new method combining pattern recognition of single trees and a theoretical diameter distribution to determine stand characteristics. The applied remote sensing material was digital video imagery. A super-resolution technique was used in order to improve the quality of the video imagery. Tree crowns were identified and crown areas segmented from the super-resolution image. After that, tree diameters were predicted using detected crown areas. However, only large trees (dbh >17 cm) could be recognized from digital video image. Therefore, the theoretical Weibull distribution was predicted to be able to also calculate the number of small trees (dbh <17 cm). The mean characteristics information needed for predicting the parameters of Weibull distribution was obtained from the resulting truncated distribution of large trees. The final estimate of the diameter distribution is a combination of these two parts.

The reliability of prediction of stand characteristics considered, i.e., number of stems, stand basal area, and volume was improved with the use of the theoretical diameter distribution model. However, these results should be considered preliminary, because they are based on a small validation data set. According to these results, especially the accuracy of the estimate of the number of stems was increased considerably. This improvement is important when simulating future stand development in forest management planning software packages. FOR. SCI. 49(1):98–109.
Comparison of Ground Sampling Methods for Estimating Canopy Cover
Authors: Williams Michael S. , Patterson Paul L. , Todd Mowrer H.
Published: April 2024

Knowledge of the canopy structure is essential to improving our understanding of forest structure. While numerous sampling techniques have been developed to estimate attributes of the forest canopy, these require either additional measurements or a sampling design and measurement techniques that differ substantially from the ones that are used to estimate more traditional forest attributes, such as basal area, number of stems, or volume. The root of the problem is that the sample element for a design that estimates canopy attributes is the tree crown, whereas the sample element is the bole for a design that estimates an attribute such as basal area. For example, if a fixed-area plot is used to estimate basal area, canopy cover cannot be estimated using the same design because a portion of the plot invariably is covered by the crowns of trees whose boles lie outside the plot boundary and would not be included in the sample under the standard sampling design. In this study, a technique called “morphing” is used to model the trees outside the plot boundary. For the purpose of comparison, the morphing technique is used to estimate canopy cover using data from a circular fixed-area plot, and this technique is compared with both dot count and line intersect sampling using a simulation study and two small forest populations. For the study, the populations were sampled using circular fixed-area plots with radii ranging from ρ = 3.05–6.10 m (10–20 ft) and line lengths ranging from L = 3.05–22.9 m (10–75 ft). For both populations, the bias of the canopy cover estimator derived from the morphing technique was negligible. The estimator based on line intersect sampling is design-unbiased, but it generally had a much larger variance than the one based on the morphing technique. The dot count method consistently had the highest variance. FOR. SCI. 49(2):235–246.
Simple Tests for Detecting Segregation of Major Genes with Phenotypic Data from a Diallel Mating
Authors: Zeng Wen , Li Bailian
Published: April 2024

Three simple statistical tests (the Bartlett test, the log-ANOVA test, and the Fain test) were investigated for detecting the segregation of major genes controlling a quantitative trait in half-diallel mating populations. Eight experimental diallel progeny populations of loblolly pine (Pinus taeda L.) from a breeding program were analyzed to detect major gene segregation for 6 yr tree height. The results from three simple tests indicated that there could be major gene segregation for 6 yr height in three diallels. Data with different degrees of major and polygenic effects were simulated with the same mating and field experimental design for further evaluation of these simple tests. Statistical powers of detection were assessed for a major gene with two alleles plus the polygenic background of general combining ability (GCA) and specific combining ability (SCA) effects. The robustness of methods to the presence of half-sib relationships, a skewed phenotypic distribution, and unbalanced data were evaluated. The Bartlett test was the most powerful, but was sensitive to half-sib relationship and skewness. The log-ANOVA test was as powerful as the Bartlett test, but was robust to half-sib relationship and skewness. The Fain test was less powerful but less sensitive to skewness than the Bartlett test. The major gene effect (percent of total phenotypic variance) and dominance level of the major gene were the two most important factors affecting the power of detection. The power for the Bartlett and log-ANOVA test increased with the increment of polygenic heritability. The ratio of dominance to additive variance for polygenic inheritance had little effect on the power for the Bartlett and log-ANOVA tests. The log-ANOVA test is the most desired simple test for detecting major gene segregation in a diallel population with half-sib structures. Simple tests can be used to screen breeding populations for major genes affecting tree growth, and the information can be useful to speed up traditional tree breeding programs. FOR. SCI. 49(2):268–278.
Predicting External Branch Characteristics of Planted Silver Birch (Betula pendula Roth.) on the Basis of Routine Stand and Tree Measurements
Authors: Mäkinen Harri , Ojansuu Risto , Niemistö Pentti
Published: April 2024

The aim of this study was to develop simultaneous models for external branch characteristics along the stem that could be applied as a part of a growth simulation system. Data were collected from planted pure stands of silver birch (Betula pendula Roth.) growing on abandoned agricultural land and forest sites of different fertility, with different stand density and age. The data were used to develop generalized linear variance component models for (1) crown ratio, (2) self-pruning ratio, i.e., height of the lowest dead branch divided by the height of the crown base, (3) number of living branches along the stem, (4) total number of branches, (5) diameter of the thickest branch, (6) diameters of smaller branches, and (7) branch angle. The independent variables of the models were restricted to those measured in forest inventories and used for forest management planning purposes. Even though there was bias in predicting some of the branch characteristics in the independent evaluation data set of silver birch, the behavior of the models was logical. No major additional bias was found when the models were applied to downy birch (Betula pubescens Ehrh.). The models provide a framework for predicting the development of wood quality and the possibilities of using silvicultural treatments to control branch characteristics. FOR. SCI. 49(2):301–317.
An Integer Programming Model to Optimize Resource Allocation for Wildfire Containment
Authors: Donovan Geoffrey H. , Rideout Douglas B.
Published: April 2024

Determining the specific mix of fire-fighting resources for a given fire is a necessary condition for identifying the minimum of the Cost Plus Net Value Change (C+NVC) function. Current wildland fire management models may not reliably do so. The problem of identifying the most efficient wildland fire organization is characterized mathematically using integer-programming techniques. This mathematical exposition is then solved using the LINGO optimization language. Sensitivity analysis is conducted on model inputs to demonstrate the flexibility of the model architecture. Further, the model is used to model budget constraints commonly faced by fire managers. FOR. SCI. 49(2):331–335.
Satellite Change Detection of Forest Harvest Patterns on an Industrial Forest Landscape
Authors: Sader Steven A. , Bertrand Matthew , Wilson Emily Hoffhine
Published: April 2024

Multiple dates of Landsat Thematic Mapper (TM) imagery were analyzed to compare a decade of forest harvest activity in northern Maine's industrial forest. Unsupervised clustering on three-date sequences of Normalized Difference Vegetation Index classified the harvest type and time period when change occurred. Problematic clusters were reclassified using the Normalized Difference Moisture Index, which improved the detection of light partial harvests. The procedure classified clearcuts and partial cuts in all time periods with at least 80% agreement with 250 reference sample points. Patch characteristics of the harvest areas revealed a shift from large clearcuts in the late 1980s and early 1990s to fewer and smaller clearcuts in the middle to late 1990s. By the late 1990s, large clearcuts (>40 ha) were eliminated, and partial cuts increased in size. Partial cuts affected more land area than did clearcuts in all time periods. Comparison of harvest patches between the two largest landowners in the study area revealed significant differences in the number and distance between clearcut harvest areas. The trends in decreasing clearcut harvesting practices over the past decade appear to have been influenced by forestry legislation, according to the results of this study and an independent report by the Maine Forest Service. The changing harvest patterns on the landscape were detectable on time-series satellite imagery. FOR. SCI. 49 (3):341–353.
Comparing Two Area Estimation Techniques for Established Surveys Using Remotely Sensed and Ground Data
Authors: Williams Michael S. , Patterson Paul L.
Published: April 2024

Estimates of the area of forest using remotely sensed and ground data can be derived using two distinctly different paradigms. The first, which will be referred to as the “tessellated population paradigm,” relies on the assumption that the area is divided into contiguous blocks that constitute an area frame. Inference is drawn using traditional finite population sampling methods. The other approach will be referred to as the point paradigm, which assumes that the sampling unit is a point on the ground. The estimators are derived assuming the number of ground plots in each remotely sensed category is random. The mechanisms that determine the variance of the estimators are different for both paradigms, with the variance of the point paradigm depending on the accuracy and size of each remotely sensed class, while the variance of the tessellated population paradigm depends predominantly on the fragmentation of the landscape in comparison with the size of the sampling unit. An analytical comparison of the estimators is not possible because of the difficulty associated with relating landscape fragmentation to the accuracy of the remotely sensed data. Thus, both estimators were tested by drawing samples from a series of artificial landscapes and satellite images using a plot configuration similar to the one used by the Forest Inventory and Analysis program of the United States. It is concluded that if the landscape is heavily fragmented and the accuracy is reasonably high, the point paradigm estimator is likely to have a smaller variance. The tessellated population estimators will usually have a smaller variance when the landscape has only a small degree of fragmentation. For the majority of the artificial populations studied, the estimator based on the tessellated population paradigm had the smallest variance. In situations where there would not be sufficient prior knowledge to determine which paradigm is superior or when the variance of both is expected to be about equal, the point paradigm is recommended because it is theoretically more tractable and easier to implement in the field. FOR. SCI. 49(3):392–401.
Estimation of Tree Height and Stem Volume on Plots Using Airborne Laser Scanning
Authors: Holmgren Johan , Nilsson Mats , Olsson Håkan
Published: April 2024

Airborne laser scanning has the ability to measure the vertical and horizontal structure of forest vegetation. The aim of this study is to investigate how measures derived from laser scanning data can be used in regression models for estimation of basal-area-weighted mean tree height and stem volume on 10 m radius field plots. Influence of laser scan angle on tree height estimation and on crown coverage area estimation is also investigated. The study area was located in southern Sweden (lat. 58°30′N, long. 13°40′E). The dominating tree species were Norway spruce (Picea abies L. Karst .), Scots pine (Pinus sylvestris L.) and birch (Betula spp.). Linear regression functions (R2=0.89–0.91) used to predict basal-area-weighted mean tree height had a Root Mean Square Error (RMSE) of 1.45–1.56 m, corresponding to 10–11% of average height. Scanning angle was not significant for estimation of basal-area-weighted mean tree height. Two regression models were used for prediction of stem volume. The first model (R2 = 0.90), with laser derived mean height together with laser derived crown coverage area as predicting variables, gave RMSE of 37 m3 ha-1, corresponding to 22% of average stem volume. The second model (R2=0.82), with laser derived tree height together with laser derived stem number as predicting variables, gave RMSE of 43 m3 ha-1, corresponding to 26% of average stem volume. The results implies that airborne laser scanning, if combined with a field sample, has potential of retrieving information with high spatial resolution (10 m radius plot) about tree height and stem volume for a forest area. FOR. SCI. 49(3):419–428.
Developing a Well-Behaved Dynamic Site Equation Using a Modified Hossfeld IV Function Y3 = (axm)/(c + x
m–1), a Simplified Mixed-Model and Scant Subalpine Fir Data
Authors: Cieszewski C.J.
Published: April 2024

I developed a dynamic height growth model by using a simplified form of mixed effects modeling and subalpine fir (Abies lasiocarpa [Hook.] Nutt .) stem analysis data. The new dynamic equation uses directly heights at any age to predict consistent heights (e.g., y2 = f(t2, t1, y1) ⇔ y1 = f(t1, t2, y2)) and f(t3, t1, y1) = f(t3, t2, f(t2, t1, y1))), and therefore constitutes compatible site index and height models in one common equation. The parameters for the model were estimated by analysis of fixed and random effects with corrections for first- and second-order serial autocorrelation. The correction for second-order autocorrelation was necessary to assure the model's proper representation of the data and to remove a seeming cross-sectional autocorrelation across different sites/series. Estimating the errors in site indices as random effects eliminated the effects of stochastic predictive variables. The proposed model has outperformed all other base-age specific and base-age invariant models in both the fit to the data and in its behavior during extrapolations. It also outperforms the model (developed on amabilis fir data) that is currently, operationally used for subalpine fir. The new model's advantages are parsimony, mathematical tractability, base-age invariance, and greater consistency in curvatures of the generated height-age trajectories. FOR. SCI. 49(4):539–554.
Comparison of Neural Networks and Statistical Methods in Classification of Ecological Habitats Using FIA Data
Authors: Liu Chuangmin , Zhang Lianjun , Davis Craig J. , Solomon Dale S. , Brann Thomas B. , Caldwell Lawrence E.
Published: April 2024

Two artificial neural networks (ANN) and three traditional statistical classification methods are used to classify Forest Inventory and Analysis (FIA) plots into six ecological habitats in the U.S. Northeast. Four variables (overstory and understory species composition, hardwood basal area percentage, and current FIA forest type) are identified from a list of available stand variables as the most important discriminating variables for habitat classification. The error matrix and accuracy indices are used to assess the classification accuracy of the models and to test the differences between the five classifiers. The ANN models (MLP and RBF) are superior to the traditional statistical methods such as linear discriminant analysis and minimum-distance classification. The classification accuracy of the ANN models is 90% or higher for overall classification, and exceeds 92% in five of the six habitat categories. The K-Nearest Neighbor (KNN) method classifies the six ecological habitats as accurately as the two neural network models. This study shows that the ANN models and KNN method have a great potential for the classification of ecological habitats using FIA data, due to their flexibility of modeling algorithms and robustness to the problems in FIA data such as non-Gaussian distributions, nonlinear relationships, outliers and noise in the data. For. Sci. 49(4):619–631.
Book Reviews: Applied Ecology and Natural Resource Management
Authors: Jenkins M.A.
Published: April 2024

The incorporation of ecological information is probably the most critical step in making decisions about the management of natural resources. However, because of the complexity of both ecological information and its potential application to management prescriptions, it is also among the most difficult tasks facing resource managers. There has long existed a divide between researchers, who are often searching for generality among ecological relationships, and managers, who seek specific information about the systems they manage. For managers, bridging this divide is critical to preserving biological diversity, ensuring sustainability, and meeting the resource needs of an ever-expanding population. For researchers who are interested in applied ecology, bridging this divide is critical if their efforts are to move from the journal page to real world applications within the field of resource management.
Risk-Aversion and the Short-Run Supply of Timber
Authors: Gong Peichen , Löfgren Karl-Gustaf
Published: April 2024

This article examines the effect of risk-aversion on the short-run supply of timber, when the harvest revenue is invested in a portfolio of a riskless and a risky asset. Assuming that the future stumpage price and the rate of return on the risky asset are independent and normally distributed, it is shown that the effect of risk-aversion on the optimal harvesting behavior depends on the sign of a marginal variance function. This shows the effect of a marginal increase in the harvest volume on the variance of the future wealth, evaluated at the optimal harvest-investment decision under risk-neutral preferences. If the marginal variance is negative, then risk-aversion increases harvest in the first-period. If it equals zero, then only high degrees of risk-aversion affect (increase) the harvest. Finally, if the marginal variance is greater than zero, then high degrees of risk-aversion increase the harvest, whereas low degrees of risk-aversion have the opposite effect. The result has implications for the analysis of the harvesting behavior of any renewable resources.
The Influence of Forest and Stand Conditions on Spruce Budworm Defoliation in New Brunswick, Canada
Authors: MacKinnon Wayne E. , MacLean David A.
Published: April 2024

The species composition of stands and surrounding forest have been suggested as important factors influencing the amount of spruce budworm (Choristoneura fumiferana [Clem.]) defoliation and, consequently, budworm-induced growth loss and mortality. We measured spruce budworm defoliation from 1989–1993 in 40 spruce (Picea sp.) and balsam fir (Abies balsamea [L.] Mill.) stands in north-central New Brunswick, Canada, and evaluated the influence of surrounding forest type (softwood, mixedwood), species group (balsam fir, spruce), and site quality (wet/nutrient poor, moist/nutrient rich) on defoliation. Surrounding forest type had a significant effect on the amount of defoliation in white spruce (Picea glauca [Moench] Voss) stands; stands in softwood forests sustained 11% more (P = 0.0485) defoliation than those in mixedwood. There was evidence that hardwood species have to be within, rather than surrounding, a spruce-fir stand to significantly influence defoliation. Site quality had a significant effect (P = 0.0039) on balsam fir defoliation, with stands on moist/rich sites sustaining 19% more defoliation than those on wet/poor sites. In softwood forest, white spruce stands sustained an average of 16% more defoliation than red-black spruce (Picea rubens Sarg.-Picea mariana [Mill.] B.S.P.) stands.
Time Trends in Genetic Parameters for Height and Optimal Age for Parental Selection in Scots Pine
Authors: Jansson Gunnar , Li Bailian , Hannrup Björn
Published: April 2024

Data used to estimate time trends in genetic parameters and the optimal age for parental selection were obtained from 13 Scots pine (Pinus sylvestris L.) progeny tests in southern Sweden. The final age at measurement was between 24 and 39 yr, corresponding to approximately half the rotation age in southern Sweden. Trees in each test have been measured for height 4–6 times, covering ages from 5 to 39 yr. Individual tree heritability for height averaged 0.16, and increased slightly over time, although there were differences among tests. The average additive coefficient of variation for height (CVA), which decreased with age, was 6.0% while the average nonadditive coefficient of variation (CVD) was 3.8% and did not show any significant trend over time. A model based on the natural logarithm of the ratio between the two ages at measurement was used to predict genetic age-age correlations. The efficiency of early selection was also examined, in an analysis considering total height at age 30 as the target trait. The optimal age for parental selection based on gain per unit time peaked at 11 yr, with a time lag for breeding of 10 yr. In the southern tests, the peak came some years earlier than in the northern tests. Selection efficiency based on present value with an interest rate of 5% showed the optimum at 11 yr.