bluuebunny/crossref_metadata_2025 huggingface dataset:
Stand-Scale Correspondence in Empirical and Simulated Labile Carbohydrates in Loblolly Pine
Authors: Sampson David A. , Johnsen Kurt H. , Ludovici Kim H. , Albaugh Timothy J. , Maier Chris A.
Published: April 2024

As investment into intensive forestry increases, the potential trade-offs between productivity and sustainability should be scrutinized. Because of their important role in internal carbon (C) budgets, labile C pools may provide a measure of the potential ability of trees and stands to respond to stress. We modified the process model BIOMASS to examine daily C budgets of midrotation nonfertilized and fertilized loblolly pine stands. We tested whether the absolute difference between daily simulated net canopy assimilation (GPP minus maintenance respiration) and our empirical estimates of production, or daily gross carbon balance, mimics the labile carbohydrate C pool. We compared this labile pool surrogate to independent, empirical analyses of total nonstructural (starch and soluble sugars) carbohydrates from an individual whole-tree analysis scaled to the stand level.Of particular interest, the simulated daily gross C balance indicated periods of carbon deficit during the growing season that lasted from 1 to 40 days. Simulated daily net C balance was met from labile C storage during these periods. Fertilized plots had similar time-period trends as the control plots, but exhibited a twofold increase in C assimilation and use. Simulated and empirical estimates of the labile carbohydrate pools displayed similar seasonal trends, although their correspondence depended on the time of year. Simulations indicated a winter/early spring “recharge” period; concentrations peaked at ~50 and ~60 mg C g biomass-1 in control and fertilized plots, respectively, in 1995. The overall correlation between predicted and empirical estimates was low to moderate (r = 0.51). The best agreement was with the empirical data from April through June as concentrations declined; however, predicted minimum concentrations (15 and 5 mg C g biomass-1 in control and fertilized plots, respectively) were lower, and obtained earlier in the year than the empirical data (~20 mg C mg biomass-1). These analyses quantify the strong extent that loblolly pine exhibits a buffered capacity to balance the C budget when current photosynthesis occasionally cannot meet daily C requirements. Further development of our approach may lead to a tool for analyzing potential risks associated with intensive forest management. FOR. Sci. 47(1):60–68.
Influence of Two Plant Growth-Promoting Rhizobacteria on Loblolly Pine Root Respiration and IAA Activity
Authors: Vonderwell J.D. , Enebak S.A. , Samuelson L.J.
Published: April 2024

A clearer understanding of factors contributing to inconsistency in seedling root growth promotion among nurseries has become important to managers as the commercial use of rhizobacteria in forest nurseries increases. To address why some bacterial strains increase root growth response while others do not, two separate experiments were conducted with loblolly pine (Pinus taeda L.) seedlings. Experiment one examined growth media. Seed were sown in either a hand-mixed peat:vermiculite:perlite (2:1:1, v:v:v) potting medum or a commercial medum—Promix® (1:1 peat:vermiculite). Seed were inoculated at sowing with an equal amount of either Bacillus subtilis strain LS211, B. subtilis strain INR7, or sterile distilled water. Seedling biomass, root length, root surface area, average root diameter, and root volume were measured at 6 and 12 wk after sowing. Growth promotion was variable and dependent on media and weeks since sowing. In a second experiment, root respiration rate and total root indole-acetic acid (IAA) content were quantified at 6 and 12 wk for seedlings grown in Promix®. In experiment two, strain INR7 decreased whole root system respiration by 22% and increased root biomass and root length compared to controls at 6 wk. Bacterial strain LS211 had no effect on root respiration. Furthermore, bacterial strain INR7 produced 1.7 times the total root IAA concentration of controls at 6 wk, whereas LS211 had no effect. Although cause and effect could not be tested, these studies suggest that root growth promotion is influenced by growth media and that IAA concentrations and root respiration rates are two physiological mechanisms correlated with rhizobacterial activity and growth promotion. FOR. SCI. 47(2):197–202.
Clarification of the Mirage Method for Boundary Correction, with Possible Bias in Plot and Point Sampling
Authors: Ducey Mark J. , Gove Jeffrey H. , Ståhl Göran , Ringvall Anna
Published: April 2024

While the mirage method of boundary overlap correction has been shown to be unbiased, an emphasis on the case of circular inclusion zones has led to an ambiguity in its presentation in much of the literature. We present a clarification of the method and show that its incorrect application leads to bias. We further show that depending on the method of slope correction, the potential for bias extends to variable radius plot sampling. Correct application of the mirage method has implications for when plots should be reflected, and how borderline trees should be handled on the reflected plots. FOR. SCI. 47(2):242–245.
Effects of Light Regimes on the Growth of Cherrybark Oak Seedlings
Authors: Guo Yanfei , Shelton Michael G. , Lockhart Brian R.
Published: April 2024

Light regimes vary significantly within small forest openings, ranging from full sunlight to total shade, and they may affect the establishment and early growth of oak seedlings. We designed modified shadehouses to simulate the complex light conditions within forest openings and tested the effects of daily photosynthetically active radiation (PAR), time of direct light exposure, and the ratio of direct light to day length (direct-sunlight ratio) on height, diameter, and periodic growth of cherrybark oak (Quercus pagoda Raf.) seedlings through 2 yr. Five treatments representing the time of exposure to direct sunlight were created: NO, NOON, MORNING, AFTERNOON, and FULL. Treatments significantly affected both the height and root-collar diameter of seedlings, especially during the second growing season. The direct-sunlight ratio was linearly related to periodic height growth for the NOON treatment but not related to height growth for the other treatments. However, periodic height growth in the AFTERNOON and FULL treatments was highly correlated to mean daily PAR. Maximum periodic height growth occurred at moderate daily PAR levels. This research showed that light conditions for maximum growth of cherrybark oak seedlings change through time, with adequate shading being most favorable during the early stages of establishment. FOR. SCI. 47(2):270–277.
Tropical Deforestation, Tenure Insecurity, and Unsustainability
Authors: Barbier Edward B. , Burgess Joanne C.
Published: April 2024

This article explores the effects of tenure insecurity on the migrant's decision to convert tropical frontier forestland to unsustainable agriculture. We develop and extend a Faustmann model to explore the effects of insecure property rights and unsustainability on the migrant's decision to convert tropical forestland to crop production, to maintain it for long-term timber production, or to mine the forest for timber and then abandon the land. We then provide a numerical simulation of the migrant's land-use decision based on data from the Amazon to compare the returns to mahogany plantation as opposed to agricultural conversion or timber mining. Increasing insecurity of land tenure leads to a decline in the value of timber relative to agricultural production land, thus creating an incentive for forest conversion. However, when land is easily degraded and tenure insecurity is high, timber mining and land abandonment may be a particular problem. Finally, we examine the role of private and government investment in establishing and maintaining secure land tenure. Once government “arrives” at the frontier, it can encourage sustainable timber production through providing secure harvesting rights and setting an optimal concession fee. FOR. SCI. 47(4):497–509.
Forest Land Conversion Over Time: Implications for the Faustmann Formula
Authors: Burgess J.C. , Ulph D.
Published: April 2024

The Faustmann timber production model has been used to examine the allocation of land between alternative forest land use options. This article provides a clarification and extension of this previous work. We use the basic forest land use options model to allow for the changes in forestland use over time. First, we modify Faustmann's original assumptions to allow for a one-off change in prices or an initial allocation constraint, and examine the forest land manager's decision to switch to an alternative land use at some point in the future. Second, we look at the case where prices evolve over time and it is optimal for the forest land manager to switch between land uses on an equilibrium path. This second extension provides a new application of the Faustmann timber production model. We discuss the theoretical insights and the implications for forest conversion. FOR. SCI. 47(4):510–519.
The Effect of Positional Errors on the Accuracy of Estimates in Guided Transect Sampling
Authors: Ringvall Anna , Ståhl Göran , Lämås Tomas
Published: April 2024

Guided transect sampling was recently proposed as a method for sampling sparse and geographically scattered populations if auxiliary data with high spatial resolution are available prior to the inventory. In practice, a surveyor will use GPS to follow predetermined survey lines. However, the surveyor will never be able to follow the lines exactly, and thus the accuracy of estimates is likely to be affected. The aim of this article was to study the loss in accuracy of estimates in guided transect sampling due to errors in navigation. The evaluation was made through Monte-Carlo simulations in different simulated forest types. The auxiliary data were considered to be volumes of deciduous trees, and the variable of interest the abundance of an indicator species connected to deciduous trees. To describe the surveyors' movements along the survey lines, a Brownian bridge process was proposed and evaluated with field data. The results from the study indicate that errors in navigation only have a minor effect on both bias and standard errors of estimates of the population total. The bias was not higher than 2.9%, and the increase in standard error not higher than 3.2 % in any forest type. FOR. SCI. 48(1):101–110.
The Ecology of Trees in the Tropical Rain Forest
Authors: Hendrick Ronald L.
Published: April 2024

The primary literature describing the ecology of tropical rain forest trees is vast, yet there are relatively few summaries of their ecological traits, especially from a comparative ecology perspective. Consequently, Turner's effort to do a comparative analysis of the ecology of species from throughout the tropical rain forest is a most welcome one. His primary goal to summarize the ecology of different tropical rainforest trees has resulted in a very well written summarization of their comparative ecology (and structure). He is less complimentary of the results of his effort to find “a new synthesis of the comparative ecology of tropical trees” (p. 247) after summarizing the relevant literature, but perhaps he has done more than he suspects.
Salamander Abundance in Regenerating Forest Stands on the Monongahela National Forest, West Virginia
Authors: Duguay Jeffrey P. , Wood Petra Bohall
Published: April 2024

We compared the abundance of salamanders in 18 hardwood stands treated with two-age management 15 yr after harvest, clearcutting 15 yr after harvest, and mature second-growth stands in the Monongahela National Forest of West Virginia during the summers of 1995 and 1996. Salamanders were captured with pitfall traps. We sampled 47,083 trap days and captured eight species of salamanders. Abundance of salamanders, expressed as number captured per 100 trap days, was higher (P = 0.06) in the mature second-growth than two-age treatment (two-age = 0.96 ± 0.11; clearcut = 1.46 ± 0.23; mature second-growth = 2.40 ± 0.57). Abundance of redback salamanders (Plethodon cinereus) also was higher (P = 0.09) in the mature second-growth than twoage treatment (two-age = 0.76 ± 0.14; clearcut = 1.48 ± 0.34; mature second-growth = 1.84 ± 0.51). These data indicate that 15 yr after harvest, harvested stands in the Monongahela National Forest may be less favorable than mature hardwood forests for some forest salamanders. FOR. SCI. 48(2):331–335.
Temporal Patterns in Aquatic and Avian Communities Following Selective Logging in the Upper Great Lakes Region
Authors: Flaspohler David J. , FisherHuckins Casey J , Bub Brian R. , van Dusen Peter J.
Published: April 2024

We surveyed populations of birds, fish, and aquatic macroinvertebrates in and along riparian systems within northern and mixed-hardwood forests that varied in time since last selection logging. Thirteen headwater stream sites from the Otter River watershed in Michigan's Upper Peninsula were included in the study. We detected a significant negative correlation between a standard index of habitat quality for coldwater streams (Great Lakes Environmental Assessment Section [GLEAS]) and time since last selective logging. Brook char (Salvelinus fontinalis Mitch.) abundance was also negatively correlated with year of forest cut as was the abundance of selected aquatic macroinvertebrate orders (Ephemeroptera, Plecoptera, and Trichoptera) that are sensitive to anthropogenic disturbance. Thus, relative to more recently logged stands, stands with older cuts had higher indices of habitat quality, more brook char, and the dominant aquatic macroinvertebrates tended to be those generally associated with higher quality coldwater streams. In contrast, bird species richness was positively related to year of last selective logging. As expected, basal area was lower and ground cover was greater in more recently logged stands. Thus, bird species richness was higher in stands with less basal area (recent cuts) than in stands with more basal area (older cuts). Percent ground cover showed a strong positive correlation with bird species richness. Twelve bird species were detected only in recently logged (since 1990) stands. The results of this multitaxa study suggest that selective logging of riparian forests is associated with changes in local animal abundance and diversity, and these effects appear to persist for approximately 30 yr postharvest. FOR. SCI. 48(2):339–349.
Use of a Landbird Monitoring Database To Explore Effects of Partial-Cut Timber Harvesting
Authors: Young Jock S. , Hutto Richard L.
Published: April 2024

We used data from the USDA Forest Service Northern Region Landbird Monitoring Program to investigate the effects of partial-cut timber harvesting on bird abundances in conifer forests within the northern Rocky Mountains. We present point-count data from four separate years of the longterm monitoring database, which included between 467 and 907 points, depending on the year. Five bird species were significantly more abundant in uncut forest stands in at least one year, and 17 species were more abundant in partially cut stands in at least one year. Four and eight species from these two groups, respectively, showed the same differences in a short-term, control/treatment comparison conducted in the same region, and no species showed contradictory treatment effects when the two studies were compared. Provided that vegetation data are coupled with bird abundance data, and provided that enough points are visited to compensate for an uncontrolled design, these results suggest that data from long-term monitoring points can be useful not only as sources of information about long-term population trends, but as sources of information about habitat relationships and the effects of land use. FOR. SCI. 48(2):373–378.
Effects of Landscape and Local Habitat Attributes on Northern Goshawk Site Occupancy in Western Washington
Authors: Finn Sean P. , Marzluff John M. , Varland Daniel E.
Published: April 2024

We quantified habitat structure, composition, and configuration at three spatial scales (39 ha nest area; 177 ha post-fledging area; 1,886 ha home range) and compared vegetative conditions with measures of northern goshawk (Accipiter gentilis) site occupancy at 30 historical nest sites (those containing at least one goshawk and a large stick nest when discovered) on Washington's Olympic Peninsula. Twelve of the 30 historical sites were occupied by one or more goshawks and 8 of the 12 contained a successful breeding pair. Sites that were occupied in 1 yr tended to remain occupied throughout the 3 yr study, and breeding success was strongly and positively correlated with occupancy. Occupied historical sites tended to have a high proportion of late-seral forest [>70% canopy closure of conifer species with >10% of the canopy trees >53 cm diameter at breast height (dbh)], reduced stand initiation cover, and reduced landscape heterogeneity at all three scales, but only the two larger scale models predicted occupancy successfully. Incorporating habitat attributes previously measured at finer (stand level) scales (canopy depth and percent shrub cover in the nest stand) improved our larger (landscape level) scale models of goshawk occupancy. Olympic Peninsula forest managers can promote goshawk occupancy, and therefore reproduction, by limiting the amount of early forest stand initiation cover (<20%) and landscape contrast in the home range and by maintaining potential nest stands (≥39 ha) having deep canopies and reduced shrub cover. FOR. SCI. 47(3):427–436.
How Joint is Joint Forest Production? An Econometric Analysis of Timber Supply Conditional on Endogenous Amenity Values
Authors: Pattanayak Subhrendu K. , Murray Brian C. , Abt Robert C.
Published: April 2024

In search of ways to enhance and sustain the flow of services from forests, policy makers in the public and private sectors look to forest sector models to project future forest uses. A major shortcoming of these models is a timber supply specification that inadequately accounts for suppliers choosing the structure of their forest capital to self-produce nontimber amenities. This inadequate characterization of resource use, if significant, can impede the development of sound forest policy, particularly in settings where forest owners possess diverse preferences for forest amenities. In this article, we develop and estimate a timber supply model that is consistent with the idea of joint self-production of timber and nontimber amenities, such that timber supply is a function of an endogenous distribution of forest inventory that correlates to ownership and management characteristics. Using data for the U.S. South and three-stage least squares procedures, we confirm that timber and nontimber amenities are jointly produced by private forest owners. We also note that owner and management characteristics influence joint production decisions. We believe that the parameters estimated through such an integrated empirical exercise could critically improve forest sector forecasting models and the related forest policy analyses. FOR. SCI. 48(3):479–491.
Competitive Capacity of Quercus rubra L. Planted in Arkansas' Boston Mountains
Authors: Spetich Martin A. , Dey Daniel C. , Johnson Paul S. , Graney David L.
Published: April 2024

Results of an 11 yr study of the growth and survival of planted northern red oak (Quercus rubra L.) seedlings (2-0 bare-root) are presented. More than 4,000 seedlings were planted under shelterwood overstories that were harvested 3 yr after planting. Results are expressed as planted-tree dominance probabilities. Dominance probability is the probability that a planted tree will live to attain a favorable competitive position (i.e., at least 80% of the mean height of dominant competitors) at a specified year. We interpret the resulting probability as a measure of the competitive capacity of an individual seedling, i.e., its potential of attaining dominance in a specified environment. Based on logistic regression analysis, dominance probabilities increase with time after shelterwood overstory removal for any given environment and initial seedling characteristics. At any specified time, dominance probabilities depend on initial seedling basal diameter before planting (stem caliper 2 cm above the root collar), site quality, intensity of weed control, and shelterwood percent stocking. Dominance probabilities increase with decreasing shelterwood stocking, increasing initial stem caliper, and increasing intensity of weed control. Other factors being equal, top clipped seedlings have higher dominance probabilities than unclipped seedlings. The reciprocals of the dominance probabilities provide silviculturally useful estimates of the numbers of trees that would need to be planted to obtain, on the average, one competitively successful tree. For example, if clipped seedlings averaging 6 mm in caliper were planted where oak site index was 24 m, shelterwood stocking was 80%, and the site was given no weed control before or after planting, obtaining one competitively successful tree 11 yr after planting (8 yr after shelterwood removal) would require planting 144 seedlings. Other factors remaining the same, increasing initial caliper to 22 mm would require planting only 5 trees to obtain 1 competitively successful tree. For the same size (22 mm) and type of seedling planted on site index 18 m under a shelterwood at 40 to 60% stocking and given two weed control treatments, only 1.4 trees would need to be planted. Results emphasize the sensitivity of competitive capacity, and thus the silvicultural potential, of planted northern red oaks in the Boston Mountains of Arkansas to the joint effects of field environment and initial seedling characteristics. FOR. SCI. 48(3):504–517.
A Site Dependent Simultaneous Growth Projection Model for Pinus kesiya Plantations in Zambia and Zimbabwe
Authors: Eerikäinen Kalle
Published: April 2024

The aim of this study was to create a stand level yield model for Pinus kesiya (Royle × Gordon) plantations in Zambia and Zimbabwe based on the simultaneous projection model approach. The purpose was to prepare prediction models for the measurable and allometrically related stand variables which characterize the development of planted P. kesiya stands. The modeled stand characteristics are assessable in the inventories of forest plantations and are frequently employed in traditional stand yield tables and modern growth simulators. Special attention was paid to the selection of flexible nonlinear model forms that are simple and stable. Two model forms were developed: (1) a polymorphic and base age invariant site index equation, used as a growth projection model for stand dominant height, and (2) a stand volume prediction model based on Honer's single tree volume model. The projection form of the site index equation was obtained using the algebraic difference approach to solve analytically the rate parameter of the autocatalytic growth model. The simultaneous growth projection model included a model for basal area median diameter. The basal area median diameter was also used as a predictor of stand basal area. This improved the accuracy of stand basal area predictions. A model for the basal area median diameter also makes it possible to apply theoretical diameter distributions for the prediction of future stand stages. FOR. SCI. 48(3):518–529.
Derivation, Fitting, and Implication of a Compatible Stem Taper-Volume-Weight System for Intensively Managed, Fast Growing Loblolly Pine
Authors: Zhang Yujia , Borders Bruce E. , Bailey Robert L.
Published: April 2024

Geometry-oriented methodology yielded a compatible taper-volume-weight system of models whose parameters were estimated using data from intensively managed loblolly pine (Pinus taeda L.) plantations in the lower coastal plain of Georgia. Two segments (separated at a stem ratio of 0.60 of total height) depicted taper, volume, and weight variations of the stems as well. The taper function defines stem taper as a proportion of the diameter at breast height. The segmented volume equation was derived from integration of the taper function along the stem, and it can be readily transformed into a ratio volume equation. Likewise, the segmented weight equation was obtained from integration of the volume function and a wood density function. Data analysis showed that fertilization has significantly reduced taper (inside and outside bark) on the upper segment and augmented stem merchantable volume in this segment. However, unit-weight (green wood and bark, green wood only, and dry wood only) was not significantly different between fertilized and unfertilized trees, implying that annual fertilization did not reduce the specific gravity very much. Finally, our analysis showed no significant impacts of complete vegetation control on taper, volume or weight characteristics. FOR. SCI. 48(3):595–607.
Harvest Scheduling with Area-Based Adjacency Constraints
Authors: McDill Marc E. , Rebain Stephanie A. , Braze Janis
Published: April 2024

Adjacency constraints in harvest scheduling models prevent the harvest of adjacent management units within a given time period. Two mixed integer linear programming (MILP) harvest scheduling formulations are presented that include adjacency constraints, yet allow the simultaneous harvest of groups of contiguous management units whose combined areas are less than some predefined limit. These models are termed Area Restriction Models, or ARMs, following Murray (1999). The first approach, the Path Algorithm, generates a set of constraints that prevent concurrent harvesting of groups of contiguous stands only when the combined area of a group exceeds the harvest area restriction. The second approach defines the set of Generalized Management Units (GMUs) that consist of groups of contiguous management units whose combined areas do not exceed the maximum harvest area limit. This formulation of the model can recognize direct cost savings—such as sale administration costs or harvest costs—or higher stumpage prices that may be realized by jointly managing stands. Example problems are formulated and solved using both ARM approaches and compared with models that restrict concurrent harvests on all adjacent units, regardless of area [termed Unit Restriction Models, or URMs, again following Murray (1999)]. The ARM formulations usually result in larger models and take longer to solve, but allow for higher objective function values than otherwise similar URM formulations. While the proposed ARM approaches should be applicable to more general problems, the examples are constructed so that the largest number of contiguous stands that can be harvested jointly is three. Strategies for reducing the size of the ARM formulations are discussed and tested. FOR. SCI. 48(4):631–642.
Bayesian Melding of a Forest Ecosystem Model with Correlated Inputs
Authors: Radtke Philip J. , Burk Thomas E. , Bolstad Paul V.
Published: April 2024

Bayesian melding, a method for assessing uncertainties in deterministic simulation models, was augmented to make use of prior knowledge about correlations between model inputs. The augmentation involved the use of a nonparametric correlation induction algorithm. The modified Bayesian melding technique was applied to the process-based forest ecosystem computer model PnET-II. The Bayesian posterior distribution for this analysis did not reflect prior knowledge of input correlations for five input pairs tested unless the correlations were explicitly accounted for in the Bayesian prior distribution. For other input pairs not known to be correlated prior to the analysis, numerous significant posterior correlations were identified. For one such pair of model inputs, a moderate posterior correlation was substantiated by empirical evidence that had not previously been taken into consideration. We conclude that, when possible, efforts should be made to account for prior knowledge of correlated inputs; however, Bayesian melding may elucidate input correlations in its posterior sample, even when no prior knowledge of such correlations exists. FOR. SCI. 48(4):701–711.
An Indirect Search Algorithm for Harvest-Scheduling Under Adjacency Constraints
Authors: Crowe Kevin , Nelson John
Published: April 2024

An indirect search heuristic is described for solving harvest-scheduling problems under adjacency constraints. This method works in combination with a greedy algorithm by diversifying the search through random changes in prioritized harvest queues. The indirect search is tested on a series of tactical problems and compared with published results for tabu search, simulated annealing, integer programming and linear programming. Results for large strategic problems are compared to a simulated annealing search algorithm. Objective function values are comparable to tabu search and simulated annealing, and solution times range from 38 seconds to 40 minutes, depending on the problem size and the number of iterations. Benefits of the indirect search method are: (1) objective function values can be higher than those computed through other heuristic algorithms, and (2) the algorithm produces good results without time-consuming experimentation with parameters of the search algorithm. The method also has potential for solving more complicated, multiple objective problems. FOR. SCI. 49(1):1–11.
Landscape Ecosystems of Northern Lower Michigan and the Occurrence and Management of the Kirtland's Warbler
Authors: Kashian Daniel M. , Barnes Burton V. , Walker Wayne S.
Published: April 2024

The Kirtland's warbler (Dendroica kirtlandii Baird) is an endangered songbird that nests in northern Lower Michigan in ecosystems dominated by young jack pine (Pinus banksiana Lamb.). An ecological, multifactor approach was used to determine the range and characteristics of landform-level ecosystems supporting the warbler and to compare the spatial and temporal patterns of warbler occupation among these ecosystems. Using an ecosystem rather than a strictly biological approach, the landforms occupied by the warbler are very diverse. Twelve landforms were identified based on 61 sites currently or formerly occupied by the warbler. Average annual jack pine height growth, an indicator of stand structural features that influences initial warbler colonization and duration of occupancy, differed significantly among landforms, resulting in marked differences in warbler occurrence in time and space across the breeding range. Landforms with favorable growing conditions for jack pine were colonized earliest and were occupied for the shortest duration, whereas landforms with unfavorable growing conditions were colonized relatively late but were occupied longest. Different ecological factors, such as the spatial position of landforms, microclimate, soil texture, or a combination of these factors, may account for favorable or unfavorable growing conditions for jack pine, which in turn affects the timing and duration of warbler occupancy. The classification and description of ecosystems occupied by the warbler provides an ecological framework for warbler management, especially when plantations rather than wildfire are the primary source of warbler habitat. FOR. SCI. 49(1):140–159.
Book Reviews: Burning Questions: A Social Science Research Plan for Federal Wildland Fire Management
Authors: Hesseln Hayley
Published: April 2024

Social science will play an important role in addressing wildfire issues in the 21st century as fire risk continues to escalate and society moves farther into forests and wildlands at the periphery of urbanization. A better understanding of the social relationships encompassing fire management will be useful for policymakers, fire personnel, and the public. Furthermore, the use of social science will be beneficial in elucidating the complex relationships among these groups.
Guided Transect Sampling with a New Strategy for Second-Stage Guidance
Authors: Ringvall Anna
Published: April 2024

Guided transect sampling (GTS) was recently proposed as a method for surveying sparse and geographically scattered populations if prior information with high spatial resolution is available. With this method, wide survey strips are, during a first stage, randomly selected in the area to be surveyed. In the second stage, the selected first-stage strips are subsampled with a survey line or survey strip based on the prior information. In this article, a new strategy for second-stage guidance is developed and evaluated in a simulation study. The suggested strategy uses an assumed model for the relationship between the prior information and the variable of interest to find an efficient design for selecting the second-stage transects. The performance of the suggested strategy is evaluated in terms of the variance obtained in different realizations of the assumed model. Results from the simulation study indicate that the suggested strategy is an efficient alternative to previously suggested strategies, if the correspondence between the model population and the real population is good. On the other hand, if the difference between the two populations is large, large variances were sometimes obtained. FOR. SCI. 49(2):169–175.
Photosynthesis and Growth in Seedlings of Five Forest Tree Species with Contrasting Leaf Anatomy Subjected to Supplemental UV-B Radiation
Authors: Bassman John H. , Edwards Gerald E. , Robberecht Ronald
Published: April 2024

Seeds or cuttings of five forest tree species with contrasting leaf anatomies and shoot growth characteristics were cultivated under three different UV-B radiation regimes: ambient (7.5 kJ m-2 d-1 = 1×), two times ambient (2×), or three times ambient (3×) biologically effective UV-B radiation (UV-BBE) USA at the summer solstice, as calculated for Pullman, Washington. Experiments were conducted in glasshouses using a nonmodulated UV-B lamp system. Gas exchange was measured in recently mature leaves after six months of exposure. Photosynthetic rates were reduced by 2× and 3× treatments in Populus trichocarpa, and by the 3× regime for Pseudotsuga menziesii. Photosynthetic rates increased under the 2× treatment for Pseudotsuga menziesii and under the 3× treatment for Picea engelmannii. For Pinus ponderosa and Quercus rubra, photosynthetic rates were unchanged. Dark respiration increased under both 2× and 3× treatments for Picea engelmannii and by the 3× level in Quercus rubra, but was unaffected in the other species. Transpiration and stomatal conductance generally mirrored changes in photosynthesis. Water use efficiency increased for Pinus ponderosa (2× treatment) and Quercus rubra (2× and 3×), was reduced for Populus trichocarpa (2× & 3×), and remained unchanged in the other species. Enhanced UV-B radiation changed the shape of light response curves for all species. Quantum yields were unchanged for Pinus ponderosa, increased for Pseudotsuga menziesii (2×) and Picea engelmannii (2× and 3×) and were reduced in Populus trichocarpa (2×) and Quercus rubra (3×). Light compensation points were higher in the conifers (3×) and reduced in the angiosperms (2×). Chlorophylls were generally reduced by higher UV-B radiation in the conifers and for Populus trichocarpa (3×), but increased for Quercus rubra. Ultraviolet-absorbing compounds increased in the conifers and were unchanged in the angiosperms by enhanced UV-B radiation. Height growth increased (Pinus ponderosa, 3×; Quercus rubra, 2×), decreased (Picea engelmannii, 3×) or was unchanged (Pseudotsuga menziesii, Populus trichocarpa) by higher levels of UV-B radiation. Stem diameter and plant biomass were generally reduced, and shoot: root ratios increased for all species except Populus trichocarpa. Our results do not appear to support the hypothesis that inherent leaf anatomy or shoot growth pattern in these species directly determine the response of photosynthesis and growth to enhanced UV-B radiation. FOR SCI. 49(2):176–187.
Biomass Partitioning and Growth Efficiency of Intensively Managed Pinus taeda and Pinus elliottii Stands of Different Planting Densities
Authors: Colter Burkes E. , Will Rodney E. , Barron-Gafford Greg A. , Teskey Robert O. , Shiver Barry
Published: April 2024

The effect of planting density (740, 2,220, 3,700, and 4,440 trees/ha-1) on growth efficiency and biomass partitioning was examined in intensively managed stands of 4-yr-old loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) stands on the Coastal Plain of southern Georgia. The primary objective of this study was to determine whether decreased partitioning of biomass to stem relative to other tree components limits stem biomass growth on a per hectare basis as stand density increases. Fourth growing season stem biomass production did not increase proportionally with planting density, indicating that stem biomass growth was limited at the higher stand densities. For both species, growth efficiency (stem biomass growth produced during the fourth growing season per unit of leaf biomass) was significantly lower for stands planted at 740 trees/ha-1 compared to the other stand densities. Similarly, the ratio of stem biomass growth: fine root biomass was significantly lower for the 740 trees/ha-1 stand. Within sites, planting density had no effect on the ratio of fine root biomass: leaf biomass for either species. Overall, these results indicate that partitioning to stem growth increased relative to foliage or fine roots as stand density increased. Therefore, the limitation in stem biomass growth on a per hectare basis that occurred as stand density increased was not due to changes in partitioning, but probably due to a limitation in net primary production. FOR. SCI. 47(2):224–234.
Valuing Biodiversity, Aesthetics, and Job Losses Associated with Ecosystem Management Using Stated Preferences
Authors: Xu Weihuan , Lippke Bruce R. , Perez-Garcia John
Published: April 2024

The study performs a joint estimation of the values for three important attributes of forest ecosystem management—biodiversity, aesthetics, and rural employment impacts using a choice-based, stated preference approach. It develops the marginal willingness-to-pay schedule for the three attributes for timber rural, other rural, and urban communities in Washington State. In contrast to the conventional wisdom in neoclassical economics, the public perceives job losses as losses of social welfare in this study. There are differences as well as similarities among the preferences of the three communities for the attributes of ecosystem management. The results show that the overall preferences of the timber rural and urban communities towards ecosystem management are substantially different, while the preferences of other rural community are not statistically significantly different from the other two communities. The estimated environmental and social values make it possible for policy makers and resource managers to compare and assess the trade-offs of different management plans. For example, with the biodiversity index level at 60, where an index of 50 relates current conditions, and rural forest-related job losses at 5,000, each household in urban communities in Washington State is willing to pay $31.44 annually for an additional unit of improvement of biodiversity, and $45.97 annually for avoiding an additional 1,000 rural job losses. The trade-off relationship for the given biodiversity and job loss levels suggests each household in urban communities each year is willing to trade 684 additional rural forest-related job losses with one unit of biodiversity improvement, ceteris paribus. Similar trade-off relationships for households in timber and other rural communities suggest each is willing to trade 598 and 388 additional rural forest-related job losses, respectively, with one unit of biodiversity improvement, ceteris paribus. The trade-off between aesthetics and job losses are 1,229, 452, and 686 additional jobs with one unit of aesthetics improvement for urban, timber, and other rural households, respectively. The trade-off relationships provide important information for improving the efficiency and equity of forest ecosystem management. FOR. SCI. 49(2):247–257.
A Comparison of Compatible and Annual Growth Models
Authors: Ochi Norihisa , Cao Quang V.
Published: April 2024

Compatible growth and yield models are desirable because they provide the same growth estimates regardless of length of growth periods. However, the compatibility constraints restrict the number of possible models. This restriction might be overcome by using models that predict annual stand growth based on periodic measurements. The advantages of this approach are (1) the flexibility allowed in building annual growth models without constraints, and (2) the step-invariance property maintained by these models. An annual growth model was developed in this study that predicts yield based on information from the previous year. For 162 plots from the Southwide Seed Source Study of loblolly pine (Pinus taeda L.), the annual growth model provided better predictions of stand survival, basal area, and volume than two compatible growth models. FOR. SCI. 49(2):285–290.
Clustering Versus Regression Trees for Determining Ecological Land Units in the Southern California Mountains and Foothills
Authors: Franklin Janet
Published: April 2024

A landscape stratification was required for simulation modeling of fire disturbance and succession in the mountains and foothills region of the Peninsular Ranges within San Diego County, California. Two quantitative approaches to mapping ecological land units (ELUs) were compared for a 3,878 km2 study area. These were: (a) clustering of climate overlain with key terrain variables; and (b) regression tree modeling of climate, geology, and terrain variables using a normalized difference vegetation index (NDVI), derived from a Landsat Thematic Mapper image, as the dependent variable. Terrain variables derived from a digital elevation model included slope gradient, cosine transformed slope aspect, potential solar insolation, and a topographic moisture index. For the simulation model ELUs were required that would stratify the landscape according to biomass (fuel) accumulation dynamics, related to site productivity, and probabilities of plant species establishment. Therefore, ELUs were defined using abiotic variables, and the resulting stratifications were evaluated by their ability to reduce within-class variance in the NDVI (as an index of biological productivity), and by comparing them to a map of existing vegetation. While the regression tree method resulted in classes that explained more variance in NDVI than classes resulting from unsupervised clustering, the difference was not large. In contrast, the unsupervised approach resulted in ecological land classes that were more strongly related to existing vegetation patterns. FOR. SCI. 49 (3):354–368.
Classification Accuracy for Stratification with Remotely Sensed Data
Authors: Czaplewski Raymond L. , Patterson Paul L.
Published: April 2024

Tools are developed that help specify the classification accuracy required from remotely sensed data. These tools are applied during the planning stage of a sample survey that will use poststratification, prestratification with proportional allocation, or double sampling for stratification. Accuracy standards are developed in terms of an “error matrix,” which is familiar to remote sensing specialists. In addition, guidance is provided to determine when new remotely sensed classifications are needed to maintain acceptable levels of statistical precision with stratification. FOR. SCI. 49(3):402–408.
Combining Remotely Sensed Optical and Radar Data in kNN-Estimation of Forest Variables
Authors: Holmström H. , Fransson J.E.S.
Published: April 2024

The use of optical and radar data for estimation of forest variables has been investigated and evaluated by employing the k nearest neighbor (kNN) method. The investigation was performed at a test site located in the south of Sweden consisting mainly of Norway spruce and Scots pine forests with standwise stem volume in the range of 0–430 m3 ha-1. The kNN method imputes weighted reference plot variables to areas to be estimated (target areas), facilitating further use of data in forestry planning models. Remotely sensed multispectral optical data from the SPOT-4 XS satellite and radar data from the airborne CARABAS-II VHF SAR sensor were used, separately and combined, to define weights in the kNN algorithm. The weights were inversely proportional to the image feature distance between the reference plot and the target area. The distance metric was defined using regression models based on the image data sources. Positive impact on the accuracies of stem volume and age estimates was found by combining the two image data sources. Stem volume, at stand level, was estimated with a RMSE of 37 m3 ha-1 (22% of the true mean value) using the combination of optical and radar data, compared to 50 m3 ha-1 (30%) for the best single-sensor case in this study. In conclusion, the results indicate that the accuracy of forest variable estimations was substantially improved by using multisensor data. FOR. SCI. 49(3):409–418.
Combining High-Resolution Aerial Photography with Gradient-Directed Transects to Guide Field Sampling and Forest Mapping in Mountainous Terrain
Authors: Sandmann Holger , Lertzman Ken P.
Published: April 2024

Forest inventory and management relies on accurate maps of vegetation structure and composition. Creating such maps typically proceeds in two main stages: delineating stand boundaries on midscale aerial photography (≈1:15,000) followed by collection of reference data in field plots. Technical and logistical limitations arise with respect to the resolution of photography, the allocation of field plots, and the sequence of the stages. Here we present a novel approach for forest mapping that (1) places the mapping process as the last rather than the first stage; (2) concentrates sampling in areas with strong environmental gradients; and (3) uses large-scale, high-resolution aerial photography (≈1:2,000) to supplement field data and midscale airphotos. Our design builds on observations that plant communities in mountainous areas often exhibit strong correlations with environmental variables and that digital or hardcopy maps of these variables are becoming more widely available. In the first stage, 1:2,000 aerial photography is obtained via helicopter-mounted small-format cameras along flight lines that are located subjectively to follow significant environmental gradients. In the second stage, field plots are placed within airphoto transects to provide reference data of forest conditions. An integrated analysis of plot data and high-resolution photography provides the empirical basis for the development and calibration of an interpretation key. In the third stage, this key is applied to the delineation and classification of forested area on stereoscopic 1:15,000 aerial photography across the landscape of interest. We demonstrate this approach using a watershed in southwestern British Columbia and compare four probability-sampling designs with the gradient-directed approach proposed here using computer simulations. The results indicate that sampling along topographic gradients leads to a loss of accuracy with respect to estimation of distributional parameters. However, gradient-directed sampling is as likely as probability sampling to capture the full range of variability in forest conditions, with greatly improved logistics and cost-effectiveness. We conclude that our sampling design is a practical alternative for mapping projects in topographically complex landscapes. FOR. SCI. 49(3):429–443.