bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Thinning Effects on Ring Specific Gravity of Loblolly Pine (Pinus taeda L.)
Authors: Tasissa Gudaye , Burkhart Harold E.
Published: April 2024

Effects of thinning on ring specific gravity in loblolly pine trees were examined in a regional trial in the southeastern United States. The thinning study consisted of two treatment levels (30% and 50% of the basal area removed) and a control. Thinning did not alter the proportion of the annual ring in earlywood or latewood and thus did not affect ring specific gravity. There was regional variation in average ring specific gravity, with trees from the Coastal Plain having higher ring specific gravity than trees from the Piedmont or the Highlands. Within the Coastal Plain, trees in the Gulf Coastal Plain tended to have higher average ring specific gravity than trees in the Atlantic Coastal Plain. A ring specific gravity prediction model was developed based on ring position, tree, stand, and site attributes. Much of the variation in ring specific gravity was due to within-tree variation; consequently, stand and site factors accounted for a limited proportion of variation in ring specific gravity. As the within-tree observations used in the study tended to be correlated, a direct covariance modeling approach was used to account for the correlation among observations. For. Sci. 44(2):212-223.
Qualitative Comparative Analysis: A Useful Tool for Research into Forest Policy and Forestry Conflicts
Authors: Hellström Eeva
Published: April 2024

The internationalization of the forestry debate and forest policy brings about a growing need to develop, apply, and discuss comparative methodologies in forestry research. This paper illustrates and discusses the use of Qualitative Comparative Analysis (QCA), a new comparative tool in forest policy research. The advantages and disadvantages of the method are demonstrated by reanalyzing previous research on public environmental criticism of forestry in Finland, Sweden, Norway, West Germany, France, and the United States between 1950 and 1983. In particular, the reanalysis illustrates the potential benefits of systematic techniques of comparison as supplementary tools to traditional "common sense" interpretations of qualitative data. In addition to arguing on behalf of the technical applicability of the method to comparative forest policy research, a need is expressed to expand the use of the method from causal to noncausal applications. For. Sci. 44(2):254-265.
Forest Harvests and Wood Products: Sources and Sinks of Atmospheric Carbon Dioxide
Authors: Winjum Jack K. , Brown Sandra , Schlamadinger Bernhard
Published: April 2024

Changes in the net carbon (C) sink-source balance related to a country's forest harvesting and use of wood products is an important component in making country-level inventories of greenhouse gas emissions, a current activity within many signatory nations to the UN Framework Convention on Climate Change. We propose two approaches for estimating national C inventories from forest harvesting and wood product utilization (excluding forest regrowth): the atmospheric-flow method and the stock-change method. The former has the atmosphere as its system of interest and counts all flows to and from the atmosphere for a particular country. The latter looks at a country's forest and wood product C stocks and how they change over time. Here we develop these two methods, and estimate national C source-sink balance from the readily available FAO global forest products database for countries, regions, and the world. Both methods gave a worldwide estimated source of 980 Tg of C in 1990 as a result of forest harvests and wood product utilization; about 60% came from developing countries and 40% from developed countries. Estimates (Tg C) for selected developing countries for the atmospheric-flow/stock-change method were: Brazil, 72/73; India, 81/80; Indonesia, 53/56; and Ivory Coast, 3.9/4.3; and for selected developed countries (again atmospheric-flow/stock-change method): Canada, 36/50; Finland, 8.8/13; New Zealand, 2.7/3.4; and United States 141/138. Net wood exporters show lower numbers in the atmospheric-flow method, net wood importers in the stock-change method. Among the variables that most consistently and strongly affected C emissions for a given country in 1990 were: roundwood production, slash left to oxidize, and commodity wood put into uses ≥ 5 yr. We conclude with a discussion that shows how choosing either one of the two methods for wood harvest accounting has potential policy implications or impacts on the incentives or disincentives to use wood. For. Sci. 44(2):272-284.
Measuring the Efficiency of Public Forestry Organizations
Authors: Viitala Esa-Jussi , Hänninen Harri
Published: April 2024

The decreasing budgets of public forestry organizations have given rise to the present need to evaluate their efficiency and to find means to improve it. In this paper the efficiency of 19 state-funded, regional Forestry Boards is investigated using Data Envelopment Analysis (DEA). In addition, the prime determinants of efficiency are examined using Tobit models. The results indicate a substantial variation in efficiency across Forestry Boards with a potential for input saving in the range of 20%. It seems that, of the controllable factors, management style and support are associated with efficiency. It appears also that applying DEA with Tobit models provides a useful two-stage approach to assess and explain efficiency differences among public forestry organizations. For. Sci. 44(2):298-307.
Influence of Intensive Culture on Leaf Net Photosynthesis and Growth of Sweetgum and Loblolly Pine Seedlings
Authors: Samuelson L. J.
Published: April 2024

The influence of (1) complete weed control only, (2) weed control and irrigation, (3) weed control and irrigation with a fertilizer solution (fertigation), and (4) weed control and fertigation plus pest suppression (pine only) on midday light-saturated leaf net photosynthesis (Pn) of sweetgum (Liquidambar styraciflua L.) and loblolly pine (Pinus taeda L.) was examined monthly, two growing seasons after plantation establishment. Irrigation but not fertigation increased Pn on all dates and more than doubled height and diameter of sweetgum after the first growing season. Greater Pn in sweetgum in response to irrigation was, in part, a result of reductions in stomatal limitation to Pn and decreased stomatal sensitivity to vapor pressure deficit. In loblolly pine, Pn was increased only by irrigation and only on one date during the first growing season. No effect of treatment on Pn of either species was observed for the second season. After two growing seasons, an eight-fold increase in aboveground biomass and six-fold increase in leaf area were observed in sweetgum in response to fertigation relative to the control treatment. Fertigation plus pest control treatment eliminated tip moth damage to shoots of loblolly pine during the first growing season and resulted in a doubling of total biomass and tripling of leaf area. Maximum biomass accumulation in sweetgum and loblolly pine after two seasons of intensive culture was mainly a function of leaf area rather than Pn For. Sci. 44(2):308-316.
Segmenting the Market for Environmentally Certified Wood Products
Authors: Ozanne Lucie K. , Smith Paul M.
Published: April 2024

A study was conducted to segment consumers in terms of their attitudes toward environmentally certified wood products. Factor analysis reduced seven variables of environmental certification to two distinct factors. Cluster analysis, performed on the seven variables of forest and wood products certification, suggested the existence of six relatively homogeneous groupings or segments of consumers. Multiple discriminant analysis provided a method for profiling these six consumer segments in terms of demographic, attitudinal, and trust (respondent's trust in potential certifying organizations) variables. This paper identifies one consumer segment of approximately 25 million Americans who would most likely seek out environmentally certified wood products. Relative to our other study respondents, they can be described as politically liberal, Democrats, female, members of an environmental organization, fairly well educated, concerned about the quality of the environment and forest resources, and having high self-rated environmental knowledge. In addition, these respondents would place the most trust in the certification claims made by an environmental organization. Conversely, a consumer segment of nearly 10 million Americans appears highly skeptical of certification programs, in general. Consistent with previous literature, our demographic variables were less effective in discriminating among groupings of consumers than attitudinal and trust variables. Implications of segmentation strategies are discussed for both industrial managers and forest policymakers. For. Sci. 44(3):379-389.
Impact of Alternative Regeneration Methods on Genetic Diversity in Coastal Douglas-Fir
Authors: Adams W. Thomas , Zuo Jinghua , Shimizu Jarbas Y. , Tappeiner John C.
Published: April 2024

Genetic implications of natural and artificial regeneration following three regeneration methods (group selection, shelterwood, and clearcut) were investigated in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) using genetic markers (17 allozyme loci). In general, harvesting followed by either natural or artificial regeneration resulted in offspring populations little altered from those in the previous generation. Cutting the smallest trees to form shelterwoods, however, resulted in the removal of rare, presumably deleterious, alleles, such that slightly fewer alleles per locus were observed among residual trees (2.76) and natural regeneration (2.75) than found in uncut (control) stands (2.86). Thus, although the shelterwood regime appears quite compatible with gene conservation, it would be best to leave parent trees of a range of sizes in shelterwoods designated as gene conservation reserves, in order to maximize the number of alleles (regardless of current adaptive value) in naturally regenerated offspring. Seedling stocks used for artificial regeneration in clearcut, shelterwood, and group selection stands (7 total) had significantly greater levels of genetic diversity, on average, than found in natural regeneration. This is probably because the seeds used in artificial seedling stocks came from many wild stands and thus, sampled more diversity than found in single populations. For. Sci. 44(3): 390-396.
Analyzing Public Inputs to Multiple Objective Decisions on National Forests Using Conjoint Analysis
Authors: Dennis Donald F.
Published: April 2024

Faced with multiple objectives, national forest managers and planners need a means to solicit and analyze public preferences and values. A conjoint ranking survey was designed to solicit public preferences for various levels of timber harvesting, wildlife habitats, hiking trails, snowmobile use, and off-road-vehicle (ORV) access on the Green Mountain National Forest. The survey was completed by 76 respondents during public involvement meetings. An ordered probit model was used to estimate linear and quadratic main effects. Respondents preferred moderate levels of timber harvesting and snowmobile access and lower levels of ORV access. They favored a mixture of mature closed canopy and younger more open forests over either extreme and were somewhat indifferent toward extending the network of hiking trails. For. Sci. 44(3):421-428.
The Effects of Fixed-Area Plot Width on Forest Canopy Height Simulation
Authors: Nelson Ross F. , Gregoire Timothy G. , Oderwald Richard G.
Published: April 2024

Mapped-stand data which includes tree location and mensuration data may be used to simulate the height characteristics of a forest canopy in a computer. The dimensions of the rectangular, fixed-area ground plot which is used to collect the tree location and mensuration data can profoundly affect the accuracy of the resultant computer reconstruction of forest canopy heights. Thin fixed-area plots result in forest canopy height constructs (i.e., canopy height models, or CHMs) which are shorter and less dense than the actual forest stand. Ninety-nine 0.405 ha forest stands in the southeastern and south central United States were analyzed. For each stand, a top-of-canopy height model was generated for the entire stand on a 0.25 m x 0.25 m grid. The mean canopy height and the canopy density of the simulated stand was calculated. A Monte Carlo simulator established randomly located sample plots of varying plot width (1 m to 20 m) at three different sampling intensities (1%, 5%, and 10% of stand area) in the mapped stand. The trees selected on any particular plot were used to generate a CHM, and the sample mean canopy height and canopy density were compared with the corresponding stand values. Samples collected using 1 m wide plots resulted in height models which underestimated average canopy height and canopy closure with deviations greater than 5% of the stand value, 95-100% of the time. The underestimation results from the construction of top-of-canopy architecture based on measurements of crowns belonging only to trees whose boles are within the plot. This construction technique omits crowns extending over the plot belonging to tree boles located off the plot. Thinner plots tend to miss more of the trees which support the canopy over the plot. For the 99 stands considered in this study, ground plot widths on the order of 6 to 8 m were required in order to acquire ground data which could be used to accurately model forest canopy height characteristics. The minimum ground plot width required to produce an accurate height model decreased with increasing stem density; a plot width of 4 m, for instance, may be used at stem densities of ~2000 stems ha-1. For. Sci. 44(3):438-444.
Allometry and Growth
Authors: Broad L. R.
Published: April 2024

A theory of multivariate allometry is developed. Bivariate and multivariate allometry are then shown to be compatible, the defining differential equations being analogs of each other and invariant under analogous allometric transforms. The relevance of allometric equations to growth modeling is examined. Commonly used growth models that are invariant under allometric transforms are capable of being formulated in terms of allometric (growth) differential equations. Methods for formulating and solving multivariate growth models are demonstrated. For. Sci. 44(3):458-464.
Regional Cost Function Analysis of the Logging Industry in the Pacific Northwest and Southeast
Authors: Smith Phillip , Munn Ian A.
Published: April 2024

Nonhomothetic translog cost functions with two variable inputs, labor and capital, were estimated to compare the underlying production structure of the logging industry in the Pacific Northwest and Southeast regions of the United States from 1963 to 1992. The parent cost function and capital share equation for each region were estimated using Maximum Likelihood Estimation techniques. Both equations were significantly different between regions. The industry in both regions was capital-using over the study period. Labor and capital were substitutes in each region, but substitution possibilities were limited. Input substitution was more elastic in the Southeast, and therefore the industry in the Southeast would be better able to adjust to changes in input prices or output demand. Additional tests determined that homothetic, homogeneous, and time invariant functions would be inappropriate for the logging industry in either region. For. Sci. 44(4):517-525.
Tree-Ring Responses to Drought Across Species and Contrasting Sites in the Ridge and Valley of Central Pennsylvania
Authors: Abrams Marc D. , Ruffner Charles M. , Morgan Todd A.
Published: April 2024

Annual tree-ring variation between 1984 and 1995 was measured in ten hardwood species in central Pennsylvania (USA) to assess differential drought impacts on xeric ridge, dry-mesic barrens, mesic valley, and wet-mesic riparian sites. Each tree species occurred on two or more sites. Four droughts of moderate to severe intensity occurred during the study period. In general, trees on the xeric ridge and wet-mesic riparian sites were more frequently impacted with reductions in the ring width index, whereas trees on the mesic valley and dry-mesic barrens sites had fewer growth reductions. Annual variation in growth was negatively correlated with summer temperature, particularly for species on the riparian site. Six of twenty-three species-by-site combinations had above average growth during one or more of the droughts, while 8 of 23 species-by-site combinations had below average growth the year following drought. The species with the largest decrease in the ring width index during drought varied among the sites, and included Acer rubrum in the valley, Prunus serotina in the barrens and riparian sites, and Quercus rubra and Acer rubrum on the ridge. Comparing tree-ring data from this study with leaf gas exchange data from other studies resulted in several inconsistencies in drought responses; therefore, information from both approaches may be needed in accurately assessing species drought tolerance rating. For. Sci. 44(4):550-558.
Genetic Parameters and Breeding Value Predictions for Eucalyptus Nitens Wood Fiber Production Traits
Authors: Tibbits Wayne , Hodge Gary
Published: April 2024

A base breeding population of 13,000 trees from about 300 Eucalyptus nitens families of open-pollinated origin in 6 provenances of native forest stands, was established in 8 tests, analyzed for genetic parameters and used for breeding value and gain prediction. Traits considered were basal area (BA), basic density (BD), and kraft pulp yield (PY) in 4- to 8-yr-old trees. Measurement of PY, whether taken as individual trees (PYI) or composites (PYC), were considered as the same trait, since the average Type B genetic correlation (rBg) between PYI and PYC was 0.94. Trees with the "early-adult form" typically from the Errinundra provenance appeared to have the poorest PY, averaging 1 to 3% points lower than all the other provenances. This provenance was excluded from detailed genetic analyses. Significant differences among the other five provenances were found for all traits. Four provenances were reasonably similar, but northern New South Wales was estimated to be lowest for BA and PY, and highest for BD. Single-site biased heritabilities (h2b) varied substantially from site to site, and averaged 0.32 ± 0.05 for BA, 0.43 ± 0.09 for BD, 0.37 ± 0.08 for PY. Heritability estimates from combined-site analyses were 0.19 for BA, 0.42 for BD, and 0.37 for PY. Genotype x environment (g x e) interaction was estimated using rBg. For BD and PY, rBg was 0.94, indicating no major g x e. Moderate g x e interactions were detected for SA, with rBg at 0.60. Genetic correlation between BA and PY, and between BD and PY were favorable, but between BA and BD was unfavorable (genetic correlation = 0.24, 0.41 and -0.24 respectively). For. Sci. 44(4):587-598.
Within-Stem Variation in Tropolone Content and Decay Resistance of Second-Growth Western Redcedar
Authors: DeBell Jeffrey D. , Morrell Jeffrey J. , Gartner Barbara L.
Published: April 2024

Western redcedar (Thuja plicata Donn) is a commercial species valued for its high decay resistance, which is due to the presence of toxic extractives (tropolones) in the heartwood. We measured tropolone content and weight loss in soil block tests using samples taken from 11 second-growth western redcedar trees. Tropolone content increased with rings from the pith, and in the outer heartwood, increased from the top to the base of the tree. We did not find any consistent increase or decrease in tropolone content with height in the tree for samples the same number of rings from the pith. Our data suggest that the lower tropolone content near the pith is largely a juvenile effect, associated with wood formed near the active crown. This has implications for choosing a rotation length if wood of uniformly high decay resistance is desired, because younger trees contain a greater proportion of wood close to the pith. However, we also found large tree-to-tree differences in the rate of tropolone increase with age from the pith. This may have promise for maintaining uniformly high decay resistance if the factors underlying the tree-to-tree differences can be discovered and managed. Our results from soil block tests for decay resistance were more variable, but in general, wood near the pith, which was low in tropolones throughout the tree, was extremely variable in decay resistance; outer heartwood with high tropolone content showed higher, less variable decay resistance, while outer heartwood with low tropolone content remained variable in decay resistance. For. Sci. 45(1):101-107.
Three-Year Survival and Growth of Douglas-Fir Seedlings Under Various Vegetation-Free Regimes
Authors: Rose R. , Ketchum J.S. , Hanson D. E.
Published: April 2024

Responses of Douglas-fir seedlings were studied for 3 yr following eight vegetation-control treatments in three western Oregon clearcuts. The objectives were to determine seedling growth response to different areas of spot vegetation control and to determine the relative influence of early woody and herbaceous competition on seedling growth. Herbicide treatment areas varied in size from those receiving no control to full control (9.3 m2). Controlled areas were maintained free of herbaceous vegetation for 2 yr and all woody vegetation was controlled for 3 yr. Two additional treatments, complete control of woody vegetation only and complete control of herbaceous vegetation only, were also examined. On two sites (Summit and Marcola), seedling growth parameters were maximized at or near full vegetation control with a tree spacing of 3 m x 3 m. On the third site (Pedee), maximum growth response occurred between 5 and 6 m2; of control. Herbaceous vegetation control resulted in increased seedling growth at all sites while woody vegetation control yielded increased seedling growth only at the Pedee site. Cumulative 3 yr herbaceous cover accounted for 68% and 41% of the variability in stem volume at Summit and Marcola, respectively. Adding cumulative 3 yr woody cover to the model accounted for an additional 18% and 49% of the variability in stem volume at Summit and Marcola, respectively. At Pedee, neither herbaceous nor woody cover significantly influenced 3 yr stem volume, suggesting that factors other than vegetation cover were responsible for differences measured. For. Sci. 45(1):117-126.
Mexican Spotted Owl Home Range and Habitat Use in Pine-Oak Forest: Implications for Forest Management
Authors: Ganey Joseph L. , Block William M. , Jenness Jeffrey S. , Wilson Randolph A.
Published: April 2024

To better understand the habitat relationships of the Mexican spotted owl (Strix occidentalis lucida), and how such relationships might influence forest management, we studied home-range and habitat use of radio-marked owls in ponderosa pine (Pinus ponderosa)-Gambel oak (Quercus gambelii) forest. Annual home-range size (95% adaptive-kernel estimate) averaged 895 ha ± + 70 (SE) for 12 individuals and 997 ha ± 186 (SE) for 7 pairs of owls. On average, the 75% adaptive-kernel contour (a probability contour containing 75% of the owl locations) included 32 and 30% of the annual home range for individuals and pairs, respectively, suggesting high concentration of activity in a relatively small portion of the home range. Relative area of three cover types (ponderosa pine forest, pine-oak forest, and meadow) did not differ between seasonal ranges, and owls used these cover types in proportion to their relative area during both breeding and nonbreeding seasons. In contrast, relative area of four canopy-cover classes varied between seasons. Breeding-season ranges contained greater proportions of areas with canopy cover ≥ 60% and lower proportions of areas with 20-39% canopy cover than nonbreeding-season ranges. Owls roosted and foraged in stands with ≥ 60% canopy cover more than expected during both breeding and nonbreeding seasons, and used stands with 20-39% canopy cover less than expected except for foraging during the breeding season. Stands used for foraging did not differ in structure between seasons and had greater canopy cover and less rock cover than stands with no documented use. Stands used for roosting differed between seasons in a multivariate comparison, but no individual habitat variables differed between seasons in subsequent univariate comparisons. In both seasons, stands used for roosting had greater canopy cover than stands with no roosting use. Closed-canopy forests, which were used heavily by owls, were relatively rare on the study area, suggesting that such forests warrant special protection in areas managed for spotted owls. This may conflict with efforts to restore more open conditions in ponderosa pine forests. For. Sci. 45(1):127-135.
Simulation of Thinning with a Single-Grip Harvester
Authors: Eliasson Lars
Published: April 2024

A simulation model of a single-grip harvester was constructed to evaluate different silvicultural treatments and to compare different machine concepts with a minimum of confounding factors. The model simulates machine movement, boom movement, felling, delimbing, and cross-cutting in stands where both size and position of each tree are known. To validate the model, model output was compared with data from recent time studies. Effects on harvester productivity of three harvesting intensities (extraction of 30, 40, and 50% of the basal area when thinning from below) and four distances between machine positions were studied. Productivity increased with harvesting intensity and with distance between machine positions. For. Sci. 45(1):26-34.
Stakeholder Perspectives on Appropriate Forest Management in the Pacific Northwest
Authors: Kearney Anne R. , Bradley Gordon , Kaplan Rachel , Kaplan Stephen
Published: April 2024

One potential source of the controversy over forest management in the Pacific Northwest is differences in stakeholders' conceptualizations, or perspectives, on appropriate forest management. This study explores the nature of stakeholders' perspectives and identifies some of the differences and commonalities among them. Study participants included 23 individuals from 3 forest stakeholder groups: the USDA Forest Service, timber industry, and environmentalists. Participants' perspectives on appropriate forest management were assessed using a conceptual content cognitive map (3CM) task. Results indicate the existence of a wide range of concerns including issues related to the focus, setting, and process of management. The pattern of differences and similarities among stakeholder groups with respect to these concerns was found to be complex and to deviate substantially from common stereotypes. In addition, participants' perceptions of the other stakeholder groups were found to be highly stereotypical and were not supported by the data. For. Sci. 45(1):62-73.
Realized Gain and Prediction of Yield with Genetically Improved Pinus radiata in New Zealand
Authors: Carson Susan D. , Garcia Oscar , Hayes Judy D.
Published: April 2024

Pinus radiata D. Don seedlots of varying genetic quality were compared in block-plot genetic-gain trials at 10 locations representing most of the site types in New Zealand. Permanent sample plots were measured annually for growth from age 6-8 yr from planting to ages 15-17 (midrotation). Seedlots from first-generation open-pollinated seed orchards and a mix of crosses that all involved the top-performing parent were, respectively, on average 4.5% and 5.3% taller and had 6% and 11% larger mean diameter, 12% and 30% more basal area, and 15% and 34% more stem volume than seedlots originating from mild mass selection in harvested stands ("climbing select"). The observed growth increases were quantified as changes in the rate of growth from that predicted by preexisting growth models in order to account for tree size and stocking differences. Seedlots from first-generation seed orchards and crosses of the top clone, respectively, grew 5.1% and 4.5% faster in height, and functions for basal area and stocking changed 13% and 26.4% faster, respectively, than the baseline growth models, which were based on climbing select. This implies that increased basal area growth must be taken into account in order to obtain accurate prediction of gain in stem volume. The incorporation of these observed increases in growth rates into stand growth models as "genetic-gain multipliers" in order to extrapolate predictions of growth of genetically improved seedlots beyond the sites, silvicultures, and seedlots represented in the genetic gain trials is discussed. For. Sci. 45(2):186-200.
Selecting Loblolly Pine Parents for Seed Orchards to Minimize the Cost of Producing Pulp
Authors: Lowe W. J. , Byram T. D. , Bridgwater F. E.
Published: April 2024

Southern pine cooperative breeding programs currently emphasize genetic improvement of growth rates. When a deployment population, typically a seed orchard, is established, there is an opportunity to emphasize traits other than growth rate to maximize the profit of individual cooperators in the breeding program. We studied a Southeast Texas breeding population and developed selection indexes to optimize profits for Kraft and mechanical pulp mills. The relative economic weights for volume and wood density were 1:8.1 and 1:8.6 for Kraft and mechanical pulp mills, respectively. Choosing parents with these indexes increased expected profit per ton of dry pulp by 3.4% for both mill types. Expected gains in profit were 3.3% when parents were chosen based on wood density alone. If parents were chosen based solely on volume growth, expected gains in profit were only 0.3%--0.4%. For. Sci. 45(2): 213-216.
Projecting Timber Inventory at the Product Level
Authors: Teeter Lawrence , Zhou Xiaoping
Published: April 2024

Current timber inventory projections generally lack information on inventory by product classes. Most models available for inventory projection and linked to supply analyses are limited to projecting aggregate softwood and hardwood. The research presented describes a methodology for distributing the volume on each FIA (USDA Forest Service Forest Inventory and Analysis) survey plot to product classes given a type characterization, volume, and average dbh (diameter at breast height, 1.37 m above average ground level) for the plot. A multinomial logit model was developed to estimate sets of product proportion functions to distribute plot volumes by product class for each forest type and size class. A discussion of the performance of the model using Alabama and Mississippi FIA plot level data is provided. For. Sci. 45(1):226-231.
An Analysis of Monte Carlo Integer Programming, Simulated Annealing, and Tabu Search Heuristics for Solving Spatial Harvest Scheduling Problems
Authors: Boston Kevin , Bettinger Pete
Published: April 2024

Heuristics are commonly used to solve spatial harvest scheduling problems. They can generate spatially and temporally feasible solutions to large problems that traditional mathematical programming techniques are unable to solve. A common complaint about heuristics is that the quality of the solutions is unknown. We compared three heuristic techniques commonly used to solve spatial harvest scheduling problems: Monte Carlo integer programming, simulated annealing, and tabu search. Five hundred solutions to four problems, which had between 3000 to 5000 0-1 integer variables, were generated with each heuristic technique. In addition to the heuristic solutions, the optimal solution value was found to each problem using integer programming. Simulated annealing found the highest solution value for three of the four planning problems, and was less than 1% from the highest objective function value in the fourth problem. Tabu search located the best solution for the fourth planning problem. Monte Carlo integer programming had the lowest objective function for all four problems. Tabu search had the smallest range of solutions, followed by simulated annealing. Monte Carlo integer programming had the largest range of solutions. Using the Anderson-Darling statistics, the hypothesis that the solutions from each heuristic technique were distributed as a Weibull distribution was rejected for 10 of the 12 set of values. For the two solutions where the Weibull distribution was not rejected, the estimated optimal solution was found to be an unreliable estimate of the actual optimal solution. It appears that the reliability of using extreme value statistics to estimate the optimal solution is dependent on the quality of solutions generated by the heuristic procedure. For. Sci. 45(2):292-301.
Regional Distribution and Dynamics of Coarse Woody Debris in Midwestern Old-Growth Forests
Authors: Spetich Martin A. , Shifley Stephen R. , Parker George R.
Published: April 2024

Old-growth forests have been noted for containing significant quantities of deadwood. However, there has been no coordinated effort to quantify the deadwood component of old-growth remnants across large regions of temperate deciduous forest. We present results of a regional inventory that quantifies and examines regional and temporal trends for deadwood in upland old-growth forest remnants within Indiana, Illinois, Missouri, and Iowa. From 1992 to 1994, down wood ≥ 10 cm in diameter and standing trees ≥ 10 cm dbh were inventoried on 328 one-tenth ha plots at 12 sites. The mean ratio among the sites by diameter class of the number of standing dead to standing live trees (dead/live ratio) ranged from 0.08 to 0.11 and was consistent for trees ≤ 65 cm in diameter. The dead/live tree ratio was generally greater for old-growth than for mature second-growth forests (70 to 90 yr old). Mean volume of standing dead trees across all old-growth sites was 21.4 m³/ha and down wood was 60.4 m³/ha. However, both standing and down wood volume (total deadwood) increased along a regional gradient of increasing productivity from southwest Missouri to northeast Indiana and also increased with increasing age of dominant and codominant trees. Old-growth forests on high productivity sites averaged more pieces/ha of down wood in all diameter classes and higher volume/ha of down wood in nearly all diameter classes than did old-growth forests on low productivity sites. A chronosequence of forests from 10 yr to more than 200 yr since stand establishment indicated a sharply declining down wood volume from age 10 to 70 yr followed by increasing volume between 80 and 200 yr. For. Sci. 45(2):302-313.
Age-Related Changes in Production and Below-Ground Carbon Allocation in Pinus Contorta Forests
Authors: Smith Frederick W. , Resh Sigrid C.
Published: April 2024

A decline in wood production and above-ground net primary production (ANPP) following an early maximum is a widely observed feature of forest development. Why should relatively young, seemingly vigorous even-aged forests undergo this decrease in production? We measured above-ground net primary production and below-ground carbon allocation in an age sequence of lodgepole pine forest in south-central Wyoming spanning 260 yr of forest development. ANPP and total root carbon allocation (TRCA) are examined to determine if there is an increase in TRCA of sufficient magnitude to offset the observed decrease in ANPP in developing lodgepole forests. Also, we examined changes in canopy structure, leaf area efficiency (E), and above-ground carbon allocation patterns to determine their potential role in the age-related decrease in ANPP.

ANPP declined by 50% between peak production of 192 gC m-2yr-1 at age 30 to 92 gC m-2yr-1 at age 260, largely as a decrease in stemwood production. TRCA was similar for forests from 30 to 100 yr old, but was significantly less in 260-yr-old forest at 391 gC m-2yr-1 than in younger lodgepole forests at 516 gC m-2yr-1. Declining ANPP was not due to an increase in carbon allocation to below-ground production. Net primary production (NPP), the total of above-ground and below-ground NPP, declined by 36% from 450 gC m-2yr-1 at age 30 to 288 gC m-2yr-1 at age 260. This progressive decline in NPP was associated with changes in stand structure that occur during stand development, including decreased leaf area, shifting carbon allocation, and decline in leaf area efficiency. Our results suggest that a combination of several factors, acting in concert, produce the observed decline in ANPP associated with the development of even-aged lodgepole pine forests. For. Sci. 45(3):333-341.
A Framework for Designing Forest Subsidies: Linking Landowner and Regional Impacts in the Mississippi Delta
Authors: Sullivan Jay , Amacher Gregory S.
Published: April 2024

We examine the economic impacts of land use shifts from agricultural to forestry production in the Mississippi Delta at both landowner and regional economy levels. The economic impacts that we consider include net revenues to farmers who convert Delta soybean lands to forest, and the changes employment, income, value added, industry output, and taxes that we expect to occur across a three state regional economy. We develop a framework that links these landowner and regional impacts in order to compare economic impacts of land use changes at landowner and regional levels, and to investigate the self-financing potential of subsidies. Results at the landowner level indicate that conversion may provide positive returns on better soils for some tree species. Results at the regional economy level indicate that the impacts would be generally negative, although landowner subsidies are computed that could equalize the regional impacts of forestry and soybean production. Further, for limited combinations of tree species and soil type, landowner subsidies could be self-financing, providing tax revenues that could offset government outlays. Our results imply that if subsidies were adopted, they should target species and site conditions. For. Sci. 45(3):381-393.
Arbitrage-Free Valuation of a Federal Timber Lease
Authors: Burnes Ellen , Thomann Enrique , Waymire Edward C.
Published: April 2024

The objective of this paper is to describe a quantitative framework for offering timber harvest bids on federal lands which includes special considerations of the volatility of timber indices and the harvesting costs involved in harvesting timber. The advantage of such an approach is that it provides a precise framework in which various underlying considerations, such as volatility and cost, may be systematically defined, measured, and evaluated. The valuations derived in this paper provide a market standard against which additional value that encompasses social or environmental welfare may be evaluated. We discuss a specific USDA Forest Service timber sale as a case study to illustrate this approach. For. Sci. 45(4):473-483.
Relating Site Index to Ecological Factors in Black Spruce Stands: Tests of Hypotheses
Authors: Beaumont Jean-François , Ung Chhun-Huor , Bernier-Cardou Michè
Published: April 2024

Modeling dominant height through site index, defined as dominant height at some fixed tree age, requires two equations. The site index must be estimated as the average height of dominant trees at base age, and dominant height must be modeled as a function of age and site index, each model having its own error term. This raises a problem when squared errors are minimized to estimate parameters of interest: the estimates are biased and inconsistent because the error terms are correlated with the explanatory variables. Two additional problems are the autocorrelation among error terms and variance heterogeneity within trees. The generalized method of moments (GMM), which simultaneously takes these problems into account, offers a tool to estimate parameters of the site index and dominant height equations consistently and without bias. Allowing parameters of the height growth model to depend on explanatory variables representing ecological region and drainage class provides useful insight into growth patterns, and improves prediction based on these models. A simulation study confirms that the GMM combined with prewhitening of the time series for each tree produces useful estimates of the parameters and valid statistical tests of hypotheses about their value. For. Sci. 45(4):484-491.
Stochastic Representation of Fire Behavior in a Wildland Fire Protection Planning Model for California
Authors: Gilless J. Keith , Fried Jeremy S.
Published: April 2024

A fire behavior module was developed for the California Fire Economics Simulator version 2 (CFES2), a stochastic simulation model of initial attack on wildland fire used by the California Department of Forestry and Fire Protection. Fire rate of spread (ROS) and fire dispatch level (FDL) for simulated fires "occurring" on the same day are determined by making coordinated draws from compound distributions characterizing 2 PM fire behavior indices such as ROS, then adjusting these draws using diurnal adjustment coefficients derived from hourly fire weather observations. Statistical examination of historical fire occurrence and predicted behavior data validated CFES2's use of independent fire occurrence and fire behavior modeling processes. For. Sci. 45(4):492-499.
Evidence of Resistance to the Pitch Canker Pathogen (Fusarium circinatum) in Native Stands of Monterey Pine (Pinus radiata)
Authors: Storer Andrew J. , Bonello Pierluigi , Gordon Thomas R. , Wood David L.
Published: April 2024

Resistance of Monterey pine, Pinus radiata, to pitch canker, caused by Fusarium circinatum, was investigated in a naturally regenerated native stand and a planted stand on the Monterey Peninsula, California. A dose of 125 spores was selected to test resistance as it produced significant differences in mean lesion length among trees. The resistance ranking of trees remained comparable when inoculated three times over a period of seven months, but the mean lesion length decreased with each inoculation. Lesion lengths were positively correlated with symptom development. In the naturally regenerated stand, 30% of the trees formed lesions less than 5 mm long and were considered resistant to the pathogen. In contrast, only 5% of trees in the planted stand formed lesions less than 5 mm long. The use of prescribed burning of Monterey pine stands to augment natural regeneration allows a wider expression of genetic diversity in the new host populations on which natural selection in favor of resistant genotypes can be imposed by the pathogen. For. Sci. 45(4):500-505.
A New Algorithm for Stand Table Projection Models
Authors: Cao Quang V. , Baldwin V. Clark
Published: April 2024

The constrained least squares method is proposed as an algorithm for projecting stand tables through time. This method consists of three steps: (1) predict survival in each diameter class, (2) predict diameter growth, and (3) use the least squares approach to adjust the stand table to satisfy the constraints of future survival, average diameter and stand basal area. The new method was evaluated against the Weibull parameter-recovery approach and another stand table projection method, using data from direct-seeded stands of loblolly pines (Pinus taeda L.). The constrained least squares method provided the best goodness-of-fit statistics (K-S, χ², and an error index) that were significantly different from those produced by the other two methods. This new algorithm can be employed in cases where diameter data do not necessarily follow the Weibull distribution. For. Sci. 45(4):506-511.
Seedling Leaf Structure of New England Maples (Acer) in Relation to Light Environment
Authors: Ashton P. Mark S. , Yoon Hae Soon , Thadani Rajesh , Berlyn Graeme P.
Published: April 2024

Seedling leaves of the genus Acer from southern New England were compared in relation to light. The species investigated were red maple (A. rubrum L.), a species tolerant of xeric and hydric sites; silver maple (A. saccharinum L.), a species restricted to riparian sites that are periodically flooded; and sugar maple (A. saccharum Marsh.), a mesic species of lower slopes and valleys. Germinating seedlings of all species were collected and grown within four shade treatments that had contrasting light quantity and quality: (1) approximately 100% of full sunlight, red:far-red ratio = 1.27; (2) 40% of full sunlight, ratio = 0.97; (3) 15% of full sunlight, ratio = 0.85; and (4) 4% of full sunlight, ratio = 0.46. Leaves, cuticles, and epidermal and palisade mesophyll cell layers were all thicker, and stomatal densities were higher for all three species in the full sun treatment. Dimensions of leaf structure (leaf thickness, palisade mesophyll thickness, lower epidermal thickness) were between 25 and 35% smaller for silver maple as compared to the other maples. Silver maple also allocated less biomass to roots (about 15% less) and more to stems. Its thin upper surface cuticle, thin leaves, and large leaf area predispose this species to desiccation. Phenotypic plasticity of leaf anatomical measures was greatest for red maple, suggesting it to be more of a generalist than its congeners. Red maple allocated greater biomass to roots in shade (17% and 27% more than sugar and silver maple respectively), with thicker leaves and cuticle, making it least prone to desiccation. Sugar maple had greater dry mass and total leaf area in the deepest shade than the other maples. Measures of leaf structure can provide useful insights into known ecological affinities of site and shade-tolerance among maples. For. Sci. 45(4):512-519.
Testing the Forest Rotation Model: Evidence from Panel Data
Authors: Kuuluvainen Jari , Tahvonen Olli
Published: April 2024

The effects on harvesting decisions of intertemporal and parametric changes in prices and forest owners' nonforest income are investigated using panel data. A behavioral timber supply function is derived using a utility-based rotation model, where the forest owner decides an optimal harvesting date for an even-aged stand simultaneously with his optimal life cycle consumption and savings. Capital markets are perfect and forests are valued in situ. The effects of intertemporal changes in the exogenous variables on the annual harvest are estimated using a fixed-effects tobit model and a sample of 119 Finnish farmer-forest owners in 1982-1991. The intertemporal effect on supply of timber price is positive while the effect of nonforest income is negative. The parametric effects of price and income levels on life cycle harvest, as measured by the average annual harvest per hectare over the sample period, are studied by using the estimated fixed effects and the individual sample means of exogenous variables. The parametric effect of the timber price level is negative and that of nonforestry income level positive. These signs are predicted by the utility-based rotation model, provided forests are valued in situ and the average harvest age is lower than that of maximum sustainable yield. For. Sci. 45(4):539-551.
Prediction of Annual Diameter Growth and Survival for Individual Trees from Periodic Measurements
Authors: Cao Quang V.
Published: April 2024

It is difficult to fit annual tree survival and diameter growth models to data that were measured, not every year, but at some interval. This study aimed to determine suitable methods to obtain parameter estimates for such a system from periodic measurements. Given a system consisting of a tree survival model and a tree diameter growth model, this article presents an iterative method for estimating system parameters. The method involves sequentially updating of the parameters of both models within the growth period. Data from 111 plots from the Southwide Seed Source Study of loblolly pine (Pinus taeda L.) were then used to evaluate this iterative approach against the averaging method that assumes a constant tree survival probability and diameter growth rate during the remeasurement interval. Results indicated that the iterative method out-performed the averaging method in predicting future individual tree survival, diameter growth, and stand basal area. The iterative method was superior because it accounted for the variable rate of diameter growth and tree survival probability as functions of ever-changing stand and tree attributes. For. Sci. 46(1):127-131.