bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth Response and Drought Susceptibility of Red Spruce Seedlings Exposed to Simulated Acidic Rain and Ozone
Authors: Lee Woong S. , Chevone Boris I. , Seiler John R. 
Published: April 2024

Abstract
One-year-old seedlings of red spruce were exposed to O3 (≤0.025 or 0.10 μl 1-1, 4 h d-1, 3 d wk-1) in combination with simulated rain (pH 5.6 or 3.0, 1 h d-1, 2 d wk-1, 0.75 cm h-1) for 10 weeks. After pollutant treatments, seedlings were subjected to two successive drought cycles. Whole-plant fresh weight increment (FWT) and dry weight were reduced after O3 exposure, whereas FWT and shoot height growth were increased after simulated rain exposure at pH 3.0 compared to pH 5.6. No interaction between O3 and rain treatments was observed for any growth variable measured. Foliar concentrations of K and S were greater in seedlings exposed to simulated rain at pH 3.0 compared with those at pH 5.6. Root hydraulic conductivity was highest in seedlings exposed to 0.10 μl 1-1 O3 + pH 3.0 rain solution compared with all other treatments after the first drought cycle. There were no significant O3 effects on net photosynthesis (Pn), transpiration or water-use efficiency prior to the drought cycles. However, during the second drought cycle, Pn was more sensitive to branch water potential in seedlings exposed to 0.10 μl 1-1 O3 + pH 3.0 solution compared with seedlings exposed to low O3 + pH 5.6 solution. For. Sci. 36(2):265-275.
Growth and Biomass Partitioning Response of Northern Red Oak Genotypes to Shading and Grass Root Competition
Authors: Kolb T. E. , Steiner K. C. 
Published: April 2024

Abstract
First-year biomass, biomass relative growth rate, and biomass partitioning among organs were compared among eight open-pollinated families of northern red oak (Quercus rubra L.) under crossed levels of light intensity (100% and 37% full sun) and grass root competition [presence and absence of grass roots (Poa pratensis L.)]. Ontogenetic patterns of biomass partitioning during the first year of seedling development were characterized by coefficients of the allometric equation Y = aXb. Grass root competition reduced seedling biomass at both levels of light intensity. Shading reduced seedling biomass in the absence of grass but had no effect in its presence. Total biomass and biomass relative growth rate differed among families, and family X environment interaction variance was negligible compared to family variance. Results suggest that families with superior juvenile growth rate under competition-free conditions will also have superior growth rate under at least some conditions of shading and root competition. Biomass partitioning to leaf area, and to shoot weight relative to root weight declined during seedling development. Both shoot-root ratio and leaf area ratio were greater in shaded compared to full sun environments, while the presence of grass root competition had an opposite effect on both ratios. Families differed in shoot-root ratio, and shoot-root ratios of families responded differently to grass root competition. However, family differences in biomass partitioning were not consistently related to family differences in growth rate in any environment. For. Sci. 36(2):293-303.
U.S. Trade in Transition—An Econometric View of South Sea Wood Flows
Authors: Cengel Dennis , McKillop William 
Published: April 2024

Abstract
There were distinct stages of growth and development in the 1960s and 1970s in the flow of South Sea tropical hardwood as it made its way from the forests of Indonesia, East Malaysia, and the Philippines to the transit plywood-manufacturing plants of Japan, South Korea, and Taiwan, and thence to U.S. markets. In the introductory stage, the dominant end-use was flush-doors, the dominant manufacturer was Japan, and the dominant provider of logs was the Philippines. The expansionary phase started in the early 1960s and was characterized by a dramatic rise in South Korean and Taiwanese plywood exports which found distinct niches in the U.S. market. By its end, in the early 1970s, these countries supplied, respectively, 60% and 30% of U.S. demand. A quasi-spatial econometric model was used to investigate plywood and log flows over the 1962-1979 period. The consequences of SEALPA log export restrictions that started around 1980 were analyzed using estimated reduced-form relationships and a gap-type model. Future U.S. imports of South Sea plywood are expected to be around 60% of the peak level reached in the early 1970s, with more than 80% of them coming from Indonesia. For. Sci. 36(2):425-437.
An Analysis of Three Methods for Fitting Site-Index Curves
Authors: Furnival George M. , Gregoire Timothy G. , Valentine Harry T. 
Published: April 2024

Abstract
The analysis of covariance method, the method of algebraic differences with all possible differences, and the method of weighted parameter prediction are shown analytically to be identical for fitting a site-index equation that can be transformed into a simple linear model. Results of the analysis apply to both anamorphic and polymorphic systems, which are linear in the parameters. For. Sci. 36(2):464-469.
Relationships Among Humus Forms, Forest Floor Nutrient Properties, and Understory Vegetation
Authors: Klinka K. , Wang Q. , Carter R. E. 
Published: April 2024

Abstract
Morphologically characterized humus forms and their associated understory vegetation have been used to infer different modes of decomposition of forest floor materials, but few studies have analyzed relationships among humus forms, forest floor nutrient properties, and understory vegetation. Examination of these relationships was accomplished in this study by a numerical analysis of forest floor and vegetation data that were obtained from 151 cool mesothermal forest ecosystems of southern British Columbia and stratified into seven humus form groups. Four forest floor nutrient properties (pH, C/N ratio, total N, and sum of exchangeable Ca, Mg, and K) and nine diagnostic combinations of species differentiated the groups. pH and mineralizable-N consistently increased, and C/N ratio consistently decreased from Lignomors to Hemimors, Humimors, Mormoders, Leptomoders, and to Vermimulls, indicating the presence of a regional decomposition gradient. Multivariate summaries of the nutrient properties and diagnostic species were highly correlated. A consistent correlation was also found between the nutrient properties and indicator plants of nitrogen-rich soils. For. Sci. 36(3):564-581.
Species Substitution and Tropical Log Imports by Japan
Authors: Vincent Jeffrey R. , Gandapur Alamgir K. , Brooks David J. 
Published: April 2024

Abstract
Tropical rainforests contain many "lesser known species" that have not achieved widespread acceptance in international timber markets. This paper provides a quantitative analysis of the effects on tropical log demand of two economic factors: relative prices and technical change. A multi-output cost function framework is developed to analyze tropical log demand as derived from the production of plywood and sawnwood. Data analyzed are Japanese imports of dipterocarp and nondipterocarp logs (proxies for well- and lesser known species, respectively) from the South Seas during 1970-87. The econometric results indicate that the composition (dipterocarp vs. nondipterocarp) of tropical log imports was not significantly influenced by either relative prices or technical change during the period analyzed. For. Sci. 36(3):657-664.
Shifting Southern Softwood Stumpage Supply: Implications for Welfare Estimation from Technical Change
Authors: Newman David H. 
Published: April 2024

Abstract
This paper estimates the economic benefits from increasing timber inventory in the southern softwood forest over the period from 1950 to 1980. The analysis measures the benefits arising to consumers and producers of stumpage from increases in softwood stumpage availability. Over the period of the analysis, average total benefits are roughly equal between the pulpwood and solidwood (combined lumber and plywood) stumpage markets. Average combined benefits range from $1.3 million to $5.3 million per year (1967 $). The size of the total benefits are more greatly affected by the level of shift assumed than they are by the structural characteristics of the market. The distribution of the benefits, however, differs quite markedly depending on the market structure. Pulpwood consumers (pulp and paper mills), for instance, receive greater than 150% of the total benefits from increased productivity effects on stumpage production as producers receive negative benefits. Solidwood producers receive positive benefits from increasing supply, although only 10% of the total benefits that are created. These distributional imbalances in the effects of policies designed to improve forest productivity should be considered in future analyses which assess the impacts and returns of these policies. For. Sci. 36(3):705-718.
Nutrient Leaching of a Loblolly Pine Forest Floor by Simulated Rainfall II. Environmental Factors
Authors: Duffy P. D. , Schreiber J. D. 
Published: April 2024

Abstract
A multiple-intensity simulator was used to apply 25.4 mm of simulated rainfall to forest floor samples (L and F. horizons) collected from a loblolly pine plantation and placed in l-m² pans. Leachate (rainfall that flowed through the forest floor) was sampled at intervals during each application. As simulated rainfall and forest floor materials temperature were increased from 8°C to 35°C, the PO4-P, NH4-N, and TOC concentrations in leachate increased about twofold. In contrast, NO3-N concentrations were independent of rainfall temperature. In a series of five simulated storms over a 27-day period, nutrient concentrations in leachate collected on the 27th day were only 16% to 41% of those sampled in the storm on the first day. Nutrient concentrations in leachate from simulated acid rain (pH 4.2) were similar to those produced by deionized water (pH 5.3). Within individual simulated storms, nutrient concentrations in leachate rapidly increased to a maximum and then decreased to a near constant value as the storm progressed. After maximum concentrations, the function C = aTb best described the relationship of concentration (C) with time (T); the function C = aebQ best described the relationship of concentration (C) with cumulative leachate volume (Q). Quantification of environmental influences on forest floor nutrient leaching, as described in this report, should aid nutrient cycling and water quality modeling. Results demonstrate that the rainfall simulator is a useful tool to study leaching kinetics. For. Sci. 36(3):772-789.
Hybrid Econometric/Input-Output Modeling of the Cumulative Economic Impact of National Forest Harvest Levels
Authors: Sullivan Jay , Gilless J. Keith 
Published: April 2024

Abstract
Econometric and input-output methods are combined to assess the multiforest personal income impacts of timber harvesting activities on regional economies in Northern California. The importance of a combined assessment is demonstrated using data from the El Dorado and Shasta-Trinity national forests. Depending upon the timber harvest levels of other national forests in the area, projected changes in personal income resulting from a change in harvest level on either forest varied by as much as 27%. For. Sci. 36(4):863-877.
An Investigation of the Rule-of-Thumb Method of Estimating After-Tax Rates of Return
Authors: Campbell Gene E. , Colletti Joe P. 
Published: April 2024

Abstract
The effect of income taxes may significantly alter an investment's expected profitability relative to competing alternatives. With one exception, both post-tax cash flows and a post-tax discount rate must be used if the effects of taxation are to be correctly incorporated into an investment analysis. The adjustment of the pre-tax discount rate to a post-tax rate often is accomplished by using an estimate derived by rule-of-thumb. This estimate (effectively reducing the pre-tax rate by the product of itself and 1 minus the marginal income tax rate) is accurate only when the alternative used to determine the opportunity cost of capital involves a nondepreciating asset, returning equal annual payments, whose salvage value is exactly 100% of first cost, or where the alternative investment's life is equal to 1 year. For alternatives with depreciable, depletable, or tax-deferred assets, the rule-of-thumb estimate is not accurate. Its accuracy depends on the alternative's real rate of return, the investor's marginal income tax rate, the level of inflation, and the investment period. In general, the rule-of-thumb method's accuracy decreases as the real rate of return decreases and as the income tax rate, inflation, and investment period increase. In addition, its accuracy is further decreased as depreciation or depletion is accelerated, or if an investment tax credit is included as part of the expected income stream. For. Sci. 36(4):878-893.
Nonlinear Programming Approaches to Multistand Timber Harvest Scheduling
Authors: Hof John G. , Kent Brian M. 
Published: April 2024

Abstract
This paper describes several nonlinear programming formulations of multistand (analysis area) timber harvest scheduling problems and compares these formulations with more traditional approaches. The strengths of the nonlinear programming approaches include the abilities to represent explicit nonlinear timber yield functions and to define continuous harvest timing variables. Optimal control theory has these capabilities but, to date, the technique has not proven applicable to multistand problems or to problems with common exogenous constraints. Linear programming works well with multistand problems but utilizes piecewise approximations of yield functions and discrete time periods. Both nonlinear and linear programming can accommodate common programming constraints such as output targets and limits on inputs. The nonlinear programming formulations were solved using a version of the generalized reduced gradient algorithm. It was discovered that a local optimum exists for each number of harvests on each analysis area. Because nonlinear programming finds local optima, the global optimum was determined with multiple advanced starts. A nonlinear programming formulation that can handle time-period-based constraints is provided, but could not be solved. For. Sci. 36(4):894-907.
Winter Injury Susceptibility and Cold Tolerance of Current and Year-Old Needles of Red Spruce Trees from Several Provenances
Authors: DeHayes D. H. , Waite C. E. , Ingle M. A. , Williams M. W. 
Published: April 2024

Abstract
Winter injury to red spruce (Picea rubens Sarg.) trees from 12 provenances in a plantation near Colebrook, NH, was described and quantified in spring 1986 through 1989. Winter injury was found exclusively on current-year needles (i.e., buds and twigs were virtually uninjured), and 34% to 68% of trees were injured each year. Laboratory assessments of cold tolerance of current and year-old needles of trees representing four red spruce and four balsam fir (Abies balsamea [L.] Mill.) provenances indicated that current-year needles of red spruce, but not balsam fir, were 8° to 12°C less cold tolerant than year-old needles in late autumn and early winter. Also, throughout the winter, current-year needles of red spruce were about 10°C less cold tolerant on average than those of balsam fir, a sympatric species that does not suffer winter injury. Thus it appears that a "window" of freezing injury susceptibility exists naturally for red spruce in early winter. Provenance differences in foliar winter injury and percentage of trees injured were highly significant in 1986, 1987, and 1989, and marginally significant in 1988. Trees from Quebec, New York, and New Brunswick were consistently among the least injured each winter, whereas trees from Massachusetts and New Hampshire were consistently among the most injured. It is likely that repeated winter injury is a major contributor to the reported decline of red spruce in northern forests. For. Sci. 36(4):982-994.
Integrating Short-Term, Area-Based Logging Plans with Long-Term Harvest Schedules
Authors: Nelson John , Brodie J. Douglas , Sessions John 
Published: April 2024

Abstract
Procedures are developed and evaluated for integrating short-term, area-based plans with long-term, strata-based harvest schedules. A combination of these two approaches to forest planning provides a spatially feasible, short-term solution that can also incorporate strategic harvest goals over a long-term period. Three basic steps are used to combine the area and strata-based plans: (1) a 15-decade strata-based plan is solved with linear programming (LP) to establish strategic harvest goals; (2) with these goals as guidelines, 3-decade, area-based plans are generated with a random search technique caned Monte-Carlo integer programming (MCIP); and (3) those area-based plans become the first 3-decade solution within 15-decade integrated plans that are solved with LP. Both the harvest units and the road projects within the area-based plan are specified as strict binary variables.
MCIP is an effective technique for generating feasible solutions to integer problems encountered in area-based planning. Although no guarantee of optimality can be assured, the technique is a major improvement over manual methods, and it is a practical alternative to mixed-integer programming for identifying feasible alternatives.
In comparison to the integrated plans, it was found that the strata-based model consistently overestimated long-term revenues, and consistently underestimated long-term volumes. The integrated plans produced net revenue and volume levels within 10% of the strategic goals established by the strata-based linear program. The case study was conducted in 1987-88 on a forest located in British Columbia. For. Sci. 37(1):101-122.
Availability, Quality, and Selection of Browse by White-Tailed Deer after Clearcutting
Authors: Hughes Jeffrey W. , Fahey Timothy J. 
Published: April 2024

Abstract
We evaluated the effect of large-scale forest harvest on the production, nutritive quality, twig size, and use of four preferred species of browse by white-tailed deer in a spruce-fir forest in New Hampshire. Red maple produced the most new twigs (44-fold increase 3 years after harvest), and 99% of these were sprouts from stumps. Mountain maple and mountain ash twig production increased by factors of 3.5 and 1.9, respectively, and most twigs were borne on stems that survived the clearcutting. Most yellow birch (4-fold increase after 3 years) colonized from newly dispersed seed. For all species of browse except yellow birch, clearcutting resulted in (1) significantly larger, heavier twigs, and (2) significantly higher concentrations of protein and soluble carbohydrates. Deer removed a higher proportion of twigs from the clearcut than from the uncut forest. Mountain ash and mountain maple were the preferred species on both sites. Management implications are discussed. For. Sci. 37(1):261-270.
Transportation Specification in Forest Trade Models
Authors: Krutilla Kerry 
Published: April 2024

Abstract
Computable spatial equilibrium models in the forestry literature are based on an analytic simplification of the transportation sector. This paper evaluates whether the usual transportation specification can cause biased economic estimates of trade policy actions implemented in forestry markets. The analysis reveals that estimates of tariff policy actions in fact can be sensitive to the transportation specification. This leads to some conclusions about the interpretation of economic estimates generated by spatial equilibrium forestry trade models. For. Sci. 37(1):284-295.
Genetic Gains in Growth and Simulated Yield of Pinus monticola
Authors: Rehfeldt G. E. , Wykoff W. R. , Hoff R. J. , Steinhoff R. J. 
Published: April 2024

Abstract
Between years 7 and 25, genetic variances for height and diameter have increased in 29 full-sib western white pine (Pinus monticola Dougl.) families planted on two sites. Family differences in height were statistically significant throughout most of the period, while differences in breast-high diameter were detected after year 13. Estimated heritabilities for height were relatively constant, averaging 0.11 and 0.33 for individuals and families, respectively; those for diameter have generally increased throughout the period and by year 25 had reached 0.14 for individuals and 0.43 for families. These heritabilities coupled with relatively large phenotypic variances suggest that programs of forward selection should provide genetic gains of about 7% in the height or 9% in the diameter of individual trees in year 25. Genetic correlations of height at various ages with stem volume in year 25 were high (&gt;0.85), as were the correlations involving diameter and 25-yr volume after year 13. Correlated responses to selection suggested that year 7 would be the most efficient time to select, providing 85% of the maximum gain available in 25-yr volume. A stand simulation model was used to project the yields (volume per acre) expected from the progenies of selections made in year 7. Results of the simulations suggested that the amount of increase in yield depended on the density, rotation length, and manner by which genetic gains accrue beyond year 25. The results implied that relatively small gains in the attributes of 25-yr-old trees can result in either increased volumes per acre for a given rotation or decreases in the rotation to achieve a given volume. For. Sci. 37(1):326-342.
Soil Nitrogen Changes Associated with Slash Pile Burning in Pinyon-Juniper Woodlands
Authors: Covington W. Wallace , DeBano Leonard F. , Huntsberger Thomas G. 
Published: April 2024

Abstract
A combination of a time sequence and an experimental approach, both with repeated measurements, was used to determine the effects of slash pile burning in a pinyon-juniper woodland. Results showed that burning caused mediate increases (approximately 50-fold) in soil ammonium concentrations. Nitrate concentrations were not immediately affected; however, by one year after burning, nitrate concentrations were approximately 20 times higher where piles had been burned than in unburned controls. These increases in inorganic nitrogen disappeared by year 5 after burning. Such a combination of repeated measures with both a time sequence approach and an experimental approach offer a procedure for rapidly estimating long-term response functions in forest research. For. Sci. 37(1):347-355.
Radial Enlargement of Mortality Centers Caused By Arceuthobium pusillum Peck in Black Spruce Stands
Authors: Baker F. A. , French D. W. 
Published: April 2024

Abstract
Sequential aerial photography of dwarf mistletoe (Arceuthobium pusillum infested black spruce stands (Picea mariana [Mill.] BSP.) was used to measure the radial enlargement of circular mortality centers. Site index and stand density had no effect on the average 4.7 ± 3.3 ft/yr expansion rate. Methods for determining spread rates are discussed. For. Sci. 37(1):364-367.