bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Limiting Foliar Biomass in Conifer Plantations from Allometric Relationships and Self-Thinning Behavior
Authors: Blake John , Somers Greg , Ruark Greg 
Published: April 2024

Abstract
The ability of forest stands to sustain increasing amounts of foliage biomass is related in a positive manner to both aboveground woody biomass and to site productivity. Knowledge of the limit to sustainable foliar biomass at a given level of photosynthetically active radiation and under minimum environmental stress would have important implications for modeling primary forest productivity. Theoretical analysis and limited experimental data collected on even-aged plant populations that are undergoing self-thinning indicate that total stand foliar biomass should achieve a nearly constant value for a given species and site. Average diameter-plant density relations for various conifers species coupled with available foliage mass-stem diameter equations were used to approximate the maximum amount of foliage which could be sustained. Sources of bias and effects due to changes in specific leaf area are evaluated. The maximum foliage biomass calculated in this manner was subject to positive bias, but estimates at low densities correspond to values obtained empirically for mature stands growing under very favorable environmental conditions. Calculated estimates suggest that maximum sustainable foliage biomass increases slightly with decreasing plant density along the self-thinning line, in contrast to expectations. The magnitude of the increase depends upon the relative value of the self-thinning exponent compared to the exponent of the allometric equation. Changes in light distribution in relation to crown architecture, particularly crown depth and foliage clustering, may account for this effect. For. Sci. 37(1):296-307.
A Hierarchical Approach to Forest Planning
Authors: Weintraub Andrés , Cholaky Alejandro 
Published: April 2024

Abstract
We present a hierarchical approach for large-scale forest planning. It is based on solving an aggregate problem, which is of moderate size, at higher levels of derision. The results obtained lead to land allocations and input-output targets for the different zones of the forest. At a lower level of decision, based on the land allocation and input-output targets, each zone is modeled in a detailed way. These problems are again of moderate size. Consistency between the two levels of derision is preserved. The economic and algorithmic implications of this methodology approach are discussed. A test case is presented to show the feasibility of this approach. For. Sci 37(2):439-460.
Prediction Bias and Response Surface Curvature
Authors: Gertner George 
Published: April 2024

Abstract
Many functions used for forestry applications have response surfaces that have curvature. Depending on the degree of curvature, predictions made with these functions can be biased when the inputs to these functions have unbiased random errors. An approximation is presented for calculating the bias in prediction when there are unbiased but random errors in the inputs of the function. Examples of some fairly simple functions used in forestry are shown to provide highly biased predictions in typical applications. For. Sci. 37(3):755-765.
Genetic Parameter Estimates for Greenhouse Traits of Slash Pine Artificially Inoculated with Fusiform Rust Fungus
Authors: de Souza S. M. , White T. L. , Hodge G. R. , Schmidt R. A. 
Published: April 2024

Abstract
Six-week-old greenhouse-grown seedlings of 100 open-pollinated slash pine families were artificially inoculated with fusiform rest fungus in three testing periods at the USDA Forest Service Resistance Screening Center. SIX months after inoculation, seedlings were scored for symptoms of rest infection. Genetic parameters (heritabilities, genetic correlations and family x test interactions) were estimated for 16 traits. Eleven traits appear highly promising for inclusion into a selection index to predict breeding values for rest resistance in the field. For these 11 traits, family x test interaction was not important, family heritabilities were high (&gt;0.78), and differences among the four groups of families were minor for family variance, variance of family means, and heritability estimates. The other five traits had measurable amounts of family x test interaction and lower heritability estimates (&lt;0.70). For. Sci. 37(3):836-848.
Root Damage by the Conifer Swift Moth: A Mortality Factor in Montane Red Spruce Regeneration
Authors: Grehan J. R. , Paricer B. L. , Wagner D. L. , Rosovsky J. , Aleong J. 
Published: April 2024

Abstract
Red spruce seedlings potted with Korscheltellus gracilis (Lepidoptera: Hepialidae) larvae exhibited characteristic feeding damage, including localized removal of bark and cambium, and root girdling. Seedling damage resulted in a significant increase in needle dieback, and reductions in growth, root area, and root weight. A survey of population density and montane distribution of larvae and adults at Whiteface Mountain (New York) and Mount Moosilauke (New Hampshire) revealed significantly higher numbers at elevations of 900-1100 m compared to 500 m, 700 m, and 1300 m. Larval densities reached a maximum mean of 38/m² on Mount Moosilauke and 11/m² on Whiteface Mountain, with higher densities recorded from the windward slopes. The potential ecological significance of K. gracilis is discussed in relation to the problem of red spruce decline. For. Sci. 38(3):611-622.
Approximate Srivastava Estimation in Forestry
Authors: Ouyang Z. , Schreuder H. T. 
Published: April 2024

Abstract
Srivastava estimation formalizes the introduction of additional prior and posterior information in sampling to increase efficiency in estimation. An unbiased new estimator is given for Poisson sampling which is approximately as efficient as the standard slightly biased estimator without using any additional information.
The increased efficiency possible with this method or approximations to it are illustrated for Poisson sampling and point-Poisson sampling using simulations. Srivastava estimation may be applicable in many forest inventory situations. Besides efficiency, the seriousness of estimation bias and reliability of variance estimators need to be considered in all applications. FOR. SCI. 39(2):309-320.
Thirty-Seven Year Performance of Loblolly Pine Seed Sources in Eastern Maryland
Authors: Schmidtling R. C. , Froelich R. C. 
Published: April 2024

Abstract
Nine loblolly pine seed sources from The Southwide Southern Pine Seed Source Study were planted on the eastern shore of Maryland. After 20 yr, the local Maryland source had the highest yield, and the southernmost source, from Livingston Parish, LA, the lowest yield. At age 37, the Texas and Arkansas sources had the highest volumes and Maryland and Livingston Parish the lowest. The Maryland source had good height, but above-average mortality and small diameters. Texas and Arkansas sources, originating from areas where droughts are common, were below average in height at age 37, but yield was best because of better survival. These sources appear to be more tolerant of competition and less damaged by beetles after prolonged drought. Better regulation of stand density was needed to optimize yields of all seed sources. For. Sci. 39(4):706-721.
Do Fire Sizes Differ Between Southern California and Baja California?
Authors: Chou Yue Hong , Minnich Richard A. , Dezzani Raymond J. 
Published: April 2024

Abstract
This paper examines the methods employed in a previous study by Strauss et al. (1989) in which the authors suggested that the degrees of size inequality of large fires are much the same in southern California and Baja California, Mexico. We found that both the graphical method and the curve-fitting method employed in that study are inappropriate for comparing fire-size frequency distributions. Our examination of fire histories using the analysis of variance and the contingency table analysis indicates a significant difference in fire-size frequency between these regions. The result implies that spatial strategies of wildfire management must be established to minimize the potential of unnatural sizes and that management strategies should be focused on effective preventive treatments. For. Sci. 39(4):835-844.
Further Studies of Root Decomposition Following Harvest of a Northern Hardwoods Forest
Authors: Fahey Timothy J. , Arthur Mary A. 
Published: April 2024

Abstract
An earlier study of decomposition and nutrient release of root systems following harvest of a northern hardwoods forest ecosystem indicated uncertainties with regard to (1) possible experimental effects on decay of fine and woody roots and (2) patterns of woody root decay and nutrient release in the first several years of decay. Results of this study suggested that most fine roots in the forest floor died early in the first growing season after forest harvest, releasing much of their tissue K. In contrast, mineral soil roots either died much more slowly or were not effectively leached of K during most of the first summer. Rates of release of C and N from fine roots were similar, suggesting that previous studies using mesh bags bad either overestimated N release or underestimated C mineralization, or both. Earlier estimates of total N released from fine roots of northern hardwoods in the first 2 yr after harvest probably were too high. Rates of decay of large woody roots of northern hardwoods were high, with 45%-63% dry weight loss in 4 yr as measured with tethered roots, but this method probably overestimated decay by exposing cut ends to decay organisms. High variation in decay rates was associated especially with the site of incubation, as all the roots (independent of species and size class) incubated in a particular location decayed at about the same rate. For. Sci. 40(4):618-629.
Needlefall Returns and Resorption Rates of Nutrients in Young Intensively Managed Slash and Loblolly Pine Stands
Authors: Dalla-Tea Fernando , Jokela Eric J. 
Published: April 2024

Abstract
Annual needlefall (NF) returns and resorption rates of nutrients in 6-yr-old slash (Pinus elliottii Engelm. var. elliotti,) and loblolly (p. taeda L.) pine stands were investigated using a 2 x 2 x 2 factorial experiment (species, annual fertilization, sustained competition control) in north central Florida. Compared with the reference (untreated), the combination treatment (annual fertilizer plus competition control) increased NF N returns about 6.3-fold (from 2.5 to 15.8 kg ha-1) for slash pine and 13.3-fold (from 1.5 to 19.9 kg ha-1) for loblolly pine. Similar treatment effects were found for P, with recycling rates for loblolly pine greater than for slash pine. Absolute resorption rates of N (from 4.7 to 19.9 kg ha-1 for slash pine; 2.5 to 21.1 kg ha-1 for loblolly pine) and P (from 0.5 to 1.9 kg ha-1 for slash pine; 0.2 to 2.4 kg ha-1 for loblolly pine) increased for both species as management intensity increased (i.e., cultural treatments; reference vs. fertilizer plus competition control). However, specific resorption rates of N and P were lowest for fertilizer treatments. When averaged over all cultural treatments, slash pine resorbed more N (62 vs. 57%) and P (62 vs. 51%) than loblolly pine; approximately 26% of the annual P requirements for slash pine were met by reabsorption compared with 13% for loblolly pine. Nutrient pool size within the plant (uptake) and annual nutrient demands for growth were dominant factors influencing the nature and extent of N and P resorption for both pine species. For. Sci. 40(4):650-662.
Time Trends of Predicted Breeding Values in Selected Crosses of Coastal Douglas-fir in British Columbia: A Methodological Study
Authors: Magnussen S. , Yanchuk A. D. 
Published: April 2024

Abstract
Analytical techniques for estimating time trends and projections of breeding values from sparse data, unbalanced mating designs, and irregular assessments periods are presented and discussed. Time trends (ages 4 to 23) in genetic parameters of tree heights in 14-18 full-sib Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) crosses among six male trees from Coastal B.C. and six female trees from Washington and Oregon planted on four test sites on Vancouver Island were examined, and tentative projections of genetic gains were made. Annual height estimates were derived by fitting splines to height measures at ages 4, 7, 12, 18, and 23 yr. Genetic variances were derived from direct computations of covariances among all possible half-sib combinations; a method deemed superior to the conventional factorial analysis. Irregular fluctuations in genetic parameter estimates vanished after minor adjustments (&lt;1.5%) of variance-covariance matrices with negative eigenvalues. Sites effects were highly significant (P &lt; 0.001), but site-to-site correlations for pair-cross means were all nonsignificant (P &gt; 0.10). Additive genetic control of height growth was weak to moderate (h² ≈ 0.1, but generally increasing with age). The best genetic discrimination was observed on the more productive sites. A stable ranking of full-sib family means was reached at age 7 yr on one site versus age 18 for the other sites. Trends in breeding values were described with a mixed linear autoregressive time series model from which 10-yr projections were made. Projections took into consideration both the error structure surrounding the breeding values and the errors of the parameter estimates in the time series model. Selection of the best parent out of six for breeding and deployment on a single site type would generate an expected gain of about 2-5% in height growth between ages 4 and 23 yr. For. Sci. 40(4):663-685.
Spatial Characteristics of Diameter and Total Height in Juvenile Loblolly Pine (Pinus taeda L.) Plantations
Authors: Liu Jiping , Burkhart Harold E. 
Published: April 2024

Abstract
The spatial characteristics of diameter at breast height and total height were analyzed using data collected from a set of spacing trials planted with loblolly pines. These spacing trials were established at four locations in the Piedmont and Coastal Plain regions of Virginia and North Carolina in 1983. Trend surface analysis was employed to separate the systematic microsite variation from the variation incurred by intertree competition, and a simulation study was carried out to derive an empirical distribution for Moran statistics calculated from regression residuals. At the seedling period of stand development, the systematic environmental gradients had a dominant impact on the spatial patterns of dbh and total height; however, the impact of environmental gradients diminished as stands developed. Intertree competition was evident in the autocorrelation measures, i.e., Moran and Geary indices, which declined with increased density and with stand age. Moran index was statistically significant when competition was severe. Confounding of intertree competition and microsite variation effects made the spatial patterns of observation very complicated and difficult to describe mathematically. Autocorrelation was predominantly positive with total height, but mostly insignificant or negative with dbh in the juvenile period of loblolly pine stands, which suggests that total height is less sensitive to competition. For. Sci. 40(4):774-786.
The Use of Ordinal Response Methodology in Forestry
Authors: Schabenberger Oliver 
Published: April 2024

Abstract
Ordinal regression techniques are introduced as a means to achieve multiple data analytical goals such as data smoothing for subsequent model derivation and prediction of response distributions conditional on some measurable covariates. Their usefulness to address some pertinent problems in forest biometry are discussed. For. Sci. 41(2):321-336.
Evaluation of Competition Indices in Individual Tree Growth Models
Authors: Biging Gregory S. , Dobbertin Matthias 
Published: April 2024

Abstract
In this paper we explore how well distance-independent competition measures explain variation in the height and diameter squared growth of individual conifer trees. We investigated a number of stand-level density indices and individual tree competition indices which incorporate tree sizes, but do not include location. We model growth of individual trees as potential growth reduced by competition. The reduction in mean square error relative to no competition index was used to judge performance of each competition index which varies by species and growth component (height or diameter squared growth). Results are summarized by species and type of competition index. The distance-independent measures are also compared to selected distance-dependent measures shown in recent research work to perform well for conifer species. It was found that a new class of distance-independent indices that includes estimated crown parameters performs on par with the best distance-dependent competition indices when used in conjunction with models of individual tree height and diameter squared growth. For. Sci. 41(2):360-377.
Growth and Management of Mixed-Species, Uneven-Aged Forests in the French Jura: Implications for Economic Returns and Tree Diversity
Authors: Buongiorno Joseph , Peyron Jean-Luc , Houllier François , Bruciamacchie Max 
Published: April 2024

Abstract
The forests of the Jura mountains are among the most productive in France. This study developed quantitative models to improve the management of these mixed forests of fir, spruce, and beech. A nonlinear matrix model of stand growth was estimated and validated with medium-term projections and simulations of long-term stand dynamics. The ecological criteria were Shannon's index of tree diversity by species and size, the minimum number of trees in any species-size class, and basal area. The economic criteria were the present value of harvests, gross or net of the value of the growing stock, and the rate of return on the capital invested in the growing stock. Linear and goal programming were used to determine the effects, on all criteria, of managements that would maintain the stand in a steady state, and either (i) remove only the dead trees, (ii) maintain the forest close to its current state, (iii) achieve economic efficiency, subject to a desired level of diversity, (iv) maximize diversity, with or without constraints on economic returns. The results suggested that a light management could improve tree diversity, relative to natural stand growth. Maximum economic efficiency would require a substantial reduction in basal area and average size of trees, and it would lead to low tree diversity. Maximizing unconstrained tree diversity would be costly. Managements that conciliated diversity and economic efficiency all required a decrease in the basal area of stands, relative to their current state. A simple approach to convert a stand from its current condition to a desired steady state was investigated. For. Sci. 41(3):397-429.
No Long-Term Impact of Carbaryl Treatment on Western Spruce Budworm Populations and Host Trees in the Malheur National Forest, Oregon
Authors: Torgersen Torolf R. , Powell David C. , Hosman Kevin P. , Schmidt Fred H. 
Published: April 2024

Abstract
The effects of a single application of carbaryl on western spruce budworm (Choristoneura occidentalis Freeman) populations on the Malheur National Forest in northeastern Oregon were examined for 7 consecutive years beginning in 1983. Budworm control was evident only in the treatment year, 1983, and the next, 1984. There was little difference in the pattern of budworm population behavior between treated and untreated sites during the 7 yr study. Defoliation of Douglas-fir and true firs was reduced slightly by the carbaryl treatment, but did not translate into increased radial growth. On the contrary, there was a general decline in annual radial increment among host trees in both treated and untreated areas from 1980 to 1987, presumably because of chronic defoliation. For. Sci. 41(4):851-863.
A Multistage Stochastic Programming Model for Sustainable Forest-Level Timber Supply Under Risk of Fire
Authors: Boychuk Dennis , Martell David L. 
Published: April 2024

Abstract
Forest management planning models are highly developed and used extensively, but few explicitly consider the effects of fire and other uncertain losses which can be significant. Previous studies recommended contradictory responses to potential fire loss. We developed forest-level timber management optimization models with deterministic average and stochastic fire loss and used them to develop insight into the impact of uncertainty on forest management planning. Our analysis indicated that producing a stable timber supply requires the establishment of a buffer stock of timber. This strategy reduces the short-term harvest quantity, but increases the expected long-term harvest quantity. Paradoxically, the timber supply is both more stable, and larger. The results are sensitive to the method of regulating timber production: profit maximizing behavior of future producers requires a much greater buffer stock. In addition, bounds on the effect of transportation were developed, conditions where the mean value problem is adequate were identified, and the effect of a downward sloping demand curve was investigated. For. Sci. 42(1):10-26.
Forests, Agriculture, and Child Health in Zaire: A Household Modeling Approach
Authors: Larson Bruce A. , Barnes Grenville , Rogers Glenn , Larson Joy Green 
Published: April 2024

Abstract
In the Kwilu subregion of Zaire, where malnutrition rates are among the highest in rural Zaire, farm households depend directly on forested land for agricultural production and harvesting of nontimber forest products. A nonseparable model of an agricultural household, where production and consumption decisions are simultaneously determined, is developed in this paper based on several specific characteristics of the Kwilu. The model is used to examine the internal nonmarket and external market adjustments that rural households can make when forested land becomes less available to households because of, for example, population growth and deforestation. When forested land becomes less available, the specific conditions are identified where farmers (women) work harder for less return while allocating less time to child care activities. The end result is poorer child health. For. Sci. 42(1):3-9.
Implications of Modern Successional Theory for Habitat Typing: A Review
Authors: Cook James E. 
Published: April 2024

Abstract
The habitat type classification system (HTCS) is widely used in the western United States and has recently been applied in the Lake States. This classification system is based on three premises, two of which are embodied in the Clementsian theory of succession. These premises are (1) the climatic or potential climax is the same for all sites that have similar growing environments within a region, (2)the climax stage of succession reflects the inherent productivity of a site better than any other stage, and (3) after disturbance, the understory stabilizes more quickly than, and independent of, the overstory. The current understanding of succession, disturbance, and interactions between overstory and understory was reviewed and showed that the three premises on which HTCSs are based cannot be accepted a priori as widely applicable. In particular, it was concluded that (1) most sites will never support a climax stage (sensu Clements); (2) disturbances, past land use, and stochastic events can lead to multiple pathways on a single "type" of site; and (3) the overstory often exerts a significant effect on the understory. Thus, a land classification system that relies solely or heavily on vegetation, such as the HTCS, should be based on a new theoretical foundation and incorporate the known variation and stochasticity of vegetation dynamics. This means a new standard and additional analyses must be incorporated during the development of HTCS's so that the systems are more accurate, widely applicable and as useful as possible. For. Sci. 42(1):67-75.