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James C. Finley - One of the best experts on this subject based on the ideXlab platform.
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aggregate height a composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
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Aggregate height—A composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
Songlin Fei - One of the best experts on this subject based on the ideXlab platform.
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aggregate height a composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
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Aggregate height—A composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
Kim C. Steiner - One of the best experts on this subject based on the ideXlab platform.
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aggregate height a composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
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Aggregate height—A composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
Peter Gould - One of the best experts on this subject based on the ideXlab platform.
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aggregate height a composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
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Aggregate height—A composite measure of Stand Density for tree seedling populations
Forest Ecology and Management, 2006Co-Authors: Songlin Fei, Peter Gould, Kim C. Steiner, James C. FinleyAbstract:Abstract Aggregate height, a composite measure of seedling size and number per unit area, is proposed for describing Stand Density of seedling populations during early Stand development. Aggregate height is analogous to other Stand Density measurements, such as basal area, that incorporate both size and number of trees into a single value. A large scale dataset (3452 subplots in 33 Stands) from the central Appalachians and a long-term dataset (six Stands from pre- to 20-years post-harvest) from the Missouri Ozarks were used to compare the utility of number of seedlings, mean height, aggregate height squared, and aggregate height for examining patterns of Stand development. Comparisons of coefficients of determination ( r 2 ) indicate that aggregate height produces more deterministic models for describing the early development of tree seedling populations than do number of seedlings, mean height, and aggregate height squared. Stand developmental paths based on number of seedlings, basal area, and aggregate height reveal that the onset of the self-thinning stage coincides with the shifting of mean Stand aggregate height, but not other measurements. The results indicate that aggregate height is an efficient measure of Stand Density to describe the relative prevalence of a species at a given stage of development and its ability to persist into future stages.
Mark J. Ducey - One of the best experts on this subject based on the ideXlab platform.
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A Stand Density index for complex mixed species forests in the northeastern United States
Forest Ecology and Management, 2010Co-Authors: Mark J. Ducey, Rachel A. KnappAbstract:Quantifying Stand Density is important for accurate prediction of net biomass and carbon accumulation, for estimating growth and mortality risks of trees, Stands, and regions, and for the management of forests for multiple goods and services. Building on previous work relating maximum Stand Density to wood specific gravity, we develop a Stand Density equation for the mixed species forests of the northeastern United States using data from the US Forest Service, Forest Inventory and Analysis program. We used quantile regression, in concert with a quantile selection and evaluation procedure, to ensure conformity between our Density measure and previously developed guidance for well-studied Stand types. The resulting strictly additive relative Density measure appears to provide reasonable prediction of maximum Density even for plantations of exotic conifers in the region. The results suggest that maximum Stand densities after accounting for wood specific gravity may be lower in northeastern North America than in the south or west.
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Direct Sampling for Stand Density Index
Western Journal of Applied Forestry, 2008Co-Authors: Mark J. Ducey, Harry T. ValentineAbstract:A direct method of estimating Stand Density index in the field, without complex calculations, would be useful in a variety of silvicultural situations. We present just such a method. The approach uses an ordinary prism or other angle gauge, but it involves deliberately “pushing the point” or, in some cases, “pulling the point.” This adjusts the usual limiting distances in prism sampling to match the limiting distances required for sampling with a specified Stand Density factor (SDF). The estimate of Stand Density associated with a point is just the number of trees tallied times the SDF; no diameter measurements are needed. We give guidelines on choosing an SDF on the basis of expected Stand characteristics and equations for calculating the limiting distances and the amount of “push.” Field implementation of the resulting method is extremely fast and simple.
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Is there a correct Stand Density index? An alternate interpretation.
Western Journal of Applied Forestry, 2003Co-Authors: Mark J. Ducey, Bruce C. LarsonAbstract:Abstract Recent authors have asserted that the original form of Reineke's Stand Density index is flawed, and that an additive version represents the correct form. An examination of the literature provides no historical or mathematical reason why additivity should be required in the original index. Reineke's Stand Density index, and the additive or area-based Stand Density index, should be considered as separate indices with different properties. The sensitivity of the area-based index to Stand diameter distribution is illustrated with the Weibull distribution. Its sensitivity provides testable hypotheses that could be used in empirical studies to determine the better index. West. J. Appl. For. 18(3):179–184.
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Rapid Assessment of Risk Using Stand Density Indices.
Western Journal of Applied Forestry, 1999Co-Authors: Mark J. Ducey, Bruce C. LarsonAbstract:Abstract When management decisions are based on a Stand Density measure, there is always a risk that sampling error will result in an incorrect management choice. Estimating confidence limits and associated probabilities for many popular Stand Density measures is computationally difficult, and can require information that is difficult to obtain in practice. Here, we present an alternative method for rapid assessment of risk that is applicable to Reineke's Stand Density index, Wilson's relative spacing, Drew and Fiewelling's relative Density index, and Curtis's relative Density. The method requires an independent estimate of Stand Density, for example, from a growth and yield model or from a subjective assessment before actual measurement. The results, while inexact, are both easier to obtain and more conservative than those obtained by exact methods. West. J. Appl. For. 14(3):149-152.
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Thinning decisions using Stand Density indices: The influence of uncertainty.
Western Journal of Applied Forestry, 1997Co-Authors: Mark J. Ducey, Bruce C. LarsonAbstract:Abstract In practice, Stand Density indices must be estimated from sample data, leading to uncertainty in both estimates of Stand Density and resulting thinning decisions. We provide a statistical framework for thinning decisions based on Density thresholds. We show how to assess the adequacy of existing cruise data to guide the thinning process, and to design more cost-effective sampling plans. We present this information in a series of graphs which, when used in conjunction with Density management diagrams, can improve rational thinning decisions. West. J. Appl. For. 12(3):89-92.
