Download or read book Construction of Regression Models for Predicting Crown Development in Southwestern Oregon Douglas fir written by Douglas Alan Maguire and published by . This book was released on 1986 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: A branch mortality dating technique and whorl sampling strategy were implemented to model five-year crown recession from data collected on temporary plots. Twenty-eight Douglas-fir from two levels-of-growing- stock studies in Oregon and Washington were first dissected to validate the proposed dating technique and assess alternative sampling strategies. Branch mortalities in 10-15 whorls below crown base were dated by locating discontinuities between branch and bole growth rings in stem cross-sections. Along with height measurements to the sample whorls, this technique allowed reconstruction of past crown base positions. Backdated heights to crown base corresponded closely with 15-year repeat crown measurements taken on the same trees. Seven sampling strategies (sampling scheme and estimator) were assessed for their ability to estimate past five-year crown recession by sampling only two to four whorls per tree. Simple linear regressions of estimated on actual recession for various five-year intervals suggested that a two-whorl sampling scheme with an appropriate estimator would perform adequately on temporary growth plots. This sampling strategy was applied to 357 Douglas-fir from temporary growth plots in southwestern Oregon. Numerous nonlinear and logarithmic models were developed to predict five-year crown recession from other tree, stand, and site variables. Residual analyses and indices of fit demonstrated that a multiplicative model with lognormal errors was the most appropriate model form. Sapwood taper above breast height was modeled with a quadratic-quadratic segmented polynomial. This taper function allowed extrapolation or interpolation of sapwood area measurements near crown base to sapwood area at crown base. Transformation of gross crown dimensions into expressions of conic surface area yielded accurate predictions of sapwood area at crown base. These expressions were therefore inferred to reflect equally well the total leaf area of individual Douglas-fir trees in southwestern Oregon. Modeling at the resolution of gross crown dimensions therefore possesses both the physiological appeal of providing an accurate index of the tree's relative photosynthetic capacity and the conceptual appeal of portraying competition for light and aerial growing space.

Download or read book Research Paper Forest Research Laboratory Oregon State University written by Oregon State University. Forest Research Laboratory and published by . This book was released on 1979 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canadian Journal of Forest Research written by and published by . This book was released on 2008 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Equations for Predicting the Largest Crown Width of Stand grown Trees in Western Oregon written by David W. Hann and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Largest crown width (LCW) equations for stand-grown trees were developed for 14 tree species found in western Oregon. The equations are used in the growth-and-yield model ORGANON and in the stand-visualization program VIZ4ST. They were constructed such that LCW equals the maximum crown width of open-grown trees when the crown ratio is equal to one. Tree measurements needed for the equations are diameter at breast height (in.), total tree height (ft), and crown length (ft).

Download or read book Predicting Crown Weight of Coast Douglas fir and Western Hemlock written by J. A. Kendall Snell and published by . This book was released on 1981 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Crown Profile of Douglas fir in the Western Willamette Valley written by Joseph T. Mortzheim and published by . This book was released on 1996 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crown profile was modeled using a system of equations with three components. The first equation predicts the maximum crown width of an open grown tree based on the tree's diameter at breast height. The second equation modifies maximum crown width to represent the largest width of the crown in stand grown trees. The third component of the system is a group of equations which model the relative position of a stand grown tree's largest crown width and modify the largest width of the crown to represent the width of the crown at all heights throughout the crown. Existing maximum crown width equations were scaled to match the geographic region of the Western Willamette Valley. Independent datasets and non-linear regression techniques were used to fit the remaining models. Equations for modeling crown widths at heights at and above the height of the largest crown width were highly predictive. Unfortunately, equations for modeling crown widths at lower heights than the largest crown width were considerably less accurate. Verification of the overall system indicated the presence of a small amount of bias, but the system produced a high level of accuracy even when the bias was included in predictions. Signature redacted for privacy.

Download or read book Forestry Theses Accepted by Colleges and Universities in the United States written by and published by . This book was released on 1981 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1973 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Forestry Theses Accepted by Colleges and Universities in the United States July 1981 June 1990 written by and published by . This book was released on 1994 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Enhanced Height growth rate Equations for Undamaged and Damaged Trees in Southwest Oregon written by David W. Hann and published by . This book was released on 2002 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equations for predicting the 5-yr height growth rate of a tree are presented for six conifer species from southwest Oregon. Equations for the combination of undamaged and damaged trees were estimated with weighted nonlinear regression techniques. These equations are being incorporated into the new southwest Oregon version of ORGANON, a model for predicting the development of stands. The equations extend the previous model to older stands and to stands with a heavier component of hardwood tree species. The effects of specific damaging agents on the 5-yr height growth rate were explored for Douglas-fir, the most frequently encountered species, and damage correction factors were estimated. The findings of this analysis indicated that damaging agents can have a significant impact upon 5-yr height growth rate, and as a result, they can lead, over time, to diversification in within-stand structure. Therefore, a full characterization of stand development should include the prediction of the presence and frequency of the various damaging agents affecting trees within the stand and their subsequent impact upon tree attributes such as total height, height to crown base, diameter growth rate, height growth rate, and mortality rate.

Download or read book Diameter Growth Equations for Douglas fir and Grand Fir in the Western Willamette Valley of Oregon written by Abdel Azim Zumrawi and published by . This book was released on 1993 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Equations for predicting diameter growth are an essential component of single-tree growth and yield models (Munro 1974). Diameter growth predictions are used to characterize individual-tree development and to project the growth of stand basal area and volume. Both diameter growth and basal area growth have been used as the dependent variable in modeling the development of a tree's diameter (Holdaway 1984, Ritchie and Hann 1985, Wykoff 1986, Wensel et al. 1987, Dolph 1988). The choice of which dependent variable to use has usually been suggested by the data, including the behavior of the residuals and the goodness-of-fit of the resulting equations. Ritchie and Hann (1985) developed nonlinear basal-area growth equations for Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis). It was intended that the equations would be used to predict individual- tree diameter growth in the western Willamette Valley version of ORGANON (Hann et al. 1992). However, Hann and Larsen (1991) found that using a basal-area growth equation to predict diameter growth could result in erratic and unreasonable predictions of diameter growth for trees with small diameters. Therefore, the objective of the present study was to develop diameter growth equations for Douglas-fir and grand fir in the western Willamette Valley of Oregon by using the equation form of Hann and Larsen (1991)."--Introduction.

Download or read book Forest Pruning Bibliography written by Kevin Laughlin O'Hara and published by . This book was released on 1989 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiple Regression Inference of Yield for Douglas fir Plantations in the Pacific Northwest written by Nai Kuang Saetern and published by . This book was released on 2012 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple regressions were formulated with predictor variables of latitude, longitude, and elevation, stand stocking, age, and site index for western Oregon, western Washington, and southwest British Columbia. Models were assessed for normality using plots of studentized residuals by fitted values, q-q plots, and fit was assessed by R2 value. Outliers were examined based upon Bonferroni p-values and Cook's distance. The developed seven multiple regression models were for response variables of cubic foot volume including top, cubic foot volume to top 4 and 6 inches in diameter, and Scribner board foot volume to top 4 and 6 inches in diameter. These models were used to examine the effects of early density controls and the effects of subsequent heavy first thinnings on volume yield. The assessment concluded that early density controls resulted in highest to lowest productivity in the order of 100 initial Trees Per Acre (TPA), 300 TPA, 500 TPA, and 700 TPA. In assessing effects from a first thin, the 300 TPA class was shown to have the most increased volume. The first thinning in the 500 and 700 TPA levels showed an overall minimal increase in volume and diameter size due to a longer delay in allocating growth from the crown to the stem. The models produced in this study can be of use in assessing and understanding predictions made by other regional growth models.

Download or read book Estimating the Weight of Crown Segments for Old Growth Douglas Fir and Western Hemlock Classic Reprint written by J. A. Kendall Snell and published by Forgotten Books. This book was released on 2017-11-19 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Estimating the Weight of Crown Segments for Old-Growth Douglas-Fir and Western Hemlock Equations were developed for predicting weight of continuous live crown, total live crown, dead crown, any segment of live crown, and individual branches for old-growth Douglas-fir (pseudotsuga menziesii (mirb.) Franco) and western hem lock (tsuga heterophylla (raf.) Sarg.) trees. A branch method and a ratio method were developed for estimating the weight of crown segments. Equations were based on data from 32 Douglas-fir and 29 western hemlock trees from the Gifford Pinchot National Forest in southwestern Washington. An additional 49 Douglas-fir and 50 western hemlock were selected for validating the models. For predicting weight of a segment of crown, the branch method was less biased and more accurate than the ratio method. The branch method is recommended for felled trees because it more easily accommodates the large amount of break age ln the crown of felled old - growth trees. Keywords: Crown weights, estimates, moisture content (wood), old-growth stands, Douglas-fir, western hemlock. The purpose of this study was to develop and validate estimators to predict total crown weight and weight of any segment of crown for old-growth felled and bucked Douglas-fir and western hemlock trees. Equations were developed for pre dicting weight of continuous live crown, total live crown, dead crown, any seg ment of live crown, and individual branches. A branch method and ratio method were developed for estimating the weight of crown segments. Equations were based on data from 32 Douglas-fir and 29 western hemlock trees from the Gifford Pinchot National Forest in southwestern Washington. An additional 49 Douglas-fir and 50 western hemlock were selected for validating the models. For predicting weight of a segment of crown, the branch method was less biased and more accurate than the ratio method. The branch method is recommended for felled trees because it more easily accommodates the large amount of break age in the crown of felled old-growth trees. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1985 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Models of Height Growth for Douglas fir in Southwestern Oregon written by John Scrivani and published by . This book was released on 1985 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review is made of methods which assess the bias and non-normality of parameter estimates and predictions obtained with nonlinear regression. Particular emphasis is placed upon curvature measures of nonlinearity, related measures of parameter and prediction bias, and the effects of reparameterizations. Alternate models of individual tree height growth are compared on the basis of mean square error, intrinsic nonlinearity, parameter effects nonlinearity, and estimated bias. While results are specific to the data examined, some general conclusions are made concerning appropriate models for individual tree height growth. Both the Richards and a Weibull-type growth model are found to adequately describe individual tree height growth, with low levels of intrinsic nonlinearity, and acceptable parameter effects nonlinearity following repararneterization. Some evidence is found for a modification of either the Richards or Weibull model to include an asymptotic linear growth rate when modeling the height growth of some western conifers past the age of 200. Stem analysis data on Douglas-fir height growth in mixed confier stands located in southwestern Oregon are used to develop a system of dominant height growth and site index prediction. The Weibull model is used successfully to develop a polymorphic height growth prediction equation. A linear model, estimated with site index as the dependent variable, is used to predict site index. A comparision is made of pooled least squares and random coefficient estimation methods. The random coefficient method is found to more closely model the shape of early height growth, but appears to result in more biased predictions and performs very poorly on older height growth, with both the estimation and validation data. Alternative error assumptions are examined with the pooled data method. The best performance in validation is obtained with assumption of independent errors, heteroscedastic across trees.

Download or read book Development of a Hybrid Modeling Framework for Intensively Managed Douglas fir Plantations in the Pacific Northwest written by Aaron R. Weiskittel and published by . This book was released on 2007 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annualized empirical equations for individual tree diameter and height growth were developed next and found to outperform similar models with a longer time-step. The parameters of these empirical equations showed very few meaningful relationships with physiography, soil, or climate, suggesting that representation of key physiological processes was a necessary next step.