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• 11. [Article] Diameter growth equations for fourteen tree species in Southwest Oregon

  Equations are presented that predict individual-tree 5-year diameter growth, outside bark, for 14 tree species in southwest Oregon. The data used to develop the equations came from 19,245 trees sampled ...

  Citation × Citation Citation Abstract Copy Title: Diameter growth equations for fourteen tree species in Southwest Oregon Author: Larsen, David R., Oregon State University. Forest Research Laboratory, Hann, David W. Equations are presented that predict individual-tree 5-year diameter growth, outside bark, for 14 tree species in southwest Oregon. The data used to develop the equations came from 19,245 trees sampled from 391 stands in the study area. These equations express diameter growth as a function of diameter at breast height, crown ratio, site index, total stand basal area, and stand basal area in trees with diameters larger than the subject tree's diameter. The parameters of the equations were estimated by using weighted, nonlinear regression. Title: Diameter growth equations for fourteen tree species in Southwest Oregon Author: Larsen, David R., Oregon State University. Forest Research Laboratory, Hann, David W. Equations are presented that predict individual-tree 5-year diameter growth, outside bark, for 14 tree species in southwest Oregon. The data used to develop the equations came from 19,245 trees sampled from 391 stands in the study area. These equations express diameter growth as a function of diameter at breast height, crown ratio, site index, total stand basal area, and stand basal area in trees with diameters larger than the subject tree's diameter. The parameters of the equations were estimated by using weighted, nonlinear regression. Close

• 12. [Article] Equations for predicting the 5-year height growth of six conifer species in southwest Oregon

  Equations for predicting individual-tree height growth per 5-year period are presented for Douglas-fir, white fir, grand fir, ponderosa pine, sugar pine, and incense-cedar growing in the mixed-conifer ...

  Citation × Citation Citation Abstract Copy Title: Equations for predicting the 5-year height growth of six conifer species in southwest Oregon Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Equations for predicting individual-tree height growth per 5-year period are presented for Douglas-fir, white fir, grand fir, ponderosa pine, sugar pine, and incense-cedar growing in the mixed-conifer zone of southwest Oregon. The data used to develop the equations came from 3,648 trees sampled from 391 stands in the study area. Parameters were estimated by means of nonlinear regression. The model for height growth is expressed as a function of site index, total tree height, crown ratio, and percentage of crown closure at total height of the subject tree. Title: Equations for predicting the 5-year height growth of six conifer species in southwest Oregon Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Equations for predicting individual-tree height growth per 5-year period are presented for Douglas-fir, white fir, grand fir, ponderosa pine, sugar pine, and incense-cedar growing in the mixed-conifer zone of southwest Oregon. The data used to develop the equations came from 3,648 trees sampled from 391 stands in the study area. Parameters were estimated by means of nonlinear regression. The model for height growth is expressed as a function of site index, total tree height, crown ratio, and percentage of crown closure at total height of the subject tree. Close

• 13. [Article] Equations for predicting the height to crown base of six tree species in the central western Willamette Valley of Oregon

  This paper presents equations developed to predict the height to live crown base of six species in the central western Willamette Valley of Oregon. Weighted nonlinear regression was used to fit a separate ...

  Citation × Citation Citation Abstract Copy Title: Equations for predicting the height to crown base of six tree species in the central western Willamette Valley of Oregon Author: Zumrawi, Abdel Azim M. A., Oregon State University. Forest Research Laboratory, Hann, David W. This paper presents equations developed to predict the height to live crown base of six species in the central western Willamette Valley of Oregon. Weighted nonlinear regression was used to fit a separate logistic equation for each species. The predictor variables are total tree height, crown competition factor in trees with larger diameter at breast height than the subject tree, stand basal area, and diameter-height ratio. The equations will be used in two ways: 1) to estimate crown ratio on trees for which that measurement is missing, and 2) to simulate crown change in a single-tree/distance-independent growth and yield model. Application of these equations will be most reliable in stands that are free from thinning effect. Title: Equations for predicting the height to crown base of six tree species in the central western Willamette Valley of Oregon Author: Zumrawi, Abdel Azim M. A., Oregon State University. Forest Research Laboratory, Hann, David W. This paper presents equations developed to predict the height to live crown base of six species in the central western Willamette Valley of Oregon. Weighted nonlinear regression was used to fit a separate logistic equation for each species. The predictor variables are total tree height, crown competition factor in trees with larger diameter at breast height than the subject tree, stand basal area, and diameter-height ratio. The equations will be used in two ways: 1) to estimate crown ratio on trees for which that measurement is missing, and 2) to simulate crown change in a single-tree/distance-independent growth and yield model. Application of these equations will be most reliable in stands that are free from thinning effect. Close

• 14. [Article] Nonlinear equations for predicting diameter and squared diameter inside bark at breast height for Douglas-fir

  Citation × Citation Citation Abstract Copy Title: Nonlinear equations for predicting diameter and squared diameter inside bark at breast height for Douglas-fir Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Title: Nonlinear equations for predicting diameter and squared diameter inside bark at breast height for Douglas-fir Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Close

• 15. [Article] Predicting height for undamaged and damaged trees in southwest Oregon

  Equations for predicting tree height as a function of diameter outside bark at breast height are presented for various tree species common to southwest Oregon. Data for damaged and undamaged trees were ...

  Citation × Citation Citation Abstract Copy Title: Predicting height for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Equations for predicting tree height as a function of diameter outside bark at breast height are presented for various tree species common to southwest Oregon. Data for damaged and undamaged trees were analyzed with weighted nonlinear regression techniques. The effects of specific damaging agents and their severity on the height-diameter relationship were explored. Damage correction multipliers were estimated, then used to correct predicted height where damage was noted. Because the relationship between height and diameter changes with the competitive position of the tree in a stand, alternative equations are presented that include the average height and diameter of the 40 largest-diameter undamaged conifer trees per acre. Foresters can use these "height-diameter" equations to reduce the time-consuming task of measuring heights of every tree in an inventory, stand exam, or timber cruise. They can also use these equations to estimate the change in height as diameter changes. These equations will be incorporated into the new southwest Oregon version of ORGANON, which extends the model to older stands and stands with a heavier component of hardwood species. Title: Predicting height for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Equations for predicting tree height as a function of diameter outside bark at breast height are presented for various tree species common to southwest Oregon. Data for damaged and undamaged trees were analyzed with weighted nonlinear regression techniques. The effects of specific damaging agents and their severity on the height-diameter relationship were explored. Damage correction multipliers were estimated, then used to correct predicted height where damage was noted. Because the relationship between height and diameter changes with the competitive position of the tree in a stand, alternative equations are presented that include the average height and diameter of the 40 largest-diameter undamaged conifer trees per acre. Foresters can use these "height-diameter" equations to reduce the time-consuming task of measuring heights of every tree in an inventory, stand exam, or timber cruise. They can also use these equations to estimate the change in height as diameter changes. These equations will be incorporated into the new southwest Oregon version of ORGANON, which extends the model to older stands and stands with a heavier component of hardwood species. Close

• 16. [Article] Enhanced height-growth-rate equations for undamaged and damaged trees in southwest Oregon

  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 ...

  Citation × Citation Citation Abstract Copy Title: Enhanced height-growth-rate equations for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W. 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. Title: Enhanced height-growth-rate equations for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W. 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. Close

• 17. [Article] Extending southwest Oregon's Douglas-fir dominant height growth equation to older ages

  Hann and Scrivani (1987) developed dominant height growth equations for Douglas- fir in southwest Oregon using stem analysis data sets with an upper age of approximately 125 years at breast height. The ...

  Citation × Citation Citation Abstract Copy Title: Extending southwest Oregon's Douglas-fir dominant height growth equation to older ages Author: Oregon State University. Forest Research Laboratory, Hann, David W. Hann and Scrivani (1987) developed dominant height growth equations for Douglas- fir in southwest Oregon using stem analysis data sets with an upper age of approximately 125 years at breast height. The objective of this study was to determine whether these equations could be extrapolated for ages of 250 years or more. Data for the evaluation came from stem analysis of 60 dominant trees located in 30 "older" stands. Intensive data screening indicated that 53 of these trees exhibited signs of reduced height growth during their first 100 years of development due to competition from non-tree vegetation, hardwood tree species, and possibly other conifers in non-even-aged stands. Analysis of the remaining seven site-quality trees indicated that the existing dominant height growth equation for Douglas-fir could be extrapolated to breast height ages of up to 245 years without loss of accuracy or precision. Title: Extending southwest Oregon's Douglas-fir dominant height growth equation to older ages Author: Oregon State University. Forest Research Laboratory, Hann, David W. Hann and Scrivani (1987) developed dominant height growth equations for Douglas- fir in southwest Oregon using stem analysis data sets with an upper age of approximately 125 years at breast height. The objective of this study was to determine whether these equations could be extrapolated for ages of 250 years or more. Data for the evaluation came from stem analysis of 60 dominant trees located in 30 "older" stands. Intensive data screening indicated that 53 of these trees exhibited signs of reduced height growth during their first 100 years of development due to competition from non-tree vegetation, hardwood tree species, and possibly other conifers in non-even-aged stands. Analysis of the remaining seven site-quality trees indicated that the existing dominant height growth equation for Douglas-fir could be extrapolated to breast height ages of up to 245 years without loss of accuracy or precision. Close

• 18. [Article] Predicting height to crown base for undamaged and damaged trees in southwest Oregon

  Equations for predicting height to crown base are presented for tree species from southwest Oregon. Equations for undamaged and damaged trees were estimated with weighted nonlinear regression techniques. ...

  Citation × Citation Citation Abstract Copy Title: Predicting height to crown base for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Equations for predicting height to crown base are presented for tree species from southwest Oregon. Equations for undamaged and damaged trees were estimated with weighted nonlinear regression techniques. The effects of specific damaging agents on the height to crown base were explored, and damage correction factors were estimated. The damage correction factors can be used to correct the predicted crown ratio for specific damaging agents and their severity in samples where damage is noted. These equations are being incorporated into the new southwest Oregon version of ORGANON (ORegon Growth ANalysis and projectiON), a model for predicting the growth of individual trees in forest stands. The equations extend the past model to older stands and stands with a heavier component of hardwood tree species. Title: Predicting height to crown base for undamaged and damaged trees in southwest Oregon Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Equations for predicting height to crown base are presented for tree species from southwest Oregon. Equations for undamaged and damaged trees were estimated with weighted nonlinear regression techniques. The effects of specific damaging agents on the height to crown base were explored, and damage correction factors were estimated. The damage correction factors can be used to correct the predicted crown ratio for specific damaging agents and their severity in samples where damage is noted. These equations are being incorporated into the new southwest Oregon version of ORGANON (ORegon Growth ANalysis and projectiON), a model for predicting the growth of individual trees in forest stands. The equations extend the past model to older stands and stands with a heavier component of hardwood tree species. Close

• 19. [Article] Equations for predicting height to crown base for fourteen tree species in southwest Oregon

  Equations are presented for predicting height to crown base (or bole ratio) for fourteen species of trees common to the mixed-conifer zone of southwest Oregon. Nonlinear regression was used to fit a weighted ...

  Citation × Citation Citation Abstract Copy Title: Equations for predicting height to crown base for fourteen tree species in southwest Oregon Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Equations are presented for predicting height to crown base (or bole ratio) for fourteen species of trees common to the mixed-conifer zone of southwest Oregon. Nonlinear regression was used to fit a weighted logistic function for each species. The independent variables include height, crown competition factor in larger trees, stand basal area, site index, and diameter divided by height. Although a number of alternative model forms were considered, the logistic function was found to fit the data best. Validation of the model indicated possible difficulties with ponderosa pine and golden chinkapin, but these problems are probably due to inconsistencies in the validation data rather than shortcomings in the individual models. Title: Equations for predicting height to crown base for fourteen tree species in southwest Oregon Author: Ritchie, Martin W., Oregon State University. Forest Research Laboratory, Hann, David W. Equations are presented for predicting height to crown base (or bole ratio) for fourteen species of trees common to the mixed-conifer zone of southwest Oregon. Nonlinear regression was used to fit a weighted logistic function for each species. The independent variables include height, crown competition factor in larger trees, stand basal area, site index, and diameter divided by height. Although a number of alternative model forms were considered, the logistic function was found to fit the data best. Validation of the model indicated possible difficulties with ponderosa pine and golden chinkapin, but these problems are probably due to inconsistencies in the validation data rather than shortcomings in the individual models. Close

• 20. [Article] Height-diameter equations for six species in the coastal regions of the Pacific Northwest

  Three equations for predicting tree height as a function of diameter (outside bark) at breast height are presented for six species found in coastal regions of the Pacific Northwest. Foresters can use these ...

  Citation × Citation Citation Abstract Copy Title: Height-diameter equations for six species in the coastal regions of the Pacific Northwest Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Three equations for predicting tree height as a function of diameter (outside bark) at breast height are presented for six species found in coastal regions of the Pacific Northwest. Foresters can use these "height–diameter" equations to avoid the time-consuming task of measuring heights of all individual trees in an inventory, a stand exam, or a timber cruise. Equation coefficients were estimated with weighted nonlinear regression techniques. Because the relationship between a tree's height and diameter depends on the tree's competitive position within the stand, alternative equations, including the average height and average diameter of the 40 largest-diameter trees/ac, are also presented. These equations are used in the Stand Management Cooperative version of ORGANON. Title: Height-diameter equations for six species in the coastal regions of the Pacific Northwest Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Three equations for predicting tree height as a function of diameter (outside bark) at breast height are presented for six species found in coastal regions of the Pacific Northwest. Foresters can use these "height–diameter" equations to avoid the time-consuming task of measuring heights of all individual trees in an inventory, a stand exam, or a timber cruise. Equation coefficients were estimated with weighted nonlinear regression techniques. Because the relationship between a tree's height and diameter depends on the tree's competitive position within the stand, alternative equations, including the average height and average diameter of the 40 largest-diameter trees/ac, are also presented. These equations are used in the Stand Management Cooperative version of ORGANON. Close