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• 1. [Article] Estimation and analysis of costs for developed recreation sites in U.S. Forest Service Region One

  An economic cost analysis of 258 Forest Service developed recreation sites in Region One examined eleven different site types, including campgrounds, picnic grounds, boating and swimming sites, interpretive ...

  Citation × Citation Citation Abstract Copy Title: Estimation and analysis of costs for developed recreation sites in U.S. Forest Service Region One Author: Gibbs, Kenneth C., Oregon State University. Forest Research Laboratory, Reed, Frederick L. An economic cost analysis of 258 Forest Service developed recreation sites in Region One examined eleven different site types, including campgrounds, picnic grounds, boating and swimming sites, interpretive sites, and information sites. Costs were estimated for planning, facilities, and operation and maintenance. Averaging costs by category showed that, in general, family campgrounds were less expensive than other site types per annum or per unit of capacity or use. Cost functions, estimated to predict the effect of size and use, should aid budgetary decisions and help planners better predict costs of existing sites and new developments. Title: Estimation and analysis of costs for developed recreation sites in U.S. Forest Service Region One Author: Gibbs, Kenneth C., Oregon State University. Forest Research Laboratory, Reed, Frederick L. An economic cost analysis of 258 Forest Service developed recreation sites in Region One examined eleven different site types, including campgrounds, picnic grounds, boating and swimming sites, interpretive sites, and information sites. Costs were estimated for planning, facilities, and operation and maintenance. Averaging costs by category showed that, in general, family campgrounds were less expensive than other site types per annum or per unit of capacity or use. Cost functions, estimated to predict the effect of size and use, should aid budgetary decisions and help planners better predict costs of existing sites and new developments. Close

• 2. [Article] Diameter growth equations for Douglas-fir and grand fir in the western Willamette Valley of Oregon

  "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 ...

  Citation × Citation Citation Abstract Copy Title: Diameter growth equations for Douglas-fir and grand fir in the western Willamette Valley of Oregon Author: Zumrawi, Abdel Azim, Oregon State University. Forest Research Laboratory, Hann, David W. "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 Title: Diameter growth equations for Douglas-fir and grand fir in the western Willamette Valley of Oregon Author: Zumrawi, Abdel Azim, Oregon State University. Forest Research Laboratory, Hann, David W. "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 Close

• 3. [Article] Tarif tables for mountain hemlock developed from an equation of total stem cubic-foot volume

  Tarif access tables were developed for mountain hemlock [Tsuga mertensiana (Bong.) Carr.] on the Deschutes National Forest in the Central Oregon Cascade Mountains from an equation for cubic-foot volume ...

  Citation × Citation Citation Abstract Copy Title: Tarif tables for mountain hemlock developed from an equation of total stem cubic-foot volume Author: Johnson, Gregory P., Bell, John F., Oregon State University. Forest Research Laboratory, Marshall, David D. Tarif access tables were developed for mountain hemlock [Tsuga mertensiana (Bong.) Carr.] on the Deschutes National Forest in the Central Oregon Cascade Mountains from an equation for cubic-foot volume including top and stump (CVTS). These tables provide access to the comprehensive tree-volume tarif system. Title: Tarif tables for mountain hemlock developed from an equation of total stem cubic-foot volume Author: Johnson, Gregory P., Bell, John F., Oregon State University. Forest Research Laboratory, Marshall, David D. Tarif access tables were developed for mountain hemlock [Tsuga mertensiana (Bong.) Carr.] on the Deschutes National Forest in the Central Oregon Cascade Mountains from an equation for cubic-foot volume including top and stump (CVTS). These tables provide access to the comprehensive tree-volume tarif system. Close

• 4. [Article] Metal-plate-connected wood joints : a literature review

  "This publication has presented an overview of current research on MPC joints in wood trusses. The literature search was primarily of U.S. sources, with some effort to obtain literature from other parts ...

  Citation × Citation Citation Abstract Copy Title: Metal-plate-connected wood joints : a literature review Author: Oregon State University. Forest Research Laboratory, Gupta, Rakesh, Vatovec, Milan, Miller, Thomas H. "This publication has presented an overview of current research on MPC joints in wood trusses. The literature search was primarily of U.S. sources, with some effort to obtain literature from other parts of the world. An enormous amount of important information has been amassed by studies on testing procedures and theoretical models. Among the many attributes that must be considered in modeling and analysis of joints and trusses are the effect of load angle, wood-plate orientation, size, thickness, stiffness of steel plates, and specific gravity of wood on the strength of the joints, as well as the effect of the gap closure between members, tooth damage or length, and tooth layout on the overall joint performance. Extensive research has been done on tension joints in trusses; some has been done on heel connections, but very little has been done on web and other connections. Researchers have devoted considerable effort to understanding tensile joints under axial loading. However, experience suggests that even tensile joints are subjected to combined loadings because of eccentricities. The behavior of a simple MPC joint is very complex and influenced by many variables, including plate properties, joint geometry, and the natural variability of wood. An integrated approach, as used by Foschi (1977), that considers the material behavior and interactions of wood and plate and that is simple but sufficiently accurate for designing joints should be developed. A standard method for studying the long-term behavior of MPC joints should be developed and used in design. One possible option would be to use a time-temperature superposition principle for developing long-term data from relatively short-term tests. Failure modes of the truss joints should be characterized. Work on dynamic behavior and environmental effects on the joints is also needed."--Summary and conclusions. Title: Metal-plate-connected wood joints : a literature review Author: Oregon State University. Forest Research Laboratory, Gupta, Rakesh, Vatovec, Milan, Miller, Thomas H. "This publication has presented an overview of current research on MPC joints in wood trusses. The literature search was primarily of U.S. sources, with some effort to obtain literature from other parts of the world. An enormous amount of important information has been amassed by studies on testing procedures and theoretical models. Among the many attributes that must be considered in modeling and analysis of joints and trusses are the effect of load angle, wood-plate orientation, size, thickness, stiffness of steel plates, and specific gravity of wood on the strength of the joints, as well as the effect of the gap closure between members, tooth damage or length, and tooth layout on the overall joint performance. Extensive research has been done on tension joints in trusses; some has been done on heel connections, but very little has been done on web and other connections. Researchers have devoted considerable effort to understanding tensile joints under axial loading. However, experience suggests that even tensile joints are subjected to combined loadings because of eccentricities. The behavior of a simple MPC joint is very complex and influenced by many variables, including plate properties, joint geometry, and the natural variability of wood. An integrated approach, as used by Foschi (1977), that considers the material behavior and interactions of wood and plate and that is simple but sufficiently accurate for designing joints should be developed. A standard method for studying the long-term behavior of MPC joints should be developed and used in design. One possible option would be to use a time-temperature superposition principle for developing long-term data from relatively short-term tests. Failure modes of the truss joints should be characterized. Work on dynamic behavior and environmental effects on the joints is also needed."--Summary and conclusions. Close

• 5. [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

• 6. [Article] Density management guide for red alder

  "Our diagram is intended to provide general guidance in density management of red alder. The management zone defines a reasonable compromise between individual-tree and stand growth and mortality. Factors ...

  Citation × Citation Citation Abstract Copy Title: Density management guide for red alder Author: Hibbs, David E., Puettmann, Klaus J., DeBell, Dean S., Oregon State University. Forest Research Laboratory "Our diagram is intended to provide general guidance in density management of red alder. The management zone defines a reasonable compromise between individual-tree and stand growth and mortality. Factors considered in its formation include desired tree size at harvest, growth rate, and yield per acre. Social and legal constraints, as well as wildlife habitat and other non-timber-related considerations, may affect how the guide is applied in developing a management plan. It must be remembered, however, that the density management diagram is only a statistical construct and does not account for events and processes that are not density-related. Developing complete management plans requires that these other factors also be considered. D.E. Hibbs and D.S. DeBell are now preparing a review of the various factors to be considered throughout a full rotation of red alder."--Conclusion Title: Density management guide for red alder Author: Hibbs, David E., Puettmann, Klaus J., DeBell, Dean S., Oregon State University. Forest Research Laboratory "Our diagram is intended to provide general guidance in density management of red alder. The management zone defines a reasonable compromise between individual-tree and stand growth and mortality. Factors considered in its formation include desired tree size at harvest, growth rate, and yield per acre. Social and legal constraints, as well as wildlife habitat and other non-timber-related considerations, may affect how the guide is applied in developing a management plan. It must be remembered, however, that the density management diagram is only a statistical construct and does not account for events and processes that are not density-related. Developing complete management plans requires that these other factors also be considered. D.E. Hibbs and D.S. DeBell are now preparing a review of the various factors to be considered throughout a full rotation of red alder."--Conclusion Close

• 7. [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

• 8. [Article] Key issues and future directions of mechanized harvesting : discussions and guidance from working groups

  Recognition of the problems and opportunities in mechanized harvesting should help in development of solutions and maximum realization of its potential. This paper presents feedback from five working groups, ...

  Citation × Citation Citation Abstract Copy Title: Key issues and future directions of mechanized harvesting : discussions and guidance from working groups Author: Oregon State University. Forest Research Laboratory, Olsen, Eldon D., Bettinger, Pete, 1962-, Kellogg, L. D. (Loren D.) Recognition of the problems and opportunities in mechanized harvesting should help in development of solutions and maximum realization of its potential. This paper presents feedback from five working groups, the members of which were involved in mechanized harvesting issues with various organizations in the Pacific Northwest. The groups identified needs and assigned priorities for research in all areas of mechanized harvesting. Most participants thought the working groups were effective. Suggestions for future workshops included encouraging a broader mix of participants, scheduling a longer session for working groups, and providing more guidance to summarizers. Plans for future studies and stronger interactions with other interests in the forest industry may develop from suggestions of the working groups. Title: Key issues and future directions of mechanized harvesting : discussions and guidance from working groups Author: Oregon State University. Forest Research Laboratory, Olsen, Eldon D., Bettinger, Pete, 1962-, Kellogg, L. D. (Loren D.) Recognition of the problems and opportunities in mechanized harvesting should help in development of solutions and maximum realization of its potential. This paper presents feedback from five working groups, the members of which were involved in mechanized harvesting issues with various organizations in the Pacific Northwest. The groups identified needs and assigned priorities for research in all areas of mechanized harvesting. Most participants thought the working groups were effective. Suggestions for future workshops included encouraging a broader mix of participants, scheduling a longer session for working groups, and providing more guidance to summarizers. Plans for future studies and stronger interactions with other interests in the forest industry may develop from suggestions of the working groups. Close

• 9. [Article] Equations and tables predicting gross total stem volumes in cubic feet for six major conifers of southwest Oregon

  Equations and tables predicting gross total stem volumes in cubic feet are presented for Douglas-fir, grand fir, white fir, ponderosa pine, sugar pine, and incense-cedar. The data were gathered in second-growth, ...

  Citation × Citation Citation Abstract Copy Title: Equations and tables predicting gross total stem volumes in cubic feet for six major conifers of southwest Oregon Author: Clyde, Merlise A., Oregon State University. Forest Research Laboratory, Walters, David K., Hann, David W. Equations and tables predicting gross total stem volumes in cubic feet are presented for Douglas-fir, grand fir, white fir, ponderosa pine, sugar pine, and incense-cedar. The data were gathered in second-growth, mixed-conifer stands of southwest Oregon. The basic equations use diameter outside bark at breast height and total tree height as independent variables. Tables and additional equations were developed that incorporate crown ratio for Douglas-fir, grand fir, and white fir. Equations that predict stump diameter, volume below breast height, and volume above breast height also are developed and presented for each species. Title: Equations and tables predicting gross total stem volumes in cubic feet for six major conifers of southwest Oregon Author: Clyde, Merlise A., Oregon State University. Forest Research Laboratory, Walters, David K., Hann, David W. Equations and tables predicting gross total stem volumes in cubic feet are presented for Douglas-fir, grand fir, white fir, ponderosa pine, sugar pine, and incense-cedar. The data were gathered in second-growth, mixed-conifer stands of southwest Oregon. The basic equations use diameter outside bark at breast height and total tree height as independent variables. Tables and additional equations were developed that incorporate crown ratio for Douglas-fir, grand fir, and white fir. Equations that predict stump diameter, volume below breast height, and volume above breast height also are developed and presented for each species. Close

• 10. [Article] Equations for predicting height-to-crown-base, 5-year diameter-growth rate, 5-year height-growth rate, 5-year mortality rate, and maximum size-density trajectory for Douglas-fir and western hemlock in the coastal region of the Pacific Northwest

  Using existing permanent research plot data, we developed equations for predicting height-to-crown-base (HCB), 5-yr diametergrowth rate (delta D), 5-yr height-growth rate (delta H), 5-yr mortality rate ...

  Citation × Citation Citation Abstract Copy Title: Equations for predicting height-to-crown-base, 5-year diameter-growth rate, 5-year height-growth rate, 5-year mortality rate, and maximum size-density trajectory for Douglas-fir and western hemlock in the coastal region of the Pacific Northwest Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Using existing permanent research plot data, we developed equations for predicting height-to-crown-base (HCB), 5-yr diametergrowth rate (delta D), 5-yr height-growth rate (delta H), 5-yr mortality rate (PM), and the maximum size-density trajectory for Douglasfir and western hemlock in the coastal region of the Pacific Northwest. With the exception of the HCB equation, the equations developed for predicting trees from untreated plots agreed in predictive behavior with previously published equations for the study area. The HCB equation predicted shorter HCB (and therefore longer crown lengths [CL]) than previously published equations for the study area. Western hemlock showed no response to fertilization. Modifiers for fertilization response were incorporated into the final equations for predicting delta D, delta H, and PM in Douglas-fir. All three modifiers for Douglas-fir predicted an increase in growth and mortality rates with the amount of nitrogen applied and a decrease with number of years since fertilization, with most of the fertilization effect gone within 15 yr of application. For the delta D and delta H modifiers, the size of the increase varied by the site index (SI) of the plot, with plots of lower site quality showing greater increases. For delta D, fertilization response did not appear to vary by plot density, tree size, or tree position within the plot. Modifiers for thinning response were incorporated into the final equations for predicting tree delta D for both species and delta H for Douglas-fir. For both species, the delta D thinning-effects modifier predicted an increased growth rate with the proportion of the BA removed and a decrease with years since thinning; most of the thinning effect was gone within 10 yr. For Douglas-fir, the delta H thinning-effects modifier predicted a reduced growth rate immediately after thinning, with the size of the reduction increasing with the intensity of thinning. Most of the reduction was gone by about 10 yr. For Douglas-fir, the combined effect on delta D and delta H of applying both thinning and fertilization could be adequately characterized by the product of the thinning modifier and the fertilization modifier. The percent increase in predicted growth rate due to a combined treatment thus was greater than the sum of the percent increases for each treatment alone. Analysis of the maximum size-density trajectory data strongly suggests that plots of neither species approach a single maximum stand density index value (SDI) as they develop. The potential yield for a given site therefore depends, not only on its SI, but also on its maximum SDI. Fertilization does not appear to affect the intercept of the maximum size-density line for Douglas-fir. The strengths and weaknesses of the existing data sets and the modeling and analytical approaches tested during development of these equations are presented to aid future modelers, and alternative modeling approaches are explored. Title: Equations for predicting height-to-crown-base, 5-year diameter-growth rate, 5-year height-growth rate, 5-year mortality rate, and maximum size-density trajectory for Douglas-fir and western hemlock in the coastal region of the Pacific Northwest Author: Hanus, Mark L., Oregon State University. Forest Research Laboratory, Hann, David W., Marshall, David D. Using existing permanent research plot data, we developed equations for predicting height-to-crown-base (HCB), 5-yr diametergrowth rate (delta D), 5-yr height-growth rate (delta H), 5-yr mortality rate (PM), and the maximum size-density trajectory for Douglasfir and western hemlock in the coastal region of the Pacific Northwest. With the exception of the HCB equation, the equations developed for predicting trees from untreated plots agreed in predictive behavior with previously published equations for the study area. The HCB equation predicted shorter HCB (and therefore longer crown lengths [CL]) than previously published equations for the study area. Western hemlock showed no response to fertilization. Modifiers for fertilization response were incorporated into the final equations for predicting delta D, delta H, and PM in Douglas-fir. All three modifiers for Douglas-fir predicted an increase in growth and mortality rates with the amount of nitrogen applied and a decrease with number of years since fertilization, with most of the fertilization effect gone within 15 yr of application. For the delta D and delta H modifiers, the size of the increase varied by the site index (SI) of the plot, with plots of lower site quality showing greater increases. For delta D, fertilization response did not appear to vary by plot density, tree size, or tree position within the plot. Modifiers for thinning response were incorporated into the final equations for predicting tree delta D for both species and delta H for Douglas-fir. For both species, the delta D thinning-effects modifier predicted an increased growth rate with the proportion of the BA removed and a decrease with years since thinning; most of the thinning effect was gone within 10 yr. For Douglas-fir, the delta H thinning-effects modifier predicted a reduced growth rate immediately after thinning, with the size of the reduction increasing with the intensity of thinning. Most of the reduction was gone by about 10 yr. For Douglas-fir, the combined effect on delta D and delta H of applying both thinning and fertilization could be adequately characterized by the product of the thinning modifier and the fertilization modifier. The percent increase in predicted growth rate due to a combined treatment thus was greater than the sum of the percent increases for each treatment alone. Analysis of the maximum size-density trajectory data strongly suggests that plots of neither species approach a single maximum stand density index value (SDI) as they develop. The potential yield for a given site therefore depends, not only on its SI, but also on its maximum SDI. Fertilization does not appear to affect the intercept of the maximum size-density line for Douglas-fir. The strengths and weaknesses of the existing data sets and the modeling and analytical approaches tested during development of these equations are presented to aid future modelers, and alternative modeling approaches are explored. Close