Download or read book Enhanced Diameter 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 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equations for predicting the 5-yr diameter-growth rate of a tree are presented for eight conifer and nine hardwood tree species from southwest Oregon. Equation parameters for undamaged and damaged trees combined were estimated by weighted nonlinear regression. The resulting equation for Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] explained more than 71% of the variation when validated against an independent data set. These equations are being incorporated into the new edition of ORGANON for southwest Oregon, a model for predicting the development of stands. The equations extend the previous model to older stands and stands with a larger component of hardwood. We explored the effects of specific damaging agents on the 5-yr diameter-growth rates of the five most frequently encountered species and estimated damage correction factors. Damaging agents can impact 5-yr diameter-growth rate significantly and, as a result, can lead over time to diversification in stand structure. Therefore, full characterization of stand development should include prediction of the presence and frequency of the agents damaging trees within the stand and their impact on tree attributes such as total height, height-to-crown-base, diameter-growth rate, height-growth rate, and mortality rate.

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 Forest Growth and Yield Modeling written by Aaron R. Weiskittel and published by John Wiley & Sons. This book was released on 2011-08-22 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forest Growth and Yield Modeling synthesizes current scientific literature and provides insights in how models are constructed. Giving suggestions for future developments, and outlining keys for successful implementation of models the book provides a thorough and up-to-date, single source reference for students, researchers and practitioners requiring a current digest of research and methods in the field. The book describes current modelling approaches for predicting forest growth and yield and explores the components that comprise the various modelling approaches. It provides the reader with the tools for evaluating and calibrating growth and yield models and outlines the steps necessary for developing a forest growth and yield model. Single source reference providing an evaluation and synthesis of current scientific literature Detailed descriptions of example models Covers statistical techniques used in forest model construction Accessible, reader-friendly style

Download or read book Predicting Height for Undamaged and Damaged Trees in Southwest Oregon written by Mark L. Hanus and published by . This book was released on 1999 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Diameter Growth Equations for Fourteen Tree Species in Southwest Oregon written by David W. Hann and published by . This book was released on 1991 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reanalysis of the SMC ORGANON Equations for Diameter growth Rate Height growth Rate and Mortality Rate of Douglas fir written by David W. Hann and published by . This book was released on 2006 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using existing data from untreated research plots, we developed equations for predicting 5-yr diameter-growth rate (delta D5), 5-yr height-growth rate (delta H5), and 5-yr mortality rate (PM5) for Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in the coastal region of the Pacific Northwest. These equations are revisions of the equations constructed in 1995-1997 for the Stand Management Cooperatives (SMC) version of the ORGANON growth-and-yield model, and they have been developed with substantially larger and more comprehensive data sets than were available in 1995-1997. The new delta D5 and delta H5 equations were validated with an independent data set. The PM5 equation was evaluated by comparing 100-yr predictions of Reinekes (1933) stand density index to behavior previously reported from measurements taken on long-term researchplots. The new delta D5, delta H5, and PM5 equations appear to be considerably superior in predictive ability and behavior to the original equations. The effects of the new equations on stand-level predictions were evaluated by comparing the maximum mean annual increments (MAI) in total stem volume (ft3) and associated rotation ages (RA) predicted from the original SMC-ORGANON model to predictions from the revised SMC-ORGANON model. This analysis was done by making 100-yr projections using 170 plots in young stands from the SMC data sets. Some of the ending values for average crown ratio (CR) after 100 yr of projection were near 15%, however, and predictions of basal area (BA) for some of these stands peaked and then declined over stand age. Substituting the HCB equation published by Hann and Hanus in 2004 for predicting crown recession (delta HCB5) eliminated the problem with BA peaking over stand age and resulted in somewhat larger average ending CRs. The 100-yr projections were then made again with the 2004 HCB equation of Hann and Hanus. On average, the revised model reduced RA by 2.1 yr (or 4.3%) and maximum MAI by 55.7 ft3/ac/yr (18.9%).

Download or read book Enhanced Mortality Equations for Trees in the Mixed Conifer Zone of Southwest Oregon written by David W. Hann and published by . This book was released on 2001 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equations for predicting the probability of a tree's dying in the next 5 years are presented for eight conifer and eight hardwood tree species from southwest Oregon. A logistic equation form was used to characterize the probability of mortality. The parameters of the equation were estimated using weighted, maximum likelihood procedures. These equations are being incorporated into the new southwest Oregon version of ORGANON, a model for predicting stand development. In particular, the equations extend the previous model to older stands and and stands with a heavier component of hardwood tree species.

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 Environmental Modelling written by John Wainwright and published by John Wiley & Sons. This book was released on 2013-04-01 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation models are an established method used to investigate processes and solve practical problems in a wide variety of disciplines. Central to the concept of this second edition is the idea that environmental systems are complex, open systems. The authors present the diversity of approaches to dealing with environmental complexity and then encourage readers to make comparisons between these approaches and between different disciplines. Environmental Modelling: Finding Simplicity in Complexity 2nd edition is divided into four main sections: An overview of methods and approaches to modelling. State of the art for modelling environmental processes Tools used and models for management Current and future developments. The second edition evolves from the first by providing additional emphasis and material for those students wishing to specialize in environmental modelling. This edition: Focuses on simplifying complex environmental systems. Reviews current software, tools and techniques for modelling. Gives practical examples from a wide variety of disciplines, e.g. climatology, ecology, hydrology, geomorphology and engineering. Has an associated website containing colour images, links to WWW resources and chapter support pages, including data sets relating to case studies, exercises and model animations. This book is suitable for final year undergraduates and postgraduates in environmental modelling, environmental science, civil engineering and biology who will already be familiar with the subject and are moving on to specialize in the field. It is also designed to appeal to professionals interested in the environmental sciences, including environmental consultants, government employees, civil engineers, geographers, ecologists, meteorologists, and geochemists.

Download or read book Height diameter Equations for Seventeen Tree Species in Southwest Oregon written by David Rolf Larsen and published by . This book was released on 1987 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Extending Southwest Oregon s Douglas fir Dominant Height Growth Equation to Older Ages written by David W. Hann and published by . This book was released on 1998 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Diameter Growth Equations for Fourteen Tree Species in Soutwest Oregon written by David W. Hann and published by . This book was released on 1991 with total page 18 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 2006 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predicting Height for Crown Base for Undamaged and Damaged Trees in Southwest Oregon by Mark L Hanus David W Hann David D Marshall written by Mark L. Hanus and published by . This book was released on 2000 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 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 written by David W. Hann and published by . This book was released on 2003 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Crown condition Classification written by and published by . This book was released on 2007 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Forest Inventory and Analysis (FIA) Program of the Forest Service, U.S. Department of Agriculture, conducts a national inventory of forests across the United States. A systematic subset of permanent inventory plots in 38 States is currently sampled every year for numerous forest health indicators. One of these indicators, crown-condition classification, is designed to estimate tree crown dimensions and assess the impact of crown stressors. The indicator features eight tree-level field measurements in addition to variables traditionally measured in conjunction with FIA inventories: vigor class, uncompacted live crown ratio, crown light exposure, crown position, crown density, crown dieback, foliage transparency, and crown diameter. Indicators of crown health derived from the crown data are intended for analyses at the State, regional, and national levels, and contribute to the core tabular output in standard FIA reports. Crown-condition measurements were originally implemented as part of the Forest Health Monitoring (FHM) Program in 1990. Except for crown diameter, these measurements were continued when the FIA Program assumed responsibility for FHM plot-based detection monitoring in 2000. This report describes in detail the data collection and analytical techniques recommended for crown-condition classification.

Download or read book Nonlinear Regression Modeling written by David A. Ratkowsky and published by . This book was released on 1983 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to regression models; Assessing nonlinearity in nonlinear regression models; Yield-density models; Sigmoidal growth models; Asymptotic regression model; Some miscellaneous models; Comparing parameter estimates from more than one data set; Obtaining good initial parameter estimates; Summary: towatd a unified approach to nonlinear regression modeling.