Author: David W. Hann Publisher: ISBN: Category : Douglas fir Languages : en Pages : 88
Book Description
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.
Author: Aaron R. Weiskittel Publisher: John Wiley & Sons ISBN: 0470665009 Category : Science Languages : en Pages : 431
Book Description
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
Author: David W. Hann Publisher: ISBN: Category : Forests and forestry Languages : en Pages : 58
Book Description
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.
Book Description
The Management of Industrial Forest Plantations. Theoretical Foundations and Applications provides a synthesis of current knowledge about industrial forestry management planning processes. It covers components of the forest supply chain ranging from modelling techniques to management planning approaches and information and communication technology support. It may provide effective support to education, research and outreach activities that focus on forest industrial plantations management. It may contribute further to support forest managers when developing industrial plantations management plans. The book includes the discussion of applications in 26 Management Planning in Actions boxes. These applications highlight the linkage between theory and practice and the contribution of models, methods and management planning approaches to the efficiency and the effectiveness of industrial plantations management planning.
Author: David W. Hann Publisher: ISBN: Category : Conifers Languages : en Pages : 42
Book Description
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.
Author: John Wainwright Publisher: John Wiley & Sons ISBN: 0470749113 Category : Technology & Engineering Languages : en Pages : 493
Book Description
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.
Author: David W. Hann Publisher: ISBN: Category : Douglas fir Languages : en Pages : 28
Book Description
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%).
Author: David A. Ratkowsky Publisher: ISBN: Category : Mathematics Languages : en Pages : 296
Book Description
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.
Author: David W. Hann
Author: Aaron R. Weiskittel
Author: David W. Hann
Author: José G. Borges
Author: David W. Hann
Author: John Wainwright
Author: David W. Hann
Author: 
Author: Oregon State University. Swiss Needle Cast Cooperative
Author: David A. Ratkowsky