Enhanced diameter-growth-rate equations for undamaged and damaged trees in Southwest Oregon
By: by David W. Hann, Mark L. Hanus.
Contributors: Hanus, Mark L.; Oregon State University. Forest Research Laboratory.
Series: Research contribution -- 39.; Research contribution (Oregon State University. Forest Research Laboratory) -- 39.
Publisher: Oregon State University, College of Forestry, Forest Research Laboratory
Published: 2002
Place of publication: [Corvallis, Or.]
Language: eng
Number of pages: 54
Subjects: Forests and forestry -- Oregon -- Measurement -- Mathematical models.; Trees -- Oregon -- Growth -- Mathematical models.
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.
Notes: "December 2002."

Includes bibliographical references (p. 45-49).

Also issued online.