Height Growth Rate of Douglas-Fir: A Comparison of Model Forms

• DOI: 10.1093/forestscience/34.1.165
• Publication Date: 2024-04-10T12:44:41Z
• Authors: David W. Hann; Martin W. Ritchie
• Keywords: Douglas fir; Tree (set theory); Data set

Abstract Five model forms were evaluated for their ability to predict height growth rate of individual Douglas-firs (Pseudotsuga menziesii [Mirb.] Franco) growing in even or uneven-aged stands southwest Oregon. Three models had been previously used Douglas-fir; the fourth was a simple modification one these, and fifth developed this study by means multidimensional graphing modeling. Two age-dependent, that they transformations stand age, three age-independent. The techniques provided lowest mean squared error both an even-aged data set (1,763 observations) combined even- (2,242 observations). five verified on randomly drawn subset consisting 241 observations. Again with residual error. Independent variables are crown closure at top tree, ratio, potential as predicted existing dominant equation. resulting is age-independent can be applied trees stands. Multidimensional most useful modeling complex nonlinear surface. For. Sci. 34(1):165-175.