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• 1. [Article] Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir

  The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) ...

  Citation × Citation Citation Abstract Copy Title: Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir Author: Faqir Mohammad Khan The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)tree. Data on 237 and 302 trees from Black Rock Forest Management Research Area, Polk County, Oregon, and scattered plots in the State of Washington respectively were analysed in a stepwise regression procedure. The results of regression analyses showed that: a) Direct estimation of diameter inside bark at various upper stem points yield better results than expressing it as a ratio of diameter outside bark as practised previously. b) Diameter inside bark at various heights up the stem has a high positive correlation with its respective diameter outside bark, and a negative correlation with height itself. c) Bark ratio at breast height has been found to have a positive correlation with such ratio at upper stem points; both are negatively related to tree age. Regression equations are presented for estimating diameter inside bark at various upper stem points. These equations are recommended for practical use under stand conditions comparable to those from where the original data were obtained. Title: Developing an equation for making estimates of diameter inside bark at various heights up the stem in Douglas-fir Author: Faqir Mohammad Khan The purpose of this thesis was to develop a suitable multiple regression equation for making estimates of diameter inside bark at various heights up the bole in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)tree. Data on 237 and 302 trees from Black Rock Forest Management Research Area, Polk County, Oregon, and scattered plots in the State of Washington respectively were analysed in a stepwise regression procedure. The results of regression analyses showed that: a) Direct estimation of diameter inside bark at various upper stem points yield better results than expressing it as a ratio of diameter outside bark as practised previously. b) Diameter inside bark at various heights up the stem has a high positive correlation with its respective diameter outside bark, and a negative correlation with height itself. c) Bark ratio at breast height has been found to have a positive correlation with such ratio at upper stem points; both are negatively related to tree age. Regression equations are presented for estimating diameter inside bark at various upper stem points. These equations are recommended for practical use under stand conditions comparable to those from where the original data were obtained. Close