Establishment of permanent sample plots and analysis of stand characteristics for interior Douglas-fir forests

Abstract

In order to study the dynamics of uneven-aged stands of interior Douglas-fir,Pseudotsuga menziesii var. glauca (Mirb.) Franco in future, six permanent sample plots were set up on the Knife Creek Block of the Alex Fraser Research Forest of University of British Columbia. The measurements and observations for all living trees within the boundaries of a plot were made, including DBH(diameter at breast height), TTH(total tree height), height to lowest living branch, crown diameter, tree vigor, angle of lean, distance of lean, direction of lean and tree location. Based on the data, some stand characteristics of the plots were analyzed simply and preliminarily. Results showed that most of the interior trees on the plots are ranged 10–20 cm in distribution of DBH class, and 2–6 m in distribution of TTH class. Trees with different sizes, however, are distributed unevenly. The relationship between total tree height and diameter at breast height follows a quadratic distribution, Y=a+bX+cX².

Keywords

Permanent sample plot / Stand analysis / Douglas-fir