Practical Demonstration of Thinning and Pruning on a Farm Woodlot (EP 499)


To demonstrate desirable forest practices.


The experiment was established at Comox in 1954 in a fairly uniform naturally-regenerated stand consisting mainly of Douglas fir at age 45 years. An area of about 20 acres was divided into 18 rectangles in which one of 3 treatments were applied: thinning and pruning;  thinning and no pruning; and untreated control. A permanent 0.04 ha circular sample plot was established within each replicate in which tree measurements were taken. Thinned removed large, heavily limbed trees with a d/D ratio of 0.98 and a residual basal area of 130 ft2/acre (29.8 m2/ha) and 120 ft2/acre (27.5 m2/ha) on the thinned and thinned & pruned plots respectively. After thinning, all suitable trees within the treatment area were pruned to a height of 18 ft (5.5 m). In 1962 the stand was measured and marked for thinning but a timber sale attracted no bids and the plots were left dormant until 1980.


Final measurement taken in 1988, released in 2001.