Experimental Pruning of Douglas-fir in British Columbia

This document details extensive trials conducted in British Columbia to establish the most effective and economical methods for pruning second-growth Douglas fir, an operation deemed essential for producing the clear wood required by the growing plywood industry. The experiments concluded that up to 50 per cent of total tree height could be safely removed without detriment to growth, suggesting that performing the entire prune up to 20 feet in one operation is the cheapest method for minimizing labor and administrative costs. While different tools were tested, the hand-saw and ladder combination proved superior in speed, worker preference, and cut quality, resulting in smooth cuts that heal quickly and cleanly. The report emphasizes that timely pruning and the selection of stands with a favorable diameter growth rate are crucial for maximizing the financial success of the timber operation.