LODGEPOLE PINE DEVELOPMENT AFTER EARLY SPACING IN THE BLUE MOUNTAINS OF OREGON

Seedlings were thinned to spacings of 6, 9, 12, 15, and 18 feet and me asured periodically. Twenty-seven years after treatment, quadratic mea n diameters increased curvilinearly (p less than or equal to 0.05) as spacing increased, but total height did not differ significantly (p le ss than or equal to 0.05) with spacing. Corresponding basal areas decr eased curvilinearly (p less than or equal to 0.05), and cubic volumes decreased linearly (p less than or equal to 0.05) as spacing increased . All periodic annual increments differed with period or age. Periodic annual increments for mean diameter and basal area varied curvilinear ly (p less than or equal to 0.05), whereas volume increments varied li nearly (p less than or equal to 0.05) with spacing for each period. He ight increments were greatest at intermediate spacings during some per iods, at wide spacings during other periods, and at the narrowest spac ing during one period. Crown widths increased (p less than or equal to 0.05) as spacing widened. Fifty percent crown cover was attained at a stand density index of about 80 for all spacings. Simulation to a bre ast high age of 100 years indicated that the most merchantable cubic v olume was produced at the 6-foot spacing but that the 12-, 15-, and 18 -foot spacings produced about the same board-foot volume.