Young-Growth Redwood Stands Respond Well to Various Thinning Intensities

Abstract Three 45- to 50-yr-old redwood (Sequoia sempervirens) sawtimber stands spanning a substantial portion of the species' commercial range were thinned to three stocking levels. Treatments were low thinnings leaving 25%, 50%, 75%, and 100% of the before-treatment stand density, expressed as basal area/ac. Trees were measured for dbh, and a sampling of heights was taken for volume estimations at 0, 5, 10, and 15 yr after thinning. Leave trees responded strongly to the increased growing space, in spite of the vigorous stump sprouting of cut trees. Stand growth in basal area and volume varied narrowly among treatments. Overall, volume production was significantly different only in the 25% leave plots where sites were not fully occupied by the leave trees. Results illustrate the similarity between two growth/growing stock theories which appear to conflict. We conclude that 50% of the basal area in fully stocked stands could be removed in a low thinning without significant loss in volume production. West. J. Appl. For. 9(4):106-112.