Test plantations were established in western Washington and Oregon to compare tree growth at six initial planting densities ranging from 300 to 2960 trees/ha (120 to 1200/acre). A size-density relation was visually apparent 3 to 4 years after planting. Inventory data from the oldest 11 trials (5 or 6 years after planting) showed that initial spacing strongly influenced early growth of coast Douglas-fir (Pseudotsuga menziesii(Mirb.) Franco var.menziesii). Average height and diameter at breast height were progressively larger as planting density increased; at the widest spacing (lowest stand density), average height was 75% and average diameter at breast height was 67% of that at the closest spacing. We have no firm explanation for the early faster tree growth at close spacings. Trees planted at 2960 trees/ha (1200 trees/acre) attained breast height (1.3 m) 2 years earlier than trees planted at a density of 300/ha (120/acre). This finding has practical significance to current efforts to achieve early establishment of plantations.