Establishment of salmonberry, salal, vine maple, and bigleaf maple seedlings in the coastal forests of Oregon

Abstract

To identify seedling regeneration niches for four coastal Oregon shrub and hardwood species (salmonberry (Rubusspectabilis Pursh), salal (Gaultheriashallon Pursh), vine maple (Acercircinatum Pursh), and bigleaf maple (Acermacrophyllum Pursh)) we studied the seed predation, emergence, survival, and growth of these species on disturbed and undisturbed soil in thinned, unthinned, and clear-cut conifer stands on two sites in the Oregon Coast Ranges. For all species, seedling emergence and survival were greater in thinned stands than in clearcuts or unthinned stands. In addition, emergence of salmonberry and salal was greater on mineral soil than on soil in which the organic layers were intact. After four years, height of salmonberry was greatest in the clearcuts, where it averaged 23 cm. Bigleaf maple and vine maple, which were heavily browsed in the clearcuts, reached their greatest height in the thinned stands, averaging 16 and 15 cm, respectively. Salal seedlings survived only in thinned stands and grew slowly, reaching a height of only 4–5 cm in 4 years. Seedling emergence and predation both were related to seed size. On both disturbed and undisturbed soil, vine and bigleaf maple, the species with the largest seeds, had the highest rates of emergence but also the highest rates of seed predation among the four species.