Disturbance and Persistence of Sitka Spruce (Picea sitchensis (Bong) Carr.) in Coastal Forests of the Pacific Northwest, North America

Forests dominated by Picea sitchensis (Bong) and tree growth in gaps to determine if P. sitchensis can Carr. and Tsuga heterophylla (Raf.) Sarg. occupy a narrow persist under a small gap disturbance regime. Tree replace- coastal strip along the Pacific Northwest coast of North ment models derived from tree replacement patterns in America. P. sitchensis is considered seral to T. heterophylla gaps were used to predict abundances of P. sitchensis and but descriptions of groups of P. sitchensis saplings and small T. heterophylla in the next generation. Tree replacement trees in light gaps created by small canopy disturbances models did not predict a decline in P. sitchensis abundance (<0.25 ha) suggest that P. sitchensis may persist by gap- in the next generation. Gaps of 800-1000 m2 appear large phase regeneration after small-scale disturbance. This enough for P. sitchensis to persist in these forests. study combines analyses of the disturbance regime (gap size