Clonal Spread in Second-Growth Stands of Coast Redwood, Sequoia sempervirens1

Coast redwood (Sequoia sempervirens) is one of the rare conifers to reproduce successfully through clonal spread. The importance of this mode of reproduction in stand development is largely unknown. Understanding the importance of clonal spread and the spatial structure of clones is crucial for stand management strategies that would aim to maximize genetic diversity. We have developed genetic markers to identify the clonal structure of nine secondgrowth redwood stands in Jackson Demonstration State Forest, California. Clonal spread was found to be important in the development of these stands, with an average of 6.7 stems being assigned as ramets of the same genet. Although fairy ring structures were commonly identified, we also detected a range of other spatial structures in these second-growth redwood stands. We also detected mixed genets within perceived fairy rings. The extent of clones and their spatial structure may have important evolutionary implications and will also have important consequences on effective population sizes for management purposes. Management and conservation of redwoods will benefit from a better understanding of the dynamics and structure of clonal spread in these forests.