Spatial Pattern of Coast Redwood in Three Alluvial Flat Old-Growth Forests in Northern California

The spatial patterns of trees were investigated in old-growth redwood (Sequoia sempervirens [D. Don] End!.) forests located in northern California to guide the design of restoration prescriptions. All stems ^! 15 cm dbh were mapped and measured on three 1.5-ha plots. Patterns for trees in different size classes were analyzed separately with Ripley's K(d) function. Results revealed two patterns. At two sites, trees were randomly distributed throughout the stand and size classes were spatially independent of each other at scales of 0-50 m. At one site, a clumped spatial pattern was revealed for smalland medium-sized tree groups at small scales, whereas a random spatial pattern was detected for large trees at scales of 0-50 m, In addition, significant positive deviation from spatial independence at small scales suggested an attraction between tree groups. The spatial pattern of regeneration (trees <15 cm dbh) was described using quadrat-based analyses. Regeneration was clumped at all three sites. Results indicate that old-growth redwood forests occurring on alluvial flats have different spatial patterns for similar size classes of trees despite the similarities in topography and stand structural characteristics. For land managers interested in restoration, these results suggest that past thinning guides that emphasized uniform spacing may not be appropriate in restoration efforts. Instead, trees should be retained in clumps or in random spatial patterns. FOR. SCI. 54(3):294-302.