Upland Log Volumes and Conifer Establishment Patterns in Two Northern Upland Old-Growth Redwood Forests, A Brief Synopsis

We characterized the volume, weight and top surface area of naturally fallen logs in an oldgrowth redwood forest, and quantified conifer recruit densities on these logs and on the surrounding forest floor. We report significantly greater conifer recruit densities on log substrates as compared to the forest floor. Log substrate availability was calculated on a per hectare basis using the line-intersect method. This method is used to estimate the amount of coarse woody debris present, by measuring log diameters intersected along randomly oriented transects. Conifer recruitment on intersected logs was characterized by recording recruit species, height class and substrate for each established individual. Conifer recruit densities on the forest floor were obtained for two old-growth redwood stands by establishing narrow strip plots. We found redwood logs of intermediate decay to be the most abundant woody substrate available for conifer recruitment. Where conifers had established on the forest floor, we found them most frequently on exposed mineral soil. These results confirm the use of logs by conifers in early establishment and growth, and suggest these substrates may affect stand composition and structure over the course of centuries. Differences in life-history traits between redwood and a potential competitor, western hemlock, along with the reported recruit densities, suggest redwood will remain the dominant conifer species in these stands, in the absence of significant disturbance.