Retention of needles and seeds on logs in Picea sitchensis - Tsuga heterophylla forests of coastal Oregon and Washington

Logs are a major seedbed in Picea sitchensis — Tsuga heterophylla forests; therefore, the interception and retention ofseeds on these surfaces is a potential limitation on tree recruitment. The ability of log surfaces within Picea—Tsuga foreststo retain needles and seeds was studied at Cascade Head Experimental Forest, Oregon. Moss- and litter-covered surfacesretained many (48-98%) of the seeds and needles placed on them, but rotten wood, sound wood, and bark of Tsuga hetero-phylla, Picea sitchensis, and Pseudotsuga menziesii retained few (0-8%). Examination of logs mapped in five Picea sitchen-sis — Tsuga heterophylla stands in Oregon and Washington indicated a mean projected log cover of 9.9%. Thin ( 5 cm) moss mats were the most abundant log surfaces and covered 59 and 25% of the logs, respectively. Analysisof data on seedbed coverage, retentive characteristics, and seedbed-specific seedling survival indicated approximately 1%of a seed cohort would survive the 1st year on log surfaces.