Master of Science degree with a major in Natural Resources, option Forestry, Watershed, & Wildland Sciences
Committee Chair Name
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Susan E. Marshall
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Deborah S. Page-Dumroese
Third Committee Member Affiliation
Community Member or Outside Professional
In northern California, a cut-to-length (CTL) system was used for the first time to harvest young redwood forests (Sequoia sempervirens (Lamb. ex D. Don) Endl.). However, landowners and public agencies are concerned about the potential negative impacts of CTL logging to soils and residual trees since the extent and amount of CTL impacts are unknown in these forests. This study was designed to (1) determine soil physical property using bulk density (BD) and hydraulic conductivity (HC) (2) examine the characteristics of stand damage after CTL harvesting, and (3) compare the scar size differences between tree growing patterns (individuals vs. clumps). Soil samples were collected from transects at two locations (track and center) on forwarder trails and reference points at three levels of soil depths (0-5, 10-15, and 20-25 cm), and HC data on the soil surface were measured adjacent to the BD sample point. Stand damage was assessed regardless of scar size. I found 25 to 30% increase in BD at 0-5 cm of soil depth on the track compared to reference, but HC showed the inconsistent results due to high variability, so a greater size of HC samples would be needed. Approximately, 16.2-32.2% of residual trees were damaged during operations, and I detected that most damage was located near the forwarding trails and ground level. In addition, I found the larger-sized-scars on clumped trees compared to individual trees in scar width and length. CTL thinning operations may be viable, however, future studies should be performed after few years to evaluate the feasibility of this harvesting system on longer-term tree growth.
Hwang, Kyungrok, "Impacts on soils and residual trees from cut-to-length thinning operations in California's redwood forests" (2018). Cal Poly Humboldt theses and projects. 167.