Graduation Date

Spring 2018

Document Type



Master of Science degree with a major in Natural Resources, option Forestry, Watershed, & Wildland Sciences

Committee Chair Name

Han-Sup Han

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

Subject Categories



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.

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