Graduation Date

Spring 2019

Document Type

Thesis

Program

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

Committee Chair Name

Dr. John-Pascal Berrill

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Kevin Boston

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Dr. Harold Zald

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Forestry

Abstract

There is increased interest in multiaged management as a silvicultural and restoration tool in redwood forests of California. The effect of varying residual densities and spatial arrangements on residual stand damage, tree growth and regeneration was studied in a multicohort silviculture experiment on Jackson Demonstration State Forest. Four treatments varying in residual stand density or spatial arrangement were replicated at four sites. The experiment provided 4-year periodic growth measurements of residual trees and annual measurements of redwood and tanoak sprout height increments. Residual trees were more likely to sustain bole scarring when retained at higher densities. Crown damage was more likely to be sustained by smaller trees. From 2-6 years after partial harvesting, redwood trees grew faster than Douglas-fir or tanoak following harvest. The height increment of dominant redwood stump sprouts was much greater than dominant tanoak sprouts across all treatments and the growth of both species was directly correlated to understory light. No differences were detected for any dependent variables between dispersed and aggregated retention. No differences in sprout growth were detected when retaining a residual tree on the same root system as sprouting redwood stumps when compared against sprouts growing on a root system after all redwood stems were cut. Overall, these results suggest that managers have flexibility to manage multiaged redwood stands at different densities, and that retention of low densities of large trees will provide a good balance between overstory tree growth and understory development in multiaged stands while reducing incidences of residual stand damage.

Citation Style

APA

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