Graduation Date

Fall 2016

Document Type

Dissertation/Thesis

Program

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

Committee Chair Name

Stephen C. Sillett

Committee Chair Email

prof.sillett@gmail.com

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Robert Van Pelt

Second Committee Member Email

abies2@u.washington.edu

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Jeffrey M. Kane

Third Committee Member Email

Jeffrey.Kane@humboldt.edu

Third Committee Member Affiliation

HSU Faculty or Staff

Abstract

Mature second-growth coast redwood (Sequoia sempervirens) forests are an important and uncommon resource in the redwood region. Development of second-growth redwood forests beyond rotation age (~50 years) is not well understood. Continuous long-term data are especially lacking, considering that the maximum possible age of second-growth stands is now over 150 years. Two permanent observation plots in Arcata, CA, established in 1923 by Woodbridge Metcalf and last measured in 1990, provide a unique opportunity to examine the development of coast redwood forest regenerating after logging in ~1880. We surveyed the Metcalf plots using modern methods and assembled a complete dataset from 1923 to 2015. We also built new allometric models for second-growth coast redwood to predict tree-level quantities such as total biomass and leaf area from ground-based measurements. The Metcalf plots nearly doubled in total basal area over the study period, reaching 124 and 143 m2 ha-1, and redwood increased in proportional dominance as the non-redwood species steadily declined in number. These results, along with substantial density-independent mortality, suggest a transition to a maturation stage of forest development at ~83 years since logging. In the most recent surveys (~135 years since logging), the leaf area index values of trees alone for the Metcalf plots (9.8 and 12.7) are similar to nearby old-growth forests (11.6-15.9). Our results from relatively unmanaged conditions can be compared to silvicultural treatments of regenerating coast redwood forest meant to accelerate development of old-growth characteristics, especially as treated stands move beyond rotation age.

Citation Style

Forest Ecology and Management

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