Ninety-two years of tree growth and death in a second-growth coast Redwood Forest

Author

Benjamin Iberle, Humboldt State UniversityFollow

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 Affiliation

HSU Faculty or Staff

Second Committee Member Name

Robert Van Pelt

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Jeffrey M. Kane

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

Recommended Citation

Iberle, Benjamin, "Ninety-two years of tree growth and death in a second-growth coast Redwood Forest" (2016). Cal Poly Humboldt theses and projects. 4.
https://digitalcommons.humboldt.edu/etd/4