Graduation Date
Spring 2026
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Forestry, Watershed, & Wildland Sciences
Committee Chair Name
John-Pascal Berrill
Committee Chair Affiliation
Cal Poly Humboldt Faculty or Staff
Second Committee Member Name
Jeffrey Kane
Second Committee Member Affiliation
Cal Poly Humboldt Faculty or Staff
Third Committee Member Name
Rosanna Overholser
Third Committee Member Affiliation
Cal Poly Humboldt Faculty or Staff
Keywords
Silviculture, Coast redwood, Pyrosilviculture, Fire, Fuels, Multiaged, Tanoak, Retention forestry, Partial harvest
Subject Categories
Forestry
Abstract
Forest managers using retention forestry in western forests need information on regeneration dynamics and fuel development to design stands that are both productive and fire resilient. This study analyzes 10-year remeasurement data from the Redwood Multiaged Experiment in Jackson Demonstration State Forest, California, comparing regeneration and fuel responses across group selection (GS), aggregated (HA), and dispersed (LD, HD) retention treatments. Target relative density (RD) of the residual stand was zero in GS, 13% in LD, and 21% in HA and HD. Measurements included sprout growth and size of redwood and tanoak, seedling and sprout density, and surface fuel loading.
Redwood responded strongly to increasing canopy openness, with basal area and height greatest in GS and lowest in HD. Tanoak showed a more modest response, consistent with greater shade tolerance, and differences between species narrowed under higher retention (HA, HD). Redwood also grew faster than tanoak across all treatments, though growth declined over time for both species. Douglas-fir regeneration was less frequent and did not vary among treatments.
Fuel loads showed few differences among treatments prior to precommercial thinning in the new cohort, 10 years after harvests, but vegetative fuels were highest in more open treatments. Precommercial thinning reduced live fuels and increased fine dead fuels, particularly in treatments that had accumulated greater biomass.
These results highlight a key trade-off: treatments that promote rapid redwood sprout growth and biomass accumulation also increase short-term surface fuel loads following subsequent tending. Effective multiaged management for productivity and resilience in redwood systems therefore requires consideration of regeneration dynamics and fuel treatment strategies over time.
Citation Style
APA 7
Recommended Citation
Fisher, Jud, "Regeneration and fuel loading with varying overstory retention in redwood stands 10 years after transformation to multiaged management" (2026). Cal Poly Humboldt theses and projects. 2570.
https://digitalcommons.humboldt.edu/etd/2570