Graduation Date
Fall 2021
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Forestry, Watershed, & Wildland Sciences
Committee Chair Name
David Greene
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Buddhika Madurapperuma
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Jeffrey Kane
Third Committee Member Affiliation
HSU Faculty or Staff
Subject Categories
Forestry
Abstract
As wildfire becomes increasingly frequent, many plant populations risk local extirpation if fire recurs too soon, a problem dubbed “immaturity risk”. We studied the regeneration of a serotinous conifer species, knobcone pine (Pinus attenuata), as a function of the time between high-severity fires (6-79 years). We evaluated age, cone production, and regeneration at two burned sites in northern California, the Ranch Fire (2018) in Mendocino National Forest, and the Carr Fire (2018) in Whiskeytown National Recreation Area. We found an average of 30.5 filled seeds in closed, brown cones (42% viability of filled seeds). The bulk of the older (gray) cones were partially or fully open, and thus available seed in them at the time of fire was approximately halved. Adjusting for survivorship, the estimated minimum age for knobcone pine to produce one recruit per tree (self-replacement) was 8.2 years. Characterizing the probability of burning as a negative exponential model and using an 81-year return time, we found the likelihood of reburn before 8.2 years was 0.09. Our study demonstrated the importance of understanding the size and time to reproductive maturity in serotinous tree species to adequately quantify immaturity risk. Based on our results and current estimates of return time, we suggested that immaturity risk is very low for knobcone pine. Our approach could be broadly applied to better quantify immaturity risk in other conifer species.
Citation Style
APA
Recommended Citation
Marlin, Katherine, "Evaluating immaturity risk in young stands of the serotinous knobcone pine (Pinus attenuata)" (2021). Cal Poly Humboldt theses and projects. 515.
https://digitalcommons.humboldt.edu/etd/515