Event Title

Low-severity Fire Impacts Snag Dynamics in an Old-growth Forest: Does Tree Neighborhood Matter?

Presenter Information

Kendall Becker

Location

USU Eccles Conference Center

Event Website

https://www.restoringthewest.org/

Streaming Media

Abstract

Disturbance and legacy creation represent a widely referenced but poorly understood phase of forest development. Biological legacies that remain after a disturbance in the form of snags and logs function as structural components that provide habitat, affect snow retention, promote soil development, and influence fire spread. We present the trajectories of 34,246 trees and 4,426 snags before and after a low- to moderate-severity fire burned our 25.6-ha permanent study area in an unlogged, 500-year-old Abies concolor–Pinus lambertiana (white fir–sugar pine) forest in Yosemite National Park. Mean pre-fire tree mortality and snag fall rates were 1.6% and 5.4% for Abies concolor, and 2.2% and 4.3% for Pinus lambertiana; fire-year tree mortality, snag fall, and snag consumption rates were 65.1%, 9.2%, and 29.3% for A. concolor, and 55.2%, 11.6%, and 29.1% for P. lambertiana. Snag consumption rates increased with decay class, were negatively correlated with diameter for stems in early stages of decay, but were independent of diameter for stems in advanced stages of decay. These results show that low- to moderate-severity fire increases the snag population and shifts snag demography toward smaller, less decayed constituents.

Comments

Kendall has a B.S. in Applied Physics from Yale University and an M.S. in Ecosystem Analysis from the University of Washington. Since 2011 she has spent her summers in the Sierra Nevada studying the effects of fire on forests. She is currently pursuing a PhD in Ecology at USU.

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Oct 18th, 11:30 AM Oct 18th, 11:45 AM

Low-severity Fire Impacts Snag Dynamics in an Old-growth Forest: Does Tree Neighborhood Matter?

USU Eccles Conference Center

Disturbance and legacy creation represent a widely referenced but poorly understood phase of forest development. Biological legacies that remain after a disturbance in the form of snags and logs function as structural components that provide habitat, affect snow retention, promote soil development, and influence fire spread. We present the trajectories of 34,246 trees and 4,426 snags before and after a low- to moderate-severity fire burned our 25.6-ha permanent study area in an unlogged, 500-year-old Abies concolor–Pinus lambertiana (white fir–sugar pine) forest in Yosemite National Park. Mean pre-fire tree mortality and snag fall rates were 1.6% and 5.4% for Abies concolor, and 2.2% and 4.3% for Pinus lambertiana; fire-year tree mortality, snag fall, and snag consumption rates were 65.1%, 9.2%, and 29.3% for A. concolor, and 55.2%, 11.6%, and 29.1% for P. lambertiana. Snag consumption rates increased with decay class, were negatively correlated with diameter for stems in early stages of decay, but were independent of diameter for stems in advanced stages of decay. These results show that low- to moderate-severity fire increases the snag population and shifts snag demography toward smaller, less decayed constituents.

https://digitalcommons.usu.edu/rtw/2017/Oct18/14