"Forest response to increasingly frequent fire and drought disturbances" by Kevin G. Willson
 

Biology ETDs

Publication Date

Fall 12-15-2024

Abstract

Changes in fire regimes and drought intensity have increased fire and drought severity in southwestern forests, decreasing forest resilience to recent changes in climate. As tree response and regeneration after disturbance are critical for forest persistence, this dissertation assesses ponderosa pine regeneration patterns after high-severity fire, tree growth response to the reintroduction of frequent-fire, and tree growth response to multiyear droughts in fire-maintained and fire-excluded forests. We found that high-severity patch locations were more likely to regenerate when positioned downwind, downslope, and near intact forest. Trees had similar growth responses to first-entry fires and reburns following long-term fire-exclusion. After experiencing frequent-fire, trees had smaller reductions in stomatal conductance during and after multi-year droughts than trees in fireexcluded forests. Our findings demonstrate that abiotic factors alter patch regeneration, trees retain vigor after frequent, low-severity fires, and fire-maintained forests contain trees with less water stress than trees in fire-excluded forests.

Document Type

Dissertation

First Committee Member (Chair)

Matthew Hurteau

Second Committee Member

Scott Collins

Third Committee Member

William Pockman

Fourth Committee Member

Ellis Margolis

Fifth Committee Member

Camille Stevens-Rumann

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