Drivers of post-fire conifer regeneration in the southern Cascades, CA.

Keywords: Fire, Forest regeneration, Vegetation dynamics
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 09:40 AM (Eastern Time (US & Canada)) - 2/25/2022 11:00 AM (Eastern Time (US & Canada))
Room: Virtual 42

Abstract

As the legacy of fire suppression and climate change interact to produce larger and more intense fires in western forests, forests adapted to frequent, low severity fire may be unable to recover from these uncharacteristic disturbances. Poor tree regeneration may result in conversion to non-forested vegetation types, and over broad spatial scales this may result in widespread forest cover loss. Though it is widely accepted that burn severity, distance to seed source, ground cover characteristics, and shrub competition are important drivers of regeneration, further research is needed to understand spatial variability in tree regeneration and composition changes driven by shifting fire regimes. 189 plots in () burn scars in Lassen Volcanic National Park were sampled in summer 2021. In each plot, conifer regeneration by species was recorded to relate to local and landscape scale cover and other characteristics. To characterize relationships between these variables, a Random Forest (RF) model will be employed. RF particularly useful for nonlinear relationships between predictors and the response variable, and will be used to generate models of overall regeneration density and presence/absence of common conifer species observed. We expect that previously established relationships between regeneration and previously mentioned variables will hold true, but that the composition of competing vegetation and other metrics of seed source will further explain patterns of regeneration. We expect that landscape context will determine the presence and abundance of regeneration, and that local conditions will act as a final filter to the presence and composition of the regeneration cohort.