T14 Advancements in the Science and Management of Wildfire Impacts on the Critical Zone

Sunday, 15 October 2023
8:00 AM - 12:00 PM
317 / 318

WILDFIRE MEDIATED CHANGES IN WESTERN FORESTS: HOW FOREST CONVERSIONS MAY INFLUENCE MANAGEMENT AND LONG-TERM PROCESSES

Paper number: T14-4
Program: Technical Sessions
Time: 8:35 AM – 8:55 AM

Authors

Abstract

Western North American mountains provide 70% of the drinking water to human populations of the west, however these water sources and associated landscapes are increasingly impacted by large, high severity wildfires. Land management agencies have long relied on the expectation that coniferous forests would regenerate following such events, which in turn restores many of the ecosystem services provided by conifer forests. However, a growing body of evidence has demonstrated that many of these forests are converting to non-forests or deciduous-dominated forests, leading to long-term changes in these ecosystem services, such as hydrologic land surface processes that control post-fire runoff and erosion response, biogeochemical processes relevant to downstream water quality, and snowpack accretion and melt mechanics Here we examined the prevalence of regeneration failure and explored how managers are addressing these issues. Over 10,000 site level field-based surveys demonstrate that high severity wildfires have already resulted in little to no regeneration even up to 30 years post-fire, and models predict even lower regeneration in the coming decades especially following high severity fires in our dry, low-elevation forests. We present an historical analogue of forest conversions that demonstrate largely dynamic forests and illustrate that progressive climate-forward reforestation may be appropriate in our changing climate. Though policy barriers may exist, critical management decisions are necessary to ensure the persistence of conifer forests where they continue to be climatically suitable and climate adaptation strategies to facilitate native community transitions where forests are no longer viable.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-390180

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