A mismatch in wildfire impact reduction and ecological restoration in western U.S. fuel treatments

Abstract

A century of fire suppression has made historically fire-adapted forests across the western U.S. denser and dominated by fire-intolerant trees, leading to severe fires. Fuel treatments aim to reduce wildfire impact and restore fire-adapted forests. Ecological theory suggests these objectives need not align: protecting the existing, fire-maladapted stand may prevent fire-tolerant seedling recruitment. Using Forest Inventory and Analysis data on 81,621 trees and 41,328 seedlings across 11 western U.S. states, we show that fuel treatments increase tree survival, but benefits are largest for fire-intolerant trees, fade within nine years, and come with no seedling composition shift towards fire-tolerant species. Concluding, fuel reduction reduces wildfire impacts but does not restore fire-adapted forests. Without changes in treatment design, long-term resilience will require repeated intervention.