Assessing potential tradeoffs for carbon sequestration, wildlife habitat, and fire risk mitigation with climate change and fire management on the Olympic Peninsula, Washington, USA

Forests of the maritime Pacific Northwestern USA may have high carbon sequestration potential and high potential to sustain older forest and other forest structural types for threatened and valued wildlife species, via their high productivity and moderate to infrequent fire regimes. With climate change, there may be shifts in incidence and severity of fire, especially in the drier areas of the region, via changes to forest productivity and hydrology, and consequent effects to C sequestration and forest structure. To explore this issue in an area with relatively limited alternatives for fire and fuels management, I assessed potential effects of varying approaches to fire management (no suppression/wildland fire management/highly effective fire suppression) under two climate change scenarios on future C sequestration and wildlife habitat in Olympic National Park, WA, over a 500-year simulation period. I used the simulation platform FireBGCv2, which contains a mechanistic, individual tree succession model, a spatially explicit climate-based biophysical model that uses daily weather data, and a spatially explicit fire model that incorporates ignition, spread, and effects on ecosystem components, with stochastic properties implemented in a spatial domain. C sequestration patterns varied over time and spatial and temporal patterns differed somewhat depending on the climate change scenario applied and the fire management methods employed. Under the more extreme climate change scenario with little fire suppression, fires were most frequent and severe and older forest habitat was reduced, but early successional forest important to some components of other wildlife habitat were promoted. General trends were similar under the more moderate climate change scenario but spatial patterns differed. Some areas of the landscape served as refugia for older forest under increasing frequency of high severity fire and may be promising as anchors for the maintenance of habitat in a landscape experiencing increasing frequency of disturbance with climate change.