Coniferous forests account for 78% of the western US forests and store a substantial amount of carbon. Wildfires significantly alter vegetation structure and associated forest carbon stocks.
Climate change is reducing winter snowpack and advancing spring snowmelt across the western United States (US), interacting with El Niño-Southern Oscillation (ENSO) teleconnections that drive spatially predictable interannual fluctuations that contribute to high- or low-snow winters.
Mature and old-growth forests (MOG) provide essential ecosystem services, yet they face increasing threats. Currently, high-intensity, high-severity wildfires are the main driver for loss of MOG on federally managed forests across the United States. Quantifying MOG forests with greatest exposure to stand-replacing wildfires provides essential information for land managers.
The stability of seasonally dry Western mixed-conifer forests is threatened by the history of fire suppression, logging, and now increasing climate-driven aridity. Durable aboveground carbon storage in living trees–a key ecosystem service of these fire-adapted forests–is at risk due to the disruption of natural fire cycles.
Biological legacies (i.e., materials that persist following disturbance; “legacies”) shape ecosystem functioning and feedbacks to future disturbances, yet how legacies are driven by pre-disturbance ecosystem state and disturbance severity is poorly understood—especially in ecosystems influenced by infrequent and severe disturbances.
Restoring a low-intensity, frequent-fire regime in fire-prone forests offers a promising natural climate solution. Management interventions that include prescribed fire and/or mechanical treatments have effectively reduced fire hazards in the Western United States, yet concerns remain regarding their impact on forest carbon storage.
Changing climate is altering the amount of carbon that can be sustained in forest ecosystems. Increasing heat and drought is already causing increased mortality and decreased regeneration in some locations. These changes have implications for landscape carbon storage with ongoing climate change.
Pathways to achieving net-zero and net-negative greenhouse-gas (GHG) emission targets rely on land-based contributions to carbon (C) sequestration. However, projections of future contributions neglect to consider ecosystems, climate change, legacy impacts of continental-scale fire exclusion, forest accretion and densification, and a century or more of management.