Data: The magnitude and pace of photosynthetic recovery after wildfire in California ecosystems

Wildfire modifies the short- and long-term exchange of carbon between
terrestrial ecosystems and the atmosphere, with impacts on ecosystem
services such as carbon uptake. Dry western United States forests
historically experienced low-intensity, frequent fires, with patches
across the landscape occupying different points in the fire-recovery
trajectory. Contemporary perturbations, such as recent severe fires in
California, could shift the historic stand-age distribution and impact the
legacy of carbon uptake on the landscape. Here we combine flux
measurements of gross primary production (GPP) and chronosequence analysis
using satellite remote sensing to investigate how the last century of
fires in California impacted the dynamics of ecosystem carbon uptake on
the fire-affected landscape. A GPP recovery trajectory curve of more than
five thousand fires in forest ecosystems since 1919 indicated that fire
reduced GPP by 157.4 ± 7.3 gCm-2yr-1 (mean ± standard error,
n=1926) in the first year after fire, with average recovery to pre-fire
conditions after ~12 years. The largest fires in forested ecosystems
reduced GPP by 393.8 ± 15.7 gCm-2yr-1 (n=401) and took more than two
decades to recover. Recent increases in fire severity and recovery time
have led to nearly 9.9 ± 3.5 MMT CO2 (3-year rolling mean) in
cumulative forgone carbon uptake due to the legacy of all fires on the
landscape, complicating the challenge of maintaining California's
natural and working lands as a net carbon sink. Understanding these
changes is paramount to weighing the costs and benefits associated with
fuels management and ecosystem management for climate change mitigation.