Data from: Spatial variability in tree regeneration after wildfire delays and dampens future bark beetle outbreaks

Climate change is altering the frequency and severity of forest
disturbances such as wildfires and bark beetle outbreaks, thereby
increasing the potential for sequential disturbances to interact.
Interactions can amplify or dampen disturbances, yet the direction and
magnitude of future disturbance interactions are difficult to anticipate
because underlying mechanisms remain poorly understood. We tested how
variability in postfire forest development affects future susceptibility
to bark beetle outbreaks, focusing on mountain pine beetle (Dendroctonus
ponderosae) and Douglas-fir beetle (Dendroctonus pseudotsugae) in forests
regenerating from the large high-severity fires that affected Yellowstone
National Park in Wyoming in 1988. We combined extensive field data on
postfire tree regeneration with a well-tested simulation model to assess
susceptibility to bark beetle outbreaks over 130 y of stand development.
Despite originating from the same fire event, among-stand variation in
forest structure was very high and remained considerable for over a
century. Thus, simulated emergence of stands susceptible to bark beetles
was not temporally synchronized but was protracted by several decades,
compared with stand development from spatially homogeneous regeneration.
Furthermore, because of fire-mediated variability in forest structure, the
habitat connectivity required to support broad-scale outbreaks and
amplifying cross-scale feedbacks did not develop until well into the
second century after the initial burn. We conclude that variability in
tree regeneration after disturbance can dampen and delay future
disturbance by breaking spatiotemporal synchrony on the landscape. This
highlights the importance of fostering landscape variability in the
context of ecosystem management given changing disturbance regimes.