Figure 1. Delayed tree mortality from wildland fire is a function the
heat flux (time-integrated energy release) or “dose” on numerous
physiological responses. Heat flux includes the heat transfer processes
of radiation, convection and conduction. A) Potential physiological
responses (oranges lines) over time to a fire dose relative to baseline.
Dots at end of orange lines indicate tree death, while arrows indicate
survival. Responses potentially affected by fire include, but are not
limited to, photosynthetic rate (A), defense traits, predawn water
potential causing 50% loss of stem conductivity (P50),
and stomatal conductance (gs). B) Long-term, tree
mortality from fire is a function of the total heat flux , plant water
stress (Ψp) and ambient air temperature
(Ta) at the time of fire, physiological responses,
species traits, and exogenous factors. C) Tree binary endpoint
(mortality or survival) to a fire dose. The solid line is the average
tree response and dashed lines reflect the lower and upper bounds of
response based on species traits and environmental stress. The grey zone
denotes possible range of a species response or biological plasticity to
fire; grey arrows provide examples of ranges of variation in mortality
from the same heat flux or variation in heat flux that causes the same
level of mortality.