Ecohydrology
Group
Department
of Geography
& Department of Environment and
Sustainability
Annually,
1-3 percent of all trees die from
drought-related causes. Extreme
drought and heat combined with
unreliable access to water threaten
the security of plant-based food and
fiber production. Drought and high
temperatures alter the growth
promotion and pathogen protection
benefits plants receive from the soil
microbiome. These problems involve
complex systems that require both
observations and biophysical
process-based modeling.
We ask know do how plants survive in
stressful environments? To answer this
question we combine measured plant
traits, meteorological data, and biophysical
process-based models. Our
models simulate plant water transport,
xylem cavitation, photosynthesis, and
above-ground and below-ground growth
using physical equations and
biological principles. By taking a
systems approach our models reveal
emergent plant traits, water and
carbon cycling, and plant-microbe
associations. Our ongoing projects and
related products are described
below.
Heat,
Drought, and Tree Mortality
How
will forests fare during
during heat waves and
droughts? This is an urgent
question because healthy
forests are important carbon
sinks, but when trees die they
become a carbon source.
Forests also transpire 40% of
the global average
precipitation falling on land
areas, which makes forests
integral to Earth's water
cycle and land-atmosphere
energy balance. Our research
products on tree mortality
include:
We also
examine the fate of trees through
the lens of root water uptake depth.
Scientists have long sought to
overcome their inability to peer
into the subsurface to see how root
processes interact with other
processes occurring below ground. We
developed a novel
modeling approach that provides
one "lens" for seeing below the
surface. We ask how does root
growth prior to and during drought
allow trees to adjust their water
uptake depths to sustain their
access reliable water sources? Here you can read
about our findings so far:
We are also
advancing new knowledge on how
lateral subsurface flow and
saturated soil zones mediate
tree health. Subsurface
hydrology has received less
attention than aboveground
processes for predicting the
physiological responses of
plants to drought. Our
work fills this gap by
considering the integrated
systems of plant hydraulics and
groundwater hydrology. Here you can
read about our findings so far:
We are
also examining how biotic
and other disturbances
combine with drought to
exacerbate forest decline
and the consequences for
water resources. These
disturbances are an
integral part of whole
ecosystems responses to
environmental dynamics,
but their roles in
integrated systems remains
only partly known. Here you
can read about our
findings so far:
We also
study how plant traits
interact with
environmental conditions
to influence plant growth
and productivity. By
examining these
interactions using crop
species and biophysical
process-based models, we
are improving
understanding of
mechanisms by manipulating
both plant traits and
environment. This enables
us to use a robust
hypothesis testing
framework to study traits
that are transferable to
natural settings and novel
environmental conditions.
Here you
can read about our
findings so far:
We have
long-term work on
sorting out biological
and physical controls
over evapotranspiration,
the largest path taken
by precipitation once it
falls on land areas. We
have asked how species,
plant age, disturbance,
and spatial gradients
associated with edaphic,
topographic, and
micrometeorologic
dynamics affect
evapotranspiration. Our
findings from this
work provided the
empirical and
theoretical foundation
for the Terrestrial
Regional Ecosystem
Exchange Simulator
(TREES), a globally
recognized biophysical
process-based model
for understanding
plant ecophysiological
responses to
environmental stress.
Here you can read
about our findings so
far:
