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. Given all this, we seek to
know how plants thrive in stressful
environments?
To answer this question we seek an
improved understanding of the
connections between water resources
and plant ecophysiology. We seek to
predict plant responses to stress by
combining measured plant traits and
environmental conditions, and building
biophysical
process-based models to gain
mechanistic insight on hard to
observe plant processes. 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. Below our ongoing
projects and related products
demonstrate how we are new knowledge
on plant responses to environmental
stress.
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, land-atmosphere energy
balance, and production of
atmospheric oxygen.
We also
examine the fate of trees through
the lens of roots 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
have developed a novel
modeling approach that provides a
"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 advancing
new knowledge on how lateral
subsurface flow and saturated
soil zones mediate tree health.
Subsurface hydrology has
received relatively little
attention when considering the
physiological responses of
plants to drought. Our
work addresses this gap by
considering the integrated
systems of plant hydraulics and
groundwater hydrology. Here you can
read about our findings so far:
We are
examining how biotic and
other disturbances combine
with drought to exacerbate
forest decline and
consequent changes to
water resources. These
disturbances are an
integral part of whole
ecosystems responses to
environmental dynamics. 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 exploring 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 also
have ongoing work that
seeks new insights on
biological and physical
controls over
evapotranspiration,
which is the largest
path taken by
precipitation once it
falls on land areas. We
have asked how species,
plant age, disturbance,
and gradients associated
with edaphic,
topographic, and
micrometeorologic
dynamics affect
evapotranspiration, and
how the associated
mechanisms can be used
to build robust yet
transferable models. 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:
