Dr. Ashley M. Matheny Department of Geological Sciences ...Jackson School of Geosciences Department...
Transcript of Dr. Ashley M. Matheny Department of Geological Sciences ...Jackson School of Geosciences Department...
Department of Geological SciencesJackson School of Geosciences
The theoretical basis for tree hydraulics
Dr. Ashley M. MathenyDepartment of Geological Sciences
University of Texas at Austin
Keck Institute for Space StudiesSensing Forest Water Dynamics From Space: Towards Predicting the Earth
System Response to Droughts October 14-18. 2019
Department of Geological SciencesJackson School of Geosciences
Nevada.usgs.gov
Vegetation-atmosphere feedbacks
Below ground processes
Atmospheric processes
Vegetation
C H2O
Department of Geological SciencesJackson School of Geosciences
Sap leaks from a birch tree during sensor installation in real time
How much water is flowing?
Department of Geological SciencesJackson School of Geosciences
Water transport: the basics
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Water movement inside of a plant
From Bohrer et al 2005, WRR
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The onset of hydraulic limitations
From Brodribb et al. 2015, New Phytologist
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Cavitation and hydraulic vulnerability
From Maherali et al. 2006, PC&E
Xylem water potential (-Mpa)
Perc
ent l
oss c
ondu
ctiv
ity
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Trading safety for efficiency?
• A perfect tradeoff of safety and efficiency doesn’t exist (Gleason 2016, New Phytologist), because compounding variables abound
From Manzoni 2013, New Phytologist
Xylem water potential gradient @ max transpiration
Xyl
em h
ydra
ulic
con
duct
ance
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Trading carbon for water:Carbon maximization theory
Max
xyl
em te
nsio
n ef
ficie
ncy
From Anderegg et al. 2018, Ecology Letters
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Day of year
Sap
flow
(g m
-2s-1
)
Soil
moi
stur
e (%
)
Prec
ipita
tion
(mm
)Consequences of hydraulic strategies
Matheny et al. 2017, Ecohydrology
“Mini drought”
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Diurnal leaf water dynamics
Red oakRed maple
Pre-
daw
n Ψ
L (b
ar)
Mid
-day
ΨL
(bar
)
Soil moisture (%) Soil moisture (%)
Thomsen et al. 2013, Forests
*Note: 10 bar = 1 MPaMeasuring leaf water potential with Alyssa Wunderlich (REU), summer 2014
N.S.
N.S.
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Reliance on biomass capacitance
Matheny et al. 2015, Ecosphere
“Mini drought”
Stor
age
(kg)
Soil
wat
er c
onte
nt (m
3 m-3
)
OakMapleSoil water content
Stor
age
(kg)
Soil
wat
er c
onte
nt (m
3 m-3
)Capacitance sensor in maple, 2016
Day of year
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Maple
R2 = 0.53P < 0.0001
Water storage dynamics with declining soil water
WETDRY
Diu
rnal
wat
er w
ithdr
awal
(kg)
Soil water potential (MPa)
Department of Geologic SciencesJackson School of Geosciences
Differential access to water in the root-zone
• D-excess:δD-8* δ18O
Matheny et al. 2016, Ecohydrology
δ2 H (‰
VSM
OW
)
δ18O (‰ VSMOW)
(+) d-excess
(-) d-excess
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The framework for a whole plant hydraulic strategy
McCulloh et al. 2019, PCE
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Isohydricity as a whole plant response
Martinez-Vilalta & Garcia-Forner 2017, PCE
Department of Geological SciencesJackson School of Geosciences
Isohydricity as a whole plant response
McCulloh et al. 2019, PCE
Novick et al. 2019, PCE
= + +
= +
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Can we classify species based on hydraulics?
Meinzer et al. 2016, Ecology Letters
Blue Oak Scouler’s Willow
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Correlations among hydraulic traits?
Fu et al. 2019, PCE Hydroscape area
Stem
Cap
acita
nce
(kg
m-3
MPa
-1)
Leaf
Cap
acita
nce
(kg
m-3
MPa
-1)
Leaf
hyd
raul
ic
cond
ucta
nce
(mm
olm
-2M
Pa-1
)
Stem
hydr
aulic
co
nduc
tivity
(kg
m-1
s-1M
Pa-1
)
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Hydraulic “trait spaces”
Mursinna, et al. Forests 2018
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Its not just about depth anymore Underrepresented parameters: Roots
Agee, et al. In prep
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Hydraulic strategy influences growth
Matheny et al. 2017, Ecohydrology
• 2001-2014• Maple: n = 423• Oak: n = 114
Dendrometer (Saskatchewan)
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Changes to canopy structure and composition
Disturbance
Leaf
are
a in
dex
(m2
m-2
)
Control
• Control LAI ≈ 3.89 m2m-2
• Disturbance LAI ≈ 3.68 m2m-2
Department of Geological SciencesJackson School of Geosciences
Water limitation produces largest plot-scale differences
WETDRY
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Within ecosystem divergent hydraulic function is common!
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The difficulties of scale
Can we connect hyper-local measurement to big-picture understandings of ecosystems?
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Scaling from tree to ecosystem level
DBH (cm)
Control Disturbance
• Trees within the same histogram ‘bin’ are assumed to transpire similarly.
Multispectral imagery of UMBS
Aerial LiDAR of UMBS
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Scaling from tree to ecosystem level
Sap flux Latent heatTota
l sea
sona
l flu
x (W
m-2
grou
nd)
Control
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Intra-specific trait variation
Anderegg 2015, New Phytologist
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How does drought effect the trees that live?
New challenges
Bohrer, et al. AGU 2018
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Hysteretic responses to water stress
Bohrer, et al. AGU 2018
Department of Geological SciencesJackson School of Geosciences
A deeper perspective on xylem networks
Mrad, et al. 2018 PCE
Department of Geological SciencesJackson School of Geosciences
Acknowledgements
Gil Bohrer, Peter Curtis, Liz AgeeRich Fiorella, Chris Vogel, Tim Morin, Camilo Rey-Sanchez, Alyssa Wunderlich,Valeriy Ivanov, Karina Schäfer, Chris Gough, Luke Nave, Julia Thomsen, Golnaz Mirfenderesgi, Ana Maria Restrepo Acevedo, Austin Rechner, A. Rio Mursinna, Airborne LiDAR – NCALM (UMBS data)P.E.O. Chapter AV
Department of Geological SciencesJackson School of Geosciences
Vegetation plays a central role in water, energy, and nutrient cycles
Plants control hydraulic function dynamically!
New measurements and models can improve our understanding of hydrosphere-biosphere-atmosphere exchange