Consequences Of Stand Age And Structure On Forest Water Yield
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Transcript of Consequences Of Stand Age And Structure On Forest Water Yield
Consequences Of Stand Age And Structure On Forest Water Yield
Chelcy Ford Miniat, Pete V. Caldwell, A. Chris Oishi, Katherine ElliottUSDA Forest Service, SRS, Coweeta Hydrologic Lab, Otto, NC
Steven T. BrantleyJoseph W. Jones Ecological Research Center, Newton, GA
Kim A. NovickUniversity of Indiana, School of Public and Environmental Affairs, Bloomington, IN
Paul V. BolstadUniversity of Minnesota, College of Food, Agriculture and Natural Resource Sciences,
Department of Forest Resources, St. Paul, MN
USDA FS SRS
USDA FS SRSCaldwell et al., 2014
• 81% Forested (24% Nat’l Forest)• 23 billion m3/yr• 588 intakes• 336 communities• 10.7 million served
(4.9 M get >20%)
The southern Appalachians: Headwaters for drinking water supply
EPA SDWIS; WaSSI model output
Leuzinger and Korner 2010, GCBLabat et al. 2004, AWRGedney et al. 2006, Nature
Large-scale patterns in streamflow
Simple Water Balance
Input (Pre)– Output (Ro)= Loss (ET)
Surface water supplies are increasingly vulnerable to drought.
Rainfall distribution is the main driver of runoff under future warmer, higher CO2 world in a temperate deciduous forest.
River discharge across the globe has been increasing at a rate of 2% for each 0.5°C increase in global temperature.
USDA FS SRS
Post-1960 trend
Attribution of Post-1960 trend in ET
Local patterns in streamflow
Locally in the southern Appalachians, we see the opposite of the global and N. American trend.
Discharge in reference watersheds at Coweeta Hydrologic Lab has been decreasing at a rate of 1.3% for each 0.5°C increase in temperature.
USDA FS SRS
Ford et al., 2011
Hypotheses
USDA FS SRS
Over time water yield (Q) in unmanaged forests of the southern Appalachians has decreased
Both climate (precipitation and potential ET) and species changes in evapotranspiration (ET) have contributed to the decline
Coweeta Basin
N
• Established 1934• 1626 ha Basin
Coweeta Basin
N
• Established 1934• 1626 ha Basin• 16 active weirs
Coweeta Basin
N
• Established 1934• 1626 ha Basin• 16 active weirs• 5 climate stations
Coweeta Basin
N
• Established 1934• 1626 ha Basin• 16 active weirs• 5 climate stations• 10 rain gauges
Coweeta Basin
N
• Established 1934• 1626 ha Basin• 16 active weirs• 5 climate stations• 10 rain gauges• 676 vegetation plots
Elliott and Vose 2011
Changing forest species composition
USDA FS SRS
Major Forest Disturbances
Elm
Spa
nwor
m (1
961)
Hurr
ican
es F
ranc
is &
Ivan
(200
4)
Maj
or F
lood
(196
4)
Fall
Cank
erw
orm
(196
9-19
77)
Maj
or D
roug
ht (1
984-
1988
) SPB
and
Oak
Mor
talit
y
Hem
lock
Woo
lly A
delg
id (2
003-
pres
ent)
Hurr
ican
e O
pal (
1995
)
1900 1950 2000
Drou
ght (
1999
-200
1) SP
B m
orta
lity
1850
Ches
tnut
blig
ht (1
928-
1938
)
Logg
ing
(late
180
0s-1
920s
)
Hom
este
ads a
nd G
razin
gN
ative
Am
eric
an u
se o
f Fire
Hurr
ican
e (1
835)
Drou
ght (
2006
-200
8)
USDA FS SRS
Control Watersheds at Coweeta
USDA FS SRS
Quantifying changes in annual Q
AutoRegressive Integrated Moving AverageTime Series Modeling
• Can account for:• autocorrelation (memory)• transfer functions can combine independent
series (e.g., Q~P, PET) • external perturbations affecting the time series
(interventions, e.g., species data)
• Akaike’s Information Criterion (AIC) for model selection
USDA FS SRS
Q has changed in low elevation watersheds
Low elevation High elevation
• For WS14 and WS18, Q decrease began in 1974, declined by 22% or 64mm/decade
Hypotheses
Over time water yield (Q) in unmanaged forests of the southern Appalachians has decreased
Both climate (precipitation and potential ET) and species changes in evapotranspiration (ET) have contributed to the decline
USDA FS SRS
Precipitation has not changed
Change in P 1938-1946+373 mm/decade (p=0.0835) Checking standard rain
gauge at CS01 (1952)
USDA FS SRS
PET has increased in recent years
USDA FS SRS
1938-1949-50 mm/decade
p=0.0463
1997-2013+46 mm/decade
p=0.0023
CS01 Evaporation Pan:Measured daily since 1936
ET initially declined, but has increased markedly since the 1980s
Low elevation High elevation
• Increase began in 1980-1999, increasing by 37-93 mm/decade
Elliott and Vose 2011
Changing forest species composition
USDA FS SRS
Water use varies by species
Ford et al., 2011; Vose and Ford, 2011
Diffuse porous and tracheid xylem
Ring porous xylem
Red mapleTulip poplarWhite pineHemlock
Red oakChestnut oak
Semi-ring porous xylem Hickory
Disturbance has shifted tree abundance and composition
• Residuals from a model predicting Q as a function of climate only (P and PET)
Climate can explain some of the changes in Q, but not all
Low elevation High elevation
• Residuals from a model predicting Q as a function of climate only (P and PET)
• Residuals from a model predicting Q as a function of climate (P and PET) and species change
Low elevation High elevation
These changes in forest structure and species composition may have decreased water yield by as much as 18% in a given year since the mid-1970s after accounting for climate.
Summary
• There have been changes in water yield (Q) in unmanaged forests of the southern Appalachians• Q increased 30-55% in low elevation watersheds from 1938-1970s• Q decreased 22% from early 1970s to 2013 in some low elevation
watersheds
• There have been changes in P and PET that explain some the changes in Q and ET
• Changes in forest species composition and structure also played a role on Q and ET• Significant interventions indicate changes in Q by up to 10%• Canopy interception increases with age• Shift to dominance of diffuse porous species
USGS gauge 03500000, Little Tennessee River at PrentissReference gage
How widespread are these changes?
Departures from 1960-1980 line of fit
USDA FS SRS
Caldwell et al., in prep
Dr. Steven Brantley, AFRI project post-doc, now permanent Eco-hydrologist at Joseph W. Jones Ecological Research Center
Training, Mentoring and Products
Changes in interception with forest age
USDA FS SRS
Brantley et al., in prep
This AFRI project has successfully trained and mentored 3 post-doctoral research scientists, 2 graduate students, and 1 undergraduate student
Brantley, S. T., M. Schulte, P. V. Bolstad, and C. F. Miniat. 2016. Equations for estimating biomass, foliage area and sapwood of small trees in the southern Appalachians. Forest Science 62: 414–421
Equations for estimating structural characteristics of mid-canopy trees and shrubs in the Southern Appalachians.
USDA FS SRS
Ms. Morgan Schulte, AFRI project undergraduate student
Dr. Kim Novick, FS/AFRI project post-doc, now faculty at University of Indiana Bloomington
USDA FS SRS
Novick, K. A., et al. (2013). Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparisons. Ag For Met, 181, 17-32.
Novick, K., Brantley, S., Miniat, C. F., Walker, J., & Vose, J. M. (2014). Inferring the contribution of advection to total ecosystem scalar fluxes over a tall forest in complex terrain. Ag For Met, 185, 1-13.
Dr. Chris Oishi, AFRI project post-doc, now permanent Ecologist with USDA Forest Service Coweeta Hydrologic Lab
ET flux from canopy and subcanopy across forest
ages forest age
USDA FS SRSOishi et al., in prep
Benson, M., Oishi, A.C., Miniat, C.F., Domec, J.-C., and Novick, K.A. “Climate and age influence on drought-induced cavitation vulnerability in eastern deciduous forests”Oral presentation, Ecological Society of America Annual Meeting Ft. Lauderdale, FL. August 7-12, 2016. Poster presentation, AmeriFlux Annual Meeting, Golden, Colorado, September 21-23, 2016
Safety Margin (P50 - ΨL)across chronosequence:
• LITU – juvenile stands in more mesic site are at highest risk for drought induced mortality.
• QUAL – mature species in more mesic site are at the highest risk for drought induced mortality
Mr. Michael Benson, AFRI project undergraduate, now a MS student with Novick at IU
Oishi, A.C., et al. "Baseliner: An open-source, interactive tool for processing sap flux data from thermal dissipation probes." SoftwareX (2016).
Dehnam, S.O., Oishi, A.C., Miniat, C.F., Brantley, S.T., Novick, K.A. “Tree water use dynamics across different sites and age classes in the Southern Appalachians”. Poster presentation, Ecological Society of America, Annual Meeting Ft. Lauderdale, FL. August 7-12, 2016.
Ms. Sander Denham, AFRI project post-MS student, now a PhD student with Novick at IU
USDA FS SRS
Special thanks to Chris Sobek, Charles Marshall, Neal Muldoon, and all scientists, technicians and students who have contributed to the long-term
dataset.
This project was supported by:
Agriculture and Food Research Initiative Competitive Grant number 2012-67019-19484 from the USDA National Institute of Food and
Agriculture
USDA FS SRS
USFS/UMN cooperative agreement (agreement #12-CS-11330140-128)
Acknowledgements