Major%20Objectives

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Major Objectives

• (McIntire-Stennis, 1997-2001 2 graduate
  students)
• Initiated spatial measurements and geostatistical
  analysis of LAI and NPP
• (NASA Land Surface Hydrology, 1999-2003
  3 graduate students, 1 post-doc)
• Implications of converting forests from one
  species to another
• Implications for scaling up to landscapes
• Inter-annual variability
• (NSF Hydrologic Sciences, 2004-2007
  3 graduate students)
• Quantifying spatial gradients
• Carbon vs hydraulic limits to stomatal
  conductance
• Building simple, yet mechanistically more
  realistic models

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Chequamegon Ecosystem-Atmosphere Study(ChEAS)
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Burrows et al., 2002, Ecosystems
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Burrows et al., 2002, Ecosystems
Mackay et al., 2002, Global Change Biology
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Taxonomy of vegetation details
IGBP
IGBP
Site
-
Specific
Sap
-
Flux
Site
-
Specific
Sap
-
Flux
Classification
Classification
Classification
Species
Classification
Species
Mixed forest
Mixed forest
Forested wetland
Alder
Forested wetland
Alder
Mixed
Mixed
Cedar
Cedar
Wetland fir
Wetland fir
Deciduous broadleaf forest
Aspen
Deciduous broadleaf forest
Aspen
Aspen
Aspen
Upland fir
Upland fir
Hardwoods
Sugar maple
Hardwoods
Sugar maple
Basswood
Basswood
Evergreen
needleleaf
forest
Red pine
Red pine
forest
Red pine
Red pine
Jack pine
Jack pine
Upland conifer
Upland conifer
Open
shrublands
shrublands
Grass/Disturbed
Grass/Disturbed
Permanent wetlands
Permanent wetlands
Nonforested
wetland
Mackay et al., 2002, Global Change Biology
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Whole canopy transpiration
Ewers et al., 2002, Water Resources Research
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Landscape scale water fluxes
Average annual precipitation 800 mm Growing
season precipitation 300-500 mm Growing season
evapotranspiration 350-450 mm Canopy
transpiration (forest) 150-200 mm Canopy
transpiration (aspen) 300 mm
Mackay et al., 2002, Global Change Biology
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Effects of taxonomic aggregation
Total Evapotranspiration
Forest Transpiration
Biome-based models
Mackay et al., 2002, Global Change Biology
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Simpler, species-specific empirical models
Mackay et al., 2003, Advances in Water Resources
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Many different models meet the conditions
for calibration gt highly non-specific
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A more informed model identification
Efficient
Safe
Mackay et al., 2003, Advances in Water Resources
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Informed models are potentially scalable
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Ewers et al., 2006, Ag. For. Met.
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Ewers et al., 2006, Ag. For. Met.
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Ewers et al., 2006, Ag. For. Met.
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Ewers et al., 2006, Ag. For. Met.
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Ewers et al., 2006, Tree Physiology
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Plants will prevent hydraulic failure
(Oren et al., 1999)
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Spatial Gradient Approach
GSref f(L, edge distance, wetland distance) m
0.6GSref
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What if we increase edge effects?
Center-of-Stand Basis
Spatial Gradient Basis
Transpiration mm (30-min) 1
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Future Directions

• Phenology proposal (NSF ?)
• NSF Carbon/Water ?
• Forest manipulation (USDA ?)
• Continental scale, multi-tower inter-comparison
  (NASA ?)

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Publications

• Ewers, B.E., D.S. Mackay, and S. Samanta. 2006.
  Interannual consistency in canopy stomatal
  conductance control of leaf water potential
  across seven tree species. Tree Physiology, in
  press.
• Ewers, B.E., D.S. Mackay, J. Tang, P. Bolstad,
  and S. Samanta. 2006. Intercomparison of Sugar
  Maple (Acer saccharum Marsh.) stand transpiration
  responses to environmental conditions from the
  Western Great Lakes Region of the United State.
  Agricultural and Forest Meteorology, in press.
• Ahl, D.E., Gower, S.T., Mackay, D.S., Burrows,
  S.N., Norman, J.M., and Diak, G. 2005. The
  effects of aggregated land cover data on
  estimating NPP in northern Wisconsin. Remote
  Sensing of Environment, 97, 1-14.
• Ahl, D.E., S.T. Gower, D.S. Mackay, S.N.
  Burrows, J.M. Norman, and G.R. Diak. 2004.
  Heterogeneity of light use efficiency in a
  northern Wisconsin forest implications for
  modeling net primary production with remote
  sensing. Remote Sensing of Environment, 93,
  168-178.
• Burrows, S.N., S.T. Gower, J.M. Norman, G. Diak,
  D.S. Mackay, D.E. Ahl, and M.K. Clayton. 2003.
  Spatial variability of aboveground net primary
  productivity for a forested landscape in northern
  Wisconsin. Canadian Journal of Forest Research,
  33, 2007-2018.
• Mackay, D.S., D.E. Ahl, B.E. Ewers, S.
  Samanta, S.T. Gower, and S.N. Burrows. 2003.
  Physiological tradeoffs in the parameterization
  of a model of canopy transpiration. Advances in
  Water Resources, 26(2), 179-194.
• Mackay, D.S., S. Samanta, D.E. Ahl, B.E.
  Ewers, S.T. Gower, and S.N. Burrows. 2003.
  Automated parameterization of land surface
  process models using fuzzy logic. Transactions in
  GIS, 7(1), 139-153.
• Mackay, D.S., D.E. Ahl, B.E. Ewers, S.T. Gower,
  S.N. Burrows, S. Samanta, and K.J. Davis. 2002.
  Effects of aggregated classifications of forest
  composition on estimates of evapotranspiration in
  a northern Wisconsin forest. Global Change
  Biology, 8(12), 1253-1265.
• Burrows, S.N., S.T. Gower, M.K. Clayton, D.S.
  Mackay, D.E. Ahl, J.M. Norman, and G. Diak.
  2002. Application of geostatistics to
  characterize LAI for flux towers to landscapes.
  Ecosystems, 5(7), 667-679.
• Ewers, B.E., D.S. Mackay, S.T. Gower, D.E. Ahl,
  S.N. Burrows, S. Samanta. 2002. Tree species
  effects on stand transpiration in northern
  Wisconsin. Water Resources Research, 38(7),
  10.1029/2001WR000830.

Downloadable from http//water.geog.buffalo.edu/ma
ckay/pubs
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