Preliminary Observations of Water

1
Preliminary Observations of Water Carbon
DioxideFluxes Across anAlpine Treeline

• Peter Blanken, Mark Williams
• Department of Geography, University of Colorado,
  Boulder, Colorado
• Russ Monson, Sean Burns
• Department of Ecology and Evolutionary Biology,
• University of Colorado, Boulder, Colorado
• Kurt Chowanski, Todd Ackerman
• INSTAAR, University of Colorado, Boulder,
  Colorado
• John Knowles, Adriana Bailey
• Department of Geography, University of Colorado,
  Boulder, Colorado

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Introduction Background Sites Methods
Results Summary

• goals and objectives

• Can eddy covariance (plot-scale) measurements be
  made in complex terrain (1/3 cont. US)?
• Determine the magnitude/behavior of water/carbon
  cycling in two important alpine ecosystems
  (alpine tundra subalpine forest).
• Compare/contrast the differences dynamics of
  water/carbon cycling across the alpine treeline.

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Introduction Background Sites Methods
Results Summary

• observed changes at treeline

• Changes in species composition
• (e.g. Keller et al. 2000 Pauli et al. 2001
  Walther et al. 2005)
• Increased growth rates
• (e.g. Paulson et al. 2000 Motta Nola 2001)
• Increased tree
• establishment
• (e.g. Körner 2003)
• Changes in land
• use and climate
• (e.g. Beniston et al. 1997
• Gehrig-Fasel et al. 2007)

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Introduction Background Sites Methods
Results Summary

• causes climate

• Major climate shifts?
• European Alps
• 2 oC increase annual min. temps. last century
  (Beniston et al. 1997)
• Swiss Alps
• 2.5 oC increase
• mean annual temp.
• last century
• (Gehrig-Fasel et al. 2007)

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Introduction Background Sites Methods
Results Summary

• causes land use

• Major changes in land use?
• Swiss Alps Alpine farming decreased considerably
  since mid 19th century
• (Mather Fairbairn 2000)
• Rocky Mountains
• urbanization
• pollution fire
• suppression
• logging mining
• mtn. pine beetle

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Introduction Background Sites Methods
Results Summary

• causes land use climate

Western Italian Alps (Motta et al. 2006) .tree
establishment, and more in general the forest
dynamic, has been mainly controlled by human
land-use and that the tree growth has been mainly
climatically controlled. Swiss Alps
(Gehrig-Fasel et al., 2007) 90 new forest was
invasion into abandoned grasslands 10 true
upward shifts of local treeline (4 attributed to
recent climate warming)
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Introduction Background Sites Methods
Results Summary

• location

Tundra
3.8 km
Forest
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Introduction Background Sites Methods
Results Summary

• alpine tundra

• Elevation 3523 m asl
• Relatively flat ridge
• High solar radiation
• Low air temps. (-3.7 oC mean annual at 3743 m)
• Mean annual P 930 mm, most as snow
• Sparse, low vegn
• LAI lt 1 (lt 0.5?)

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Introduction Background Sites Methods
Results Summary

• subalpine forest

• Elevation 3050 m asl
• 2 km east of treeline
• average annual P 800 mm
• Mean annual air temp 4 oC
• Subalpine fir, Engelmann spruce, lodgepole pine
• LAI 4.2

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Introduction Background Sites Methods
Results Summary

• eddy covariance

High-frequency vertical wind speed (w), H2O /
CO2 density (scalar s). Covariance of deviation
(') from 30-min means (-). Std. corrections.
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Introduction Background Sites Methods
Results Summary

• energy balance closure

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Introduction Background Sites Methods
Results Summary

• General meteorology
• air temperature

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Introduction Background Sites Methods
Results Summary

• General meteorology
• relative humidity

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Introduction Background Sites Methods
Results Summary

• General meteorology
• horizontal wind
• speed

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Introduction Background Sites Methods
Results Summary

• General meteorology
• wind direction

Night
Day
Tundra
Forest
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Introduction Background Sites Methods
Results Summary

• Non-turbulent fluxes
• net radiation

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Introduction Background Sites Methods
Results Summary

• Turbulent fluxes
• sensible heat flux

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Introduction Background Sites Methods
Results Summary

• Turbulent fluxes
• latent heat flux

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Introduction Background Sites Methods
Results Summary

• Turbulent fluxes
• evaporative fraction

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Introduction Background Sites Methods
Results Summary

• cumulative evaporative
• water loss

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Introduction Background Sites Methods
Results Summary

• Turbulent fluxes
• CO2 flux

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Introduction Background Sites Methods
Results Summary

• Turbulent fluxes
• CO2 flux

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Introduction Background Sites Methods
Results Summary

• cumulative carbon
• surface gain

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Introduction Background Sites Methods
Results Summary

• correlations

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Introduction Background Sites Methods
Results Summary
The tundra ___ is ___ than that at the forest

• comparisons

26
Preliminary Observations of Water Carbon
DioxideFluxes Across anAlpine Treeline
Peter Blanken, Mark Williams Department of
Geography, University of Colorado, Boulder,
Colorado Russ Monson, Sean Burns Department of
Ecology and Evolutionary Biology, University of
Colorado, Boulder, Colorado Kurt Chowanski, Todd
Ackerman INSTAAR, University of Colorado,
Boulder, Colorado John Knowles, Adriana
Bailey Department of Geography, University of
Colorado, Boulder, Colorado
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References

• Beniston, M., Diaz, H.F. Bradley, R.S. 1997.
  Climatic change at high elevation sites An
  overview. Clim. Change 36 233-251.
• Bolli, JC, Rigling A, Bugmann H. 2007. The
  influence of changes in climate and land-use on
  regeneration dynamics of Norway Spruce at the
  treeline in the Swiss Alps. Silva Fennica 41(1)
  55-70.
• Gehrig-Fasel J , Guisan A, Zimmermann NE. 2007.
  Tree line shifts in the Swiss Alps Climate
  change or land abandonment? J. Veg. Sci., 18(4),
  571-582.
• Keller, F., Kienast, F. Beniston, M. 2000.
  Evidence of response of vegetation to
  environmental change on high-elevation sites in
  the Swiss Alps. Reg. Environ. Change 1 70-77.
• Körner, C. 2003. Alpine plant life Functional
  plant ecology of High Mountain ecosystems. 2nd.
  ed. Springer, Berlin- Heidelberg, DE.
• Motta R, Morales M, Nola P 2006 Human land-se,
  forest dynamics and tree growth at the treeline
  in the Western Italian Alps. Annals of Forest
  Science, 63(7) 739-747.
• Mather, A.S. Fairbairn, J. 2000. From floods to
  reforestationThe Forest Transition in
  Switzerland. Environ. History 6399-421.
• Motta, R. Nola, P. 2001. Growth trends and
  dynamics in subalpine forest stands in the
  Varaita Valley (Piedmont, Italy) and their
  relationships with human activities and global
  change. J. Veg. Sci. 12 219-230.

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References

• Pauli, H., Gottfried, M. Grabherr, G. 2001.
  High summits of the Alps in a changing climate.
  The oldest observation series on high mountain
  plant diversity in Europe. In Walther, G.R.,
  Burga, C.A. Edwards, P.J. (eds.) Fingerprints
  of climate change. Adapted behaviour and shifting
  species ranges, pp. 139-149. Kluwer
  Academic/Plenum Publishers, NY, US.
• Paulsen, J., Weber, U.M. Körner, C. 2000. Tree
  growth near tree line Abrupt or gradual
  reduction with altitude? Arct. Antarct. Alp. Res.
  32 14-20.
• Walther, G.-R., Beissner, S. Burga, C.A. 2005.
  Trends in the upward shift of alpine plants. J.
  Veg. Sci. 16 541-548.

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Extras.
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Introduction Background Sites Methods
Results Summary

• causes land use climate

• Swiss Alps (Gehrig-Fasel et al., 2007)
• 90 new forests ingrowth (invasion into abandoned
  grasslands) 10 true upward shifts of local
  treeline
• Small fraction (4) attributed to recent climate
  warming (but likely
• to increase)
• Land abandonment
• most dominant
• driver

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Introduction Background Sites Methods
Results Summary

• causes land use climate

Western Italian Alps (Motta et al. 2006) An
analysis of all the data taken together in the
present study argues in favor of the fact that
the tree establishment, and more in general the
forest dynamic, has been mainly controlled by
human land-use and that the tree growth has
been mainly climatically controlled. (dendroecol
ogical methods,1850-present)
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Introduction Background Sites Methods
Results Summary

• summary

• Two anthropogenic disturbances closely related to
  changes in treeline ecotones
• Land use changes
• Rapid climate change
• Combination of both
• Warming agriculture
• abandonment (e.g.
• Swiss Alps
• (Bolli et al. 2007)

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Introduction Background Sites Methods
Results Summary

• location

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Introduction Background Sites Methods
Results Summary

• Non-turbulent fluxes
• ground heat flux