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A Water Use Efficiency History of Siberian Scots Pine Trees
Arneth, A., Lloyd, J., Santruckova, H., Bird, M., Grigoryev, S., Kalaschnikov, Y.N., Gleixner, G. and Schulze, E.-D.  2002.  Response of central Siberian Scots pine to soil water deficit and long-term trends in atmospheric CO2 concentration.  Global Biogeochemical Cycles 16: 10.1029/2000GB001374.

What was done
The authors developed twenty tree-ring 13C/12C chronologies from Pinus sylvestris (Scots pine) trees at five locations along a 1000-km north-south transect running through central Siberia that they converted into plant isotopic discrimination values (delta13Cc).

What was learned
In the words of the authors, "in 17 of the 20 samples, [the] trees' delta13Cc has declined during the last 150 years, particularly so during the second half of the twentieth century."  Based on a model of stomatal behavior combined with a process-oriented photosynthesis model, they deduced that "this trend indicates a long-term decrease in canopy stomatal conductance, probably in response to increasing atmospheric CO2 concentrations."

What it means
The authors conclude that their observations are suggestive of "increased water use efficiency for Scots pine in central Siberia over the last century," which indicates that life there has gotten a bit easier in recent years ... especially for trees.

Reviewed 8 January 2003