Large Scale Studies

On predicting the response of forests in eastern North America to future climatic change. Ed Cook & J. Cole. 1991. Climatic Change 19:271-282.

This study used 42 hemlock growth chronologies (4 in the HV watershed) to study the landscape pattern of the climatic response throughout its range.

One spatial pattern of correlation was with March temperatures & was centered on the Adirondack Mtns & the N end of the Hudson Valley (figure above).

This region lies at the convergence of the winter Arctic & Pacific Frontal Zones & is an important boundary between the permanently humid, warm summer (to the south) and subcontinental (to the north) climatic regions.

Tree rings as indicators of climate change and the potential response of forests to the greenhouse effect. Ed Cook. 1991. In Wyman, R.L., ed., Global Climate Change and Life on Earth. Routledge, Chapman and Hall, New York. pp. 56-64.

This study used 97 tree growth chronologies made up of 6 species throughout the eastern deciduous forest to create a large-scale eastern US growth record (figure below, C).

Drought index (A) and reconstructions (B) were then compared to the eastern US growth record (figure above).

 

It is clear that large-scale variations in tree growth are largely driven by drought.

Less well understood is the greenhouse gas climatic change effect on precipitation. Thus, changes in precipitation, not temperature seem to be the most important for eastern US forests.