Spatial Variability of Tree Growth in the Interior West
To test for possible controls on tree growth variability, individual tree-ring data from Forest Inventory and Analysis plots were paired with other plot-level data such as elevation, longitude and latitude. This analysis used almost 3,000 Douglas-fir, ponderosa pine, pinyon, and limber pine from Idaho, Montana, Wyoming, Utah, and Colorado, spanning 12 degrees of latitude, and 15 degrees of longitude.
Contrary to widely held beliefs, Forest Service researchers found no relationship between growth variability and elevation or latitude for all the species examined. There was a positive relationship found between growth variability and longitude, with more variability from west to east. The longitude relationship was largely driven by the presence of ponderosa pine and Douglas-fir in the easternmost forests of the Interior West.
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