The graph (above) demonstrates the difference between moist and dry sites. Silvertip is at tree line and is a moist location. Growth is limited by temperature and shows cooler 1800's and recent warming. The Cub Creek site is about 100m below tree line and is an edaphic desert. The trees grew best during two cooler, wetter intervals during the mid 1800's, initially responding to warmer temperatures in the 1930s and 1940s, but are now in serious decline with recent warmer temperatures and increasing evapotranspiration.