Files
Abstract
Throughout the past century, there has been a global shift in climate. Temperatures have been rising, and while precipitation has been fluctuating, it has exhibited not obvious trends. This change in climate has led to global treeline advancement, and has presented ecological, economic, and social implications. Two of the most relevant implications, especially within the context of the western United States, are changing ecosystem dynamics and water yields. Therefore this study aims to explore the effects of climate change at treeline throughout the Colorado Rockies, with the objective to use simple meteorological data to explain and predict radial tree growth. Data was collected at ten individual mountains in five mountain ranges throughout the state. The subsequent dendrochronologies for each mountain were correlated with time, local and regional meteorology, and the other nine sites. The correlation between sites was compared to the distance between sites. Chronologies were also compared to regional wind and storm patterns. Ultimately, no significant climatic trends appeared to influence individual tree growth on a regional scale throughout the Colorado Rockies. In some sites, such as those bordering the western Colorado deserts, increasing precipitation led to increased radial growth. At a small number of sites in the Front Range and the Sawatch Range, increased summer and annual temperatures led to increased radial growth as well. The remaining sites showed no connection between radial tree growth and simple local and regional meteorological data. The dendrochronologies between most mountains were significantly correlated; the correlations ranged from 0.93 to 0.25, with most of the sites correlated at 0.6 and above. Surprisingly, the correlation coefficients between sites did not respond to the distance between mountains in a statistically significant way. Based on an analysis between site correlations, three groups emerged with inter-site correlation at 0.7 and above: west of the Continental Divide, Front Range and Central Rockies, and along the Continental Divide. In general, these groups showed a southwest to northeast orientation. Storm patterns that flow from the southwest to the northeast throughout the state act as the central variable in correlating chronologies between sites. Conclusively this study does not support the hypotheses that claim climate significantly affects radial growth, but instead provides important information that can be used to further understand the implications of climate on treeline dynamics in the Colorado Rockies.