Humidity and Summer Precipitation Dynamics Recorded in Tree Rings

Verville, Julia; Ehleringer, James

Southwestern ecosystems currently experience high interannual variability in precipitation, and this variability is expected to increase under many global change scenarios. Due to the economic importance and carbon storage potential of forests, there is a great deal of interest in determining the response of forest ecosystems to global change factors such as increased atmospheric CO2, nitrogen deposition, and changes in temperature and precipitation. Like other ecosysmte sof the southwestern US forest systems are sensitive to moisture availability and are likely to be more sensitive to changes in precipitation than other climate change factors. As a result, understanding forest responses to future precipitation variability is essential to predicting forest responses to future precipitation regimes. Unfortunately, the size and longevity of forest trees impose severe constraints on the scope of monitoring and manipulative studies, limiting our understanding of how mature trees respond to environmental change. By using a combination of stable isotope techniques and traditional dendrochronology, we can establish long-term records of interannual climate variability and the physiological and growth responses of forest trees to climate and increasing atmospheric CO2 concentration.