Finding climatologically teleconnected sites with a network of tree ring chronologies

We need information about the past to understand what is happening in the present and to predict what may happen in the future. Trees record climate conditions in their annual growth rings throughout their lives, providing us with centuries of valuable paleoclimate data. In addition to reconstructing climate records, dendrochronologists use tree rings to reconstruct the records of climate-driven phenomena, such as hydrological variables, prior to the start of instrumental records. Reconstruction models are improved with the inclusion of multiple tree species and multiple sites, which act as predictors of climatological and hydrological variables. I identified tree ring chronologies within 100km of the North Fork Nooksack watershed that co-vary with climate and hydrological conditions within the watershed. These chronologies are of various species, most of which do not grow inside the watershed. These trees react to the same large-scale climate fluctuations that occur within the watershed and drive its hydrological processes. Each chronology shows sensitivity to unique combinations of climate variables, capturing a wide range of climate conditions. Chronologies were detrended with a 50-year spline to remove age-related growth patterns, making them comparable across individual cores, sites, and species. The detrended chronologies, as unitless ring-width indices, were tested for correlation with monthly, seasonal, and annual climate variables from 1901-2009. These results are an initial step in the reconstruction of Sholes Glacier mass balance and North Fork Nooksack August streamflow. Without the addition of chronologies outside of the watershed, reconstruction models would be limited to a maximum of two tree species from six sites. The chronologies I find here will be used in my reconstruction models, improving the quality of my reconstructed records. In addition, this research provides insight into the relationship between climate fluctuations and the growth patterns of multiple tree species in the North Cascades region.