The Effects of Climate on Radial Growth of Disjunct Northern White Cedar (Thuja occidentalis L.) in Virginia

Understanding the geographic range and growth of species is essential for effective land management in a landscape affected by anthropogenic activity and climate change. Climate change is expected to alter the distribution and growth of many tree species in eastern North America, including northern white cedar (Thuja occidentalis L.). This research examined the effects of climate on radial growth of T. occidentalis in disjunct populations south of its continuous range margin in eastern North America. A T. occidentalis tree-ring chronology was developed and examined for growth-climate interactions. Mean sensitivity of the T. occidentalis chronology was within the range of values reported for the species in northern portions of its range. Significant positive correlations existed between the T. occidentalis chronology and moisture variables late in the growing season of the previous year and current year. The relationship between the T. occidentalis chronology and temperature was more variable with significant positive and negative correlations throughout the previous year and current year. The Ordinary Least Squares (OLS) regression model suggested moisture conditions late in the growing season of the previous year and current year had a significant positive influence on the growth of T. occidentalis. In contrast, maximum temperature in March of the current year negatively influenced the growth of T. occidentalis. While the mean sensitivity of T. occidentalis appears similar throughout its range, there is geographic variability in the climate-growth response of T. occidentalis. More research is necessary to expand the scope of our knowledge concerning T. occidentalis growth throughout its range.