ORIGINAL PAPER Influence of climate and disturbance on the growth of Tsuga canadensis at its southern limit in eastern North America Justin L. Hart • Saskia L. van de Gevel • John Sakulich • Henri D. Grissino-Mayer Received: 24 June 2009 / Revised: 10 February 2010 / Accepted: 15 March 2010 / Published online: 1 April 2010 Ó Springer-Verlag 2010 Abstract It has long been hypothesized that trees grow- ing at range limits likely also occur near the limit of their ecological amplitude and thus, should be more sensitive to climate variability than individuals growing nearer the range core. We developed a tree-ring chronology using Tsuga canadensis individuals from three disjunct stands at the species’ southern limit to quantify the influence of climate and disturbance on radial growth patterns. The tree-ring record extended 158 years from 1850 to 2007. Significant negative relationships were found between the STANDARD chronology and monthly mean temperature, monthly maximum temperature, and monthly minimum temperature during the previous and current summer, while significant positive relationships were documented between the STANDARD chronology and monthly minimum tem- perature for September and October of the current year. Also, significant positive relationships were documented between the STANDARD chronology and monthly total precipitation for September of the previous year and May of the current year. Response function analysis showed that monthly climate variables (r 2 = 0.22) and prior growth (r 2 = 0.40) explained 62% of the variance in the T. canadensis tree-ring chronology. A time series plot for the T. canadensis chronology showed that actual tree growth agreed relatively well with the predicted growth based on significant climate variables. However, positive departures from the predicted growth were noted. Den- droecological analysis revealed these departures were likely related to disturbance events. Our results indicated that T. canadensis individuals at its southernmost extent are sensitive to regional climate, but not more so than trees nearer the range core. We hypothesize that microenviron- mental conditions of T. canadensis stands at its southern limit are similar to conditions within the contiguous dis- tribution of the species, which may explain this pattern. Keywords Tsuga canadensis Á Dendrochronology Á Ecological amplitude Á Climate Á Biogeography Introduction Ecological amplitude is defined as the variety of environ- mental conditions within which a species may grow and reproduce (Fritts 1976). Species that only live and function on restricted sites have a narrow ecological amplitude, while species that occur over a range of different habitats have a wide ecological amplitude. In the field of dendro- chronology, ecological amplitude is used as a guiding principle as trees most useful for the analysis of climatic influences on annual growth patterns often occur near the margins of their natural range (Fritts 1976). In theory, individuals near range margins are more sensitive to environmental conditions such as climate. Thus, mean sensitivity (i.e. year-to-year variation in growth) should be high and annual growth patterns of trees within peripheral populations should be consistent (Fritts and Swetnam Communicated by S. Leavitt. J. L. Hart (&) Department of Geography, University of Alabama, Tuscaloosa, AL 35487, USA e-mail: hart013@bama.ua.edu S. L. van de Gevel Department of Geography and Planning, Appalachian State University, Boone, NC 28608, USA J. Sakulich Á H. D. Grissino-Mayer Department of Geography, University of Tennessee, Knoxville, TN 37996, USA 123 Trees (2010) 24:621–633 DOI 10.1007/s00468-010-0432-y