CLIMATE-RADIAL GROWTH RELATIONSHIPS OF NORTHERN LATITUDINAL RANGE MARGIN LONGLEAF PINE (PINUS PALUSTRIS P. MILL.) IN THE ATLANTIC COASTAL PLAIN OF SOUTHEASTERN VIRGINIA

Climate and longleaf pine (Pinus palustris P. Mill.) radial growth relationships have been documented within its southern and western distribution. However, knowledge of this relationship is lacking along its northern latitudinal range margin (NLRM). Based on the principles of ecological amplitude, limiting factors, and studies of coniferous species in eastern temperate forests of the U.S., we hypothesized that the radial growth of longleaf Pine in mixed pine-hardwood forests is responding to winter temperatures in southeastern Virginia. Two longleaf pine chronologies were developed to determine the relationship between radial growth and monthly temperature, precipitation, and Palmer Drought Severity Index (PDSI) via response function analysis (REA). Results at the 0.05 level yielded significant response function coefficients with a positive response to current winter temperature and precipitation and a negative response to prior August PDSI. In studies of climate and longleaf pine radial growth in other parts of its range, winter temperature and precipitation have not shared a significant positive association with radial growth. Instead current spring and summer precipitation usually share this positive association. These findings add more evidence to an emerging pattern suggesting that winter temperatures contribute to limiting the radial growth of temperate conifers at northern range margins in the Northern Hemisphere.