Comparison of climate–growth responses of montane and piedmont longleaf pine (Pinus palustris Mill.) chronologies in North Carolina

Abstract

Montane longleaf pine tree-ring chronologies exhibit fidelity to summer soil-moisture conditions. Multi-century climate reconstructions using longleaf pine can provide insights into the natural range of moisture variability. Longleaf pine (Pinus palustris Mill.) ring width is associated with temperature and precipitation throughout its range, yet intrasite comparisons of climate and ring growth are limited and have not examined interior (i.e., montane vs. piedmont) populations. Here, we investigated remnant stands of montane and piedmont longleaf pine in central North Carolina and compared their sensitivity to summer climatic variables during 1935–2015. Summer precipitation and PDSI were better associated with tree-ring chronologies developed from latewood growth from both the montane (r = 0.429 PDSI, r = 0.563 precipitation) and piedmont (r = 0.252, r = 0.441) chronologies while correlations with temperature variables were either weak (r = − 0.249 maximum temperature montane, r = − 0.229 piedmont) or not significant. We examined longleaf pine latewood sensitivity to late-summer (July–September) climate conditions, drought detection, and differences in radial growth during drought and non-drought periods and found greater sensitivity of the montane chronology to these metrics. Specifically, the montane chronology was more sensitive to drought detection identifying all 11 droughts that occurred during the 81-year study period, while the piedmont chronology identified only 6 of the 11. Further, while significant differences in radial growth existed between drought and non-drought years for both chronologies, the montane chronology exhibited considerably greater growth range between these favorable and unfavorable periods. These results indicate the use of montane longleaf pine is preferable when reconstructing precipitation variability and when coupled with remnant stump data provide an opportunity to reconstruct summer climate variability.