A dendroclimatic comparison of summertime moisture sensitivity of Chestnut Oak with four co-occurring pine species in the Southeastern United States

We investigated the climate-growth responses of chestnut oak and four co-occurring native pine species (longleaf, pitch, shortleaf, and Virginia) at two montane sites in central North Carolina, USA. Our study focused on species-specific climate/growth sensitivities to summertime seasonal precipitation and the Palmer Drought Severity Index (PDSI) from 1921–2020 based on adjusted latewood ring-width variability. At both sites, chestnut oak consistently exhibited the strongest correlations with early-to-mid-summer (i.e., May–July) precipitation and for nearly all summer months PDSI values. In contrast, the pine species showed preferences for mid- to-late summer precipitation with weaker associations with PDSI. From a dendroclimatological perspective, the use of chestnut oak is beneficial because: 1) it exhibits more stable climate-growth responses via fewer outlier values than co-occurring conifers, 2) it more closely approximates years with well-below or well-above soil moisture, 3), the low commercial value of the chestnut oak has limited logging potential, resulting in extensive populations of the species throughout the Southeastern United States, often with old-growth (> 150 years) individuals, and 4) the wide distribution of old-growth trees on easily accessible public lands provides an opportunity to examine/reconstruct climate variability at a comparatively greater spatial scale than the pine species.