Old-growth longleaf pine (Pinus palustris) is a keystone/foundation species for 29 threatened or endangered species in the Coastal Plain of the southeastern United States. The endangered red-cockaded woodpecker (Dryobates borealis; RCW) and endangered longleaf pine have an established ecological association. Here, we explore differences in climate/growth response and radial growth disturbance events in trees with RCW cavities compared to non-cavity trees in the Sandhills Gameland Reserve in North Carolina, USA. Using standard dendrochronological techniques, we collected and analyzed core samples from trees selected by RCW for their cavities (RCWC) and adjacent control trees (RCWCo) that had no visible cavity. We developed RCWC and RCWCo tree-ring chronologies that allowed us to examine if climate vulnerability is a component of the RCW selection process for their nests. Specifically, we investigated climate/growth responses, radial growth suppressions, and physical characteristics of both tree types through a comparison of tree age, latewood radial growth measurements, and number of resin ducts. For long-term climate response (1910-2018), we found no significant differences between RCWC and RCWCo trees. However, we identified temporal differences in climate/growth relationships between RCWC and RCWCo as well as significant differences in the number of suppression events and spatially-grouped suppression events. For tree physiology, we found more resin ducts during 1950-2018 in RCWC trees. Our dendroecological-based investigation examines multiple factors in addressing the question of why RCWs select specific longleaf pine trees for cavities, which may help improve conservation efforts for RCW and longleaf pine.

The longleaf pine ( Pinus palustris Mill.) and related ecosystem is an icon of the southeastern United States (US). Once covering an estimated 37 million ha from Texas to Florida to Virginia, the near-extirpation of, and subsequent restoration efforts for, the species has been well-documented over the past ca. 100 years. Although longleaf pine is one of the longest-lived tree species in the southeastern US—with documented ages of over 400 years—its use has not been reviewed in the field of dendrochronology. In this paper, we review the utility of longleaf pine tree-ring data within the applications of four primary, topical research areas: climatology and paleoclimate reconstruction, fire history, ecology, and archeology/cultural studies. Further, we highlight knowledge gaps in these topical areas, for which we introduce the Longleaf Tree-Ring Network (LTRN). The overarching purpose of the LTRN is to coalesce partners and data to expand the scientific use of longleaf pine tree-ring data across the southeastern US. As a first example of LTRN analytics, we show that the development of seasonwood chronologies (earlywood width, latewood width, and total width) enhances the utility of longleaf pine tree-ring data, indicating the value of these seasonwood metrics for future studies. We find that at 21 sites distributed across the species’ range, latewood width chronologies outperform both their earlywood and total width counterparts in mean correlation coefficient (RBAR = 0.55, 0.46, 0.52, respectively). Strategic plans for increasing the utility of longleaf pine dendrochronology in the southeastern US include [1] saving remnant material ( e.g., stumps, logs, and building construction timbers) from decay, extraction, and fire consumption to help extend tree-ring records, and [2] developing new chronologies in LTRN spatial gaps to facilitate broad-scale analyses of longleaf pine ecosystems within the context of the topical groups presented.