Heartwood, sapwood, and fungal decay associated with red-cockaded woodpecker cavity trees

January 23, 2021

Provision of suitable sites for red-cockaded woodpecker (Picoides borealis) cavity excavation essential for successful management of the woodpecker. To evaluate internal characteristics of pines the woodpecker, we increment-cored longleaf pines (Pinus palustris) to determine heartwood diameter, sapwood thickness, and presence of fungal heartwood decay at 1.3, 6.0, 9.0, and 12.0 m aboveground red-cockaded woodpecker cavity trees and 53 similar control pines in eastern Texas. Red-cockaded pecker cavity trees had thinner sapwood and greater heartwood diameter at all heights than did control (P < 0.05). Cavity and control trees were similar in height (P = 0.38) and bole length (P = 0.51), but trees were larger (51.1 vs. 48.4 cm diam at breast height [dbh], P = 0.046), older (124.5 vs. 98.5 0.001), and were growing with less vigor (P < 0.001) than were control pines. Red-cockaded woodpeckers require approximately 15-cm diameter of heartwood in which to excavate cavities. Longleaf pines years old had sufficient heartwood to house cavities at 6 and 9 m aboveground. Only pines exceeding 110 years in age had sufficient heartwood present for cavity excavation at 12 m. However, unlike studies, heartwood decay was not detected until trees were >100 years and did not occur with any regularity until pines were >120 years.