22 Jan 2026

Assessing Longer-Term Effectiveness of Forest Management Guidelines on Breeding Habitat for Cerulean Warblers

Abstract: Widespread clear-cutting in the late 19th and early 20th centuries and subsequent regrowth has resulted in homogenous, closed-canopy forest structure across much of eastern deciduous forests in temperate North America. Forest management prescriptions designed to diversify stand structure have been increasingly applied with the goal of improving breeding habitat for declining species that require heterogenous forest structure, including Cerulean Warblers (“ceruleans”; Setophaga cerulea). Although a few studies have documented positive short-term (1–4 years post-treatment) responses of ceruleans to forest management prescriptions in the Appalachian Mountains region, longer-term responses have yet to be assessed. In 2019–2020, we followed the same spot-mapping methods as used previously (2005–2006 pre-harvest and 2007–2010 post-harvest) and compared territory density with previous estimates at each of 4 treatment levels (reduced basal area and overstory canopy by 0–75 %) across four forest stands on study sites in Tennessee, Kentucky and Ohio (n = 12 stands total) that had exhibited short-term positive density responses. Ceruleans did not exhibit consistently positive longer-term responses compared with pre-treatment densities when all stands were analyzed together. Compared with pre- treatment surveys, after 13–14 years post-harvest we documented density decreases of 1.0–3.1 territories per 10 ha at 5/9 stands, and positive responses of 1.8–2.2 territories per 10 ha at 3/9 treated stands. Over this period, midstory cover changed significantly (increased) during the 10 years since these stands were last surveyed. Thus, sustaining the short-term (1–4 year) positive response of cerulean warbler territory density to timber harvest may require periodic follow-up treatments that reduce the development of a dense midstory; we recommend that this hypothesis, along with the methods to achieve these conditions, should be tested.