Assessing the Threat of Southern Pine Beetle to Pitch Pine in Acadia National Park

Caroline R. Kanaskie^1,*, Mark J. Ducey², and Jeff R. Garnas²

¹University of Maine at Fort Kent, Division of Natural Sciences, 23 University Drive, Fort Kent, ME 04743. ²University of New Hampshire, Department of Natural Resources and the Environment, 56 College Road, Durham, NH 03824. *Corresponding author.

Northeastern Naturalist, Volume 33, Issue 1 (2026): 23–43

First published early online: 13 February 2026

Abstract
Many of the mountain summits of Acadia National Park (ACAD) are dominated by Pinus rigida (Pitch Pine). The ACAD Pitch Pine population is particularly valuable due to its position at the northernmost edge of the species’ range, its association with unique animal and plant communities, and its contribution to the aesthetics of the park. Pitch Pine is host to Dendroctonus frontalis (Southern Pine Beetle [SPB]). As the name suggests, SPB is native to the southeastern US, and can kill large numbers of healthy pines via mass-attack. With warming winters, SPB can establish and persist further north than ever before, presenting a novel and emerging threat to hard pines in New England, including Pitch Pine. While SPB has not yet been found in ACAD, SPB infestations have occurred at Fire Island National Seashore (FIIS), and individual beetles have been trapped at Cape Cod National Seashore (CACO) and as far north as Waterboro, ME. We present data recorded by temperature sensors that we set out in each park during 2023–2024. Minimum temperatures in winter 2023–2024 were not cold enough to suppress SPB population growth in ACAD, CACO, or FIIS. We assess hazards posed by advancing SPB populations to Pitch Pine in ACAD by quantifying known drivers of SPB infestation risk, including Pitch Pine stem density and basal area. We found that 66% of plots sampled in ACAD had high Pitch Pine basal area as defined by previous work on SPB risk. These areas of high-density Pitch Pine were not correlated with environmental variables like elevation or fire history. We place these findings in the context of the resist–accept–direct management framework.

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