Old SPB stuck in pine resin (Photo: Robyn Graygor)
On Saturday, January 17, BiodiversityWorks Director, Luanne Johnson, Wildlife Technician, Silas Beers, and I ventured off to the mainland to attend a Massachusetts Division of Fisheries and Wildlife southern pine beetle (SPB) event in the Mashpee Pine Barrens. A large group gathered in the Mashpee Wampanoag Council parking lot near a neighboring SPB infestation site. MassWildlife staff guided us through several SPB spot outbreaks and explained how they’ve approached management in the area.
We weaved through tall, skeletal pitch pines (Pinus rigida) with brown needles and bare branches. Their bark crevices were decorated with small globs of dried resin, called pitch tubes, that form when impacted trees attempt to flush SPB out of the bark. If you looked close enough, you could even see some SPB that had failed to overcome this defense mechanism, now frozen in time as husks glued to the resin. These fallen soldiers are only a small portion of the attack force which can invade in the thousands.
SPB egg and feeding galleries (Photo: Robyn Graygor)
Despite being smaller than a grain of rice, 2-4 mm long, high numbers of SPB can quickly kill a healthy mature pine. This pine boring beetle, native to the Southeast U.S. and Central America, is causing significant damage to pines as it extends its range north due to climate change.
After finding a suitable host tree, female SPB send aggregation pheromones to attract more SPB and invade in mass. Once the swarm overpowers the pine resin, females will construct tunnels in the cambium layer to lay eggs. When the larvae hatch, they further damage the tree by eating away at the inner bark, disrupting nutrient flow. Accompanying blue-stain fungus infiltrates the sapwood, further harming nutrient flow by damaging water conducting tissue. This combination usually girdles and kills the tree.
SPB-introduced blue stain fungus (Photo: Ronald F. Billings, Texas A&M Forest Service, Bugwood.org)
MassWildlife has responded to active infestations in Mashpee by assessing SPB spot outbreaks, and often cutting and mulching infested trees and their surrounding buffers. This management technique is used widely to kill some of the developing brood and prevent further spread. A similar approach can be seen at Sheriffs Meadow’s Phillips Preserve.
In addition to active infestation management, MassWildlife has been working on a 30-acre habitat project to restore the Mashpee Pine Barrens and mitigate SPB damage in this imperiled ecosystem.
Restoration primarily involves applying forest thinning and prescribed burns to unnaturally dense pitch pine stands that have developed over decades of disturbance suppression (especially fire suppression). Pitch pines and many other barrens plant species are fire-adapted, which means they actually rely on periodic burns to maintain healthy structure and species composition. Urbanization has dramatically altered the natural disturbance regime, leaving fire-dependent ecosystems without fire for far too long.
Controlled burn on Martha's Vineyard conducted by The Trustees (Photo: © The Trustees)
SPB thrives in the resulting overcrowded pine stands. Stressed trees that are overcrowded and competing for resources are more vulnerable to infestation. After infesting a tree and laying eggs, reemerging adults and new adults search for trees to attack nearby. In overcrowded stands, they are able to easily find adjacent hosts and remain organized using pheromone communications to attack in mass. This ordered dispersal forms spot infestations that radiate around an initial host.
SPB-induced pitch pine (Pinus rigida) mortality at West Gate entrance to Ram Pasture on Nantucket (Photo: Nantucket Conservation Foundation)
Pitch pine (Pinus rigida) cones (Photo: Ansel Oommen, Bugwood.org).
Pitch pine woodlands exposed to periodic disturbance, like fire, have a lower tree density and an open canopy. This distance between trees can make it harder for SPB to find a suitable host and develop a spot infestation. If a tree is to be infested, it's more difficult for SPB to remain in high numbers through pheromone communications and continue expanding a spot outward.
An additional benefit to pine forests with a lower tree density is that thinned pine stands host significantly lower tick abundance and diversity. The open canopy of a thinned stand lets in more sunlight and promotes air circulation, encouraging the hot, dry conditions that deter ticks.
Disturbance also plays a major role in pitch pine regeneration. Pitch pines are shade-intolerant and require bare mineral soil for germination. Disturbance exclusion causes less fire adapted trees and understory plants to grow, which produces shade, and increases leaf litter on the forest floor. These changes favor the growth of more mesic vegetation, which threatens to overtake the pitch pine barrens ecosystem.
Part of the reason why SPB is so devastating on Martha’s Vineyard is that our cramped pitch pine barrens have accelerated the damage. These trees have been developing under adverse conditions since urbanization and fire suppression gained a foothold on the island. What's happening now is a clear illustration of how unhealthy ecosystems are less resilient in the face of climate change, and more susceptible to stress.
SPB damage on Martha's Vineyard (Photo: Matt Pelikan)
Managing these challenges at a forestry level will likely look different than managing them in a yard near a home. Conservation agencies/organizations may use prescribed burns and forest thinning, whereas it may be more realistic for the average private home owner to instead focus on individual trees and stewarding regenerating pitch pine saplings to grow less densely.
Unfortunately, once a tree has been infested, it will almost certainly succumb to the damage. If you think you’ve found SPB in Massachusetts, report sightings to the DCR Forest Health Program. Management efforts for forests and pitch pines on private properties primarily focus on preventing the spread of new infestations and handling dead trees, instead of saving an infested tree. To learn more about how property owners can respond to SPB, check out our new SPB fact sheet.
SPB in bark (Photo: USDA Forest Service - Region 8 - Southern , USDA Forest Service, Bugwood.org)
Sources:
Billings, Ronald F. “Mechanical Control of Southern Pine Beetle Infestations.” General Technical Report SRS-140, U.S. Department of Agriculture, Forest Service, Southern Research Station, 2011, pp. 399–413. USDA Forest Service, https://www.srs.fs.usda.gov/pubs/gtr/gtr_srs140/gtr_srs140_399.pdf
Brennan, Reilly N., et al. “Tick Abundance and Diversity Are Substantially Lower in Thinned vs. Unthinned Forests in the New Jersey Pinelands National Reserve, USA.” Ticks and Tick-Borne Diseases, vol. 14, no. 2, Mar. 2023, p. 102106. ScienceDirect, https://doi.org/10.1016/j.ttbdis.2022.102106.
Cameron, R. Scott. “Southern Pine Bark Beetles in the Urban Environment1.” Arboriculture & Urban Forestry (AUF), vol. 13, no. 6, June 1987, pp. 145–51. Articles. auf.isa-arbor.com, https://doi.org/10.48044/jauf.1987.031.
Clarke, Stephen R., and J. T. Nowak. “Southern Pine Beetle”. Forest Insect & Disease Leaflet 49, U.S. Department of Agriculture, Forest Service, revised Apr. 2009. Forest Health Protection, https://www.fs.usda.gov/foresthealth/docs/fidls/FIDL-49-SouthernPineBeetle.pdf.
Dickson, Meaghan. Pine Bark Beetles | Georgia Forestry Commission. 30 Apr. 2021, https://gatrees.org/pine-bark-beetles/.
Dodds, Kevin J, et al. “Expansion of Southern Pine Beetle into Northeastern Forests: Management and Impact of a Primary Bark Beetle in a New Region.” Journal of Forestry, vol. 116, no. 2, Mar. 2018, pp. 178–91. DOI.org (Crossref), https://doi.org/10.1093/jofore/fvx009.
Georgia Forestry Commission. “Pine Bark Beetles in Urban Areas”. Georgia Forestry Commission, Mar. 2025, https://gatrees.org/wp-content/uploads/2025/03/PineBarkBeetlesinUrbanAreas.pdf
Hubacz, Felicia. “MA DCR Forest Health Program.” ArcGIS StoryMaps, 3 June 2025, https://storymaps.arcgis.com/collections/21bf5260323b45389a210d9fd5e70ebe.
Jamison, Elizabeth-Ann K., et al. “Describing a Landscape Mosaic: Forest Structure and Composition across Community Types and Management Regimes in Inland Northeastern Pitch Pine Barrens.” Forest Ecology and Management, vol. 536, May 2023, p. 120859. ScienceDirect, https://doi.org/10.1016/j.foreco.2023.120859.
“Managing Pine Bark Beetles in Urban Forests.” Alabama Cooperative Extension System, https://www.aces.edu/blog/topics/forestry/managing-pine-bark-beetles-in-urban-forests/.
Massachusetts Division of Fisheries and Wildlife. “Mashpee Pine Barrens WMA Woodland Thinning FY25 Project Summary”. Massachusetts Division of Fisheries and Wildlife, 2025. Mass.gov, https://www.mass.gov/doc/masswildlife-mashpee-pine-barrens-wma-fy25-project-summary/download
Southern Pine Beetle?: Landscape?: Center for Agriculture, Food, and the Environment (CAFE) at UMass Amherst. 29 Mar. 2024, https://www.umass.edu/agriculture-food-environment/landscape/fact-sheets/southern-pine-beetle.
Stutzman, Kathleen A., et al. “Tree Regeneration Dynamics under a Range of Restoration Treatments in Northeast Pitch Pine (Pinus Rigida) Barrens.” Forest Ecology and Management, vol. 580, Mar. 2025, p. 122547. ScienceDirect, https://doi.org/10.1016/j.foreco.2025.122547.
