Southern Pine Beetle
The southern pine beetle (SPB; Dendroctonus frontalis) is a rice-sized native bark beetle ranging from Texas to Pennsylvania and from Arizona to Honduras in Central America. Over the last 10-15 years it has been increasing its range northward due in part to higher winter temperatures. It was detected in New Jersey in 2001 and on the south shore of Long Island in September 2014. Considered one of the most destructive insect pests in the country, it has the potential to kill thousands of acres of pines during an outbreak. In 2010 alone, SPB damaged over 14,000 acres of pitch pine (Pinus rigida) in the New Jersey Pinelands.
Pitch pine, the predominant tree species of the Long Island Pine Barrens ecosystem, is a preferred host species for SPB. Attacks are initiated by female beetles when they find a suitable host tree. They release pheromones attracting hundreds to thousands of beetles to a tree, overwhelming it. SPB kills trees in two ways: a) adult female beetles and larvae construct a network of S-shaped tunnels through the cambial layer which prevents the transport of carbohydrates to the roots, and b) SPB introduces blue-stain fungus (Ceratocystis polonica) which impedes the circulation of water throughout the tree, further stressing it. In the New Jersey Pinelands SPB can have up to seven generations in a year and tree mortality can occur in just a few short months.
Why is SPB a threat to our forests?
SPB is now widespread throughout the forests on Long Island and has the potential to seriously impact the Long Island Pine Barrens. Long Island’s forests have never been actively managed. Unlike many other areas of the country and even New York State where forests are managed for timber, our forests do not experience regular thinning, and fire which is a nature’s way of regulating itself, has been removed from the ecosystem.
This lack of management has created forests that are too dense and full of over-mature trees. This results in unhealthy, stressed forests because all the trees are competing for resources (e.g., water, sunlight, and nutrients) and thus, none are getting what they need to thrive. Stressed trees produce less oleoresin—their primary defense against insect attacks, and so they have lowered resistance to pests like SPB. In addition, without fire to consume leaf litter and other surface fuels to expose mineral soil, once the existing pitch pine trees die new pitch pines cannot germinate which could result in the complete loss of our pine barrens ecosystem.
Management of SPB
A landscape level management plan was developed by the NY State Department of Environmental Conservation (NYSDEC) in collaboration with the US Forest Service (USFS), Cornell University, Dartmouth University, and many others which will help us prioritize management to mitigate impacts of SPB to our forests.
Aerial and ground surveys conducted at BNL have shown that SPB can be found throughout the Lab, both in the central campus area around buildings as well as in the approximately 3,600 acres of forest on site. Populations are being monitored and management options are being explored. BNL has been consulting with the NYSDEC, the USFS, and others to determine possible long term solutions to dealing with this pest including suppression and preventative thinning. Suppression involves the cutting of infested trees plus an additional buffer of uninfested trees which disrupts the pheromone trail and slows the spread of infestations. This is only feasible for very small infestations, however.
Preventative thinning is the selective removal of trees from the forest. When used in conjunction with prescribed fire the benefits are twofold: a) in the short term, more open stands disrupt pheromone communication, and b) in the long term, a reduction in tree density results in healthier trees that are more resilient to SBP attacks.
