Guidelines for Regenerating Southern Pine Beetle Spots

 

Composite photo showing southern pine beetle hot spot, damage to individual tree, and southern pine beetle. Photos by U.S. Forest Service, courtesy of Bugwood.org.
Composite photo showing southern pine beetle hot spot, damage to individual tree, and southern pine beetle. Photos by U.S. Forest Service, courtesy of Bugwood.org.

Guidelines for Regenerating Southern Pine Beetle Spots, a general technical report (GTR) by the Southern Research Station (SRS),  provides detailed guidance for regenerating pines in areas within forest stands where trees have been killed by southern pine beetle.

Authored by scientists from two units located in Pineville, Louisiana—the SRS Restoring and Managing Longleaf Pine Ecosystems unit and the SRS Insects, Diseases, and Invasive Plants unit—the GTR includes a key to help managers plan for regenerating spots within the context of the larger forest stand.

It’s hard to overestimate the economic and ecological importance of pine forests in the South, a region which is widely known as the Nation’s “wood basket.” The main pine species in the region are loblolly, slash, longleaf, and shortleaf. Loblolly pine, the most widely distributed and most commercially important tree species in the South, is vulnerable to infestations of southern pine beetle, a native insect.

The southern pine beetle is the most destructive forest pest in the southern United States. The most recent outbreak of the native insect (1999-2003) caused over $1 billion in damages across five states. Unlike most native insects, southern pine beetle kills its host trees in clumps—called spots—where almost all the trees are killed.

When trees start dying from southern pine beetle, overstory gaps form quickly, affecting the structure and functions of the larger stand. Managers may need to intervene to stop these spots from spreading and to regenerate affected stands. With large gaps or a string of small gaps, they can use their usual techniques to regenerate the area, reducing susceptibility to future southern pine beetle infestation by planting at lower densities, planting more resistant species such as longleaf pine, and other activities.

Southern pine beetle damage to a stand. Photo by Erich Vallery, courtesy of Bugwood.

Small gaps, or spots, are more common than large ones and offer particular challenges to forest managers. Most regeneration methods are designed for the stand level, while spots represent only a small portion of the stand. Remaining trees at the edges of small spots compete with seedlings for light and nutrients, making pine regeneration difficult. Hardwoods will also start growing in the gaps and will outcompete young pine seedlings unless controlled.

How a manager responds to southern pine beetle spots depends on the goals they have for the stand in terms of timber production, management of game and nongame animal species, preservation of water resources, recreational use, and other factors.

The authors of the publication developed guidelines and a key to provide managers a suggested course of action to regenerate southern pine beetle spots in relation to their goals, stand conditions, and the nature of the insect infestation. Managers can use the key to identify the information needed to decide on a particular set of actions, or prescriptions. The key in turn leads to specific prescriptions to help forest managers meet their goals with both present and future stands.

Access the full text of the GTR.

For more information, email Mary Anne Sword Sayer at msword@fs.fed.us.

Access the latest publications by SRS scientists.

 

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