Emerging Issues in the South

Hemlock Woolly Adelgid
The health and competitiveness of Southern forests is being impacted by changing local and global markets, invasive species, shifting consumer demands, and declining economic viability of the private forest landowner. There are ways to both promote the conservation ethic, manage forests for a multitude of resources (traditional and nontraditional), and provide economic gains to the landowner.

Program Overview

Hemlock woolly adelgid (HWA) is a non-native invasive pest that impacts eastern hemlock and Carolina hemlock. HWA has spread to the Southern Appalachian region of northern Georgia, western North Carolina, eastern Tennessee, and southern Virginia. Without control, hemlocks typically die within five to seven years after infestation.

Hemlock trees serve important ecological roles in the southern Appalachians. They are a keystone species in near-stream areas, providing critical habitat for birds and other animals, and shading streams to maintain cool water temperatures required by trout and other aquatic organisms. Hemlocks are also prized for their visual beauty in both forest and urban settings, and are a contributor to residential property values.

Program Performance

An integrated program among Forest Service research, State and Private Forestry, and university cooperators provides science-based management strategies for addressing HWA. Program goals support an agency, Department, OMB, and Congressional priority to control major forest pest and pathogens to ensure healthy forests.

Program Highlights

A comprehensive research and development program has focused on the following key elements of HWA concerns – 1) identifying and providing environmentally safe control options for hemlock woolly adelgid, 2) improving survey methods to monitor pest populations and impacts on hemlock stands, 3) providing guidelines for restoration of damaged forest stands, and 4) identifying and developing host-plant resistance to HWA.

Research Accomplishments

Station research on HWA has resulted in “Guidelines to Minimize the Impact of the Hemlock Woolly Adelgid” to provide information for forest managers to guide response to HWA. Scientists have also developed procedures to protect high value hemlock trees using insecticide treatments that are safe and effective up to three years. Research is also leading to an increased understanding of hemlock mortality on forest health – critical for producing tools and developing strategies to mitigate impacts and restore the health and sustainability of damaged stands.

Program Potential

The combined efforts of the Southern and Northern Research Stations, working with State and Private Forestry and university cooperators throughout the East, could provide improved tools and cost-effective strategies to mitigate long-term impacts of HWA. Research efforts will be centered at the Coweeta Hydrologic Laboratory in Western North Carolina.

Research Priorities

Improving Control Strategies to Reduce or Eliminate the Spread of HWA
Biological and chemical controls offer the best solution for reducing or eliminating the spread of HWA in the southern Appalachians. Research conducted over the past three years has provided much information on control strategies and success; however, HWA has not been eliminated and better tools and information will be required by land managers to improve control efforts.


Improving Understanding of Impacts of HWA Mortality on Forest Health
While scientists and land managers are hopeful that biological and chemical controls will be successful, it is likely that large areas of the southern Appalachians will experience significant HWA-related mortality. Land managers need to know the impacts of mortality on forest health in order to develop restoration strategies and prioritize control efforts.













Improve Understanding of Rates and Patterns of HWA Spread
Tools and information that predict the rate and direction of HWA spread are needed by land managers to help plan and prioritize costeffective control and restoration efforts.













Provide Tools to Improve the Health and Sustainability of Impacted Stands
While scientists and land managers are hopeful that biological and chemical controls will be successful, it is likely that large areas of the southern Appalachians will experience significant HWA mortality. Land managers will be faced with developing management strategies to restore forest health in stands with significant levels of mortality.





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Maintaining healthy Southern forests requires an understanding of changing market conditions, rapidly evolving forest threats, and the socio-economic aspects associated with landowner decision making. Incentives and new markets for ecosystem services and biomass are encouraged to support keeping forest lands in working forests, thus preventing fragmentation and loss of habitat. The capacity of States to deliver training, science, and assistance to landowners is essential for success.






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