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1 Key Findings

· Insects and diseases have had considerable impact on southern forests during the past century, and serious damage from native pests and exotic invasive pests is expected to continue.




· Generally, the more diverse and vigorous a stand, the less likely it is to suffer significant insect or disease damage. As diversity decreases or vigor declines susceptibility to catastrophic pest damage increases.




· Longleaf pine is the least susceptible of the southern pines to most insect and disease pests currently affecting Southern forests, and its restoration on former longleaf pine sites currently forested with loblolly, slash, and shortleaf pine should lessen the impact of known insect and disease pests in those areas.




· Because of land use history and the decimation of American chestnut by the chestnut blight, oaks probably represent a larger component of the southern forests today than at any time in the past.




· Oak decline will continue to be a forest health issue in the region especially on national forest land, which has a higher frequency of attributes that are important in oak decline etiology (old trees, low soil fertility, and shallow soils). Among national forests, the George Washington and Jefferson have the highest incidence of this disease.




· In central Texas, oak wilt has emerged as a major disease, causing significant damage to an environmentally restricted and vulnerable resource that is primarily valued for aesthetics.




· The southern pine beetle will play an increasingly important role in the future of the South's pine forests. Catastrophic population buildups will continue to occur, especially in overstocked, old, less-vigorous forests.




· For virtually all pests, stand age and density, tree size, and species composition affect pest behavior. Forest pest impact is greater in less intensively managed forests, and on small private tracts and public landholdings than on private industrial forests.




· Integrated pest management, which employs silvicultural methods and various mechanical, manual, biological, and chemical tools, is the most successful strategy currently available for pest management.




· Introduced insect and disease pests have the potential to permanently alter ecosystems in the South.




· American chestnut has been eliminated from its niche by chestnut blight, caused by an introduced fungus.




· Dogwoods are being eliminated from their native habitats above 3,000 foot elevation by dogwood anthracnose, caused by another introduced fungus.




· Damage by the beech bark disease (caused by a complex of introduced insects and fungi) has only just begun in the South; barring an unpredicted natural barrier or research success, it is expected to spread throughout the southern range of American beech and permanently reduce it from a codominant tree species to a deformed mid- to understory species.




· All eastern and Carolina hemlocks, except for treated trees and geographically isolated populations, could be killed by an introduced insect, the hemlock wooly adelgid.




· Butternut and Fraser fir are now candidate species for listing under the Endangered Species Act due to the activity of the introduced balsam wooly adelgid.




· The gypsy moth and the fungus causing butternut canker, both introduced species, are expected to significantly increase in activity in the South during the next 30 years, permanently altering the species composition of affected southern forests.




· Data are not available on pest management (including silvicultural manipulation and pesticide use) on private land in the South.




· Brown-spot disease has been estimated to reduce total annual growth of southern pines by 16 million cubic feet (0.453 million cubic meters). Existing management strategies could significantly reduce this loss.




· Extensive planting of susceptible slash and loblolly pines since the 1930s has resulted in a continuing epidemic of fusiform rust. Damage appears to have reached equilibrium. At present, fusiform rust infects at least 10 percent of the slash or loblolly pines on over 13.4 million acres (28 percent of the host type) southwide. Use of available, genetically improved, disease resistant seedlings, and intensively managing infected stands have the potential of reducing this damage.




· Concern about importation of oak wilt to Europe has caused the European Economic Community to impose a quarantine on the importation of oak logs from United States counties where oak wilt has been documented.




· Reproduction weevils can cause 30 to 90 percent mortality in planted seedlings in the south




· Average annual losses caused by the southern pine beetle in the Southern U.S. exceed 100 million board feet of sawtimber plus 20 million cubic feet of smaller sized growing stock. From 1991-1996, total value of trees killed by the beetle in the South was estimated at $493 million. Although yet to be tried on a broad scale, prevention strategies currently available to forest managers are believed to have the potential to reduce the damage caused by this insect.




· Hardwood borers are estimated to cause more than $29 million in loss (timber value) per year. Periodic outbreaks of specific borers, such as the current epizootic of the red oak borer in northern Arkansas, cause significant damage to forest ecosystems and local economies.