Implications

Changes in southern forest quantity and/or quality due to these drivers of change may have implications for southern forest ecosystem services. For example:

• In those areas where suburban encroachment is prevalent, where disease/pathogen outbreaks occur, or where wildfires emerge, the supply of timber and/or pulpwood may decline. Suburban encroachment (specifically due to smaller management parcels and increased land values) corresponds with lower rates of forest management for timber and other wood products. According to the U.S. Forest Service, at approximately 45 people per square mile, there is a 50 percent chance a forest owner will practice forestry. At 150 people per square mile, the likelihood approaches zero percent.¹
• Production of biomass energy from southern forests will likely increase if policies stimulating biomass-to-energy demand emerge.
• Where forests are converted to alternative land uses, the carbon storage potential of the landscape will decrease since forests have a higher carbon storage potential than any other land use in the South.
• Where agricultural land reverts to forest, the carbon storage potential of the landscape will increase.
• In areas where forests are converted to development, forest-based recreation and tourism opportunities will decline. As a result, hiking, camping, wildlife viewing, and other recreational activities may become concentrated on fewer forest acres.²

Ecosystem services

In general, less forest area—or less healthy forests—means fewer forest-based ecosystem services. It is important to note, however, several caveats including:

• The precise implications for particular services will vary by location. In some geographic areas of the South, the quantity or quality of an ecosystem service may increase while in other areas it may decrease.
• The precise implications for particular services will depend in part on the capacity of southern forests to adapt to pressures such as disease, drought, and climate change. This capacity is determined by multiple factors, including levels of biodiversity, forest intactness, and number of stressors.
• Likewise, the precise implications for particular services will depend in part on forest management practices people take in response to the drivers of change. For example, if the number of private landowners that allow public recreation or hunting opportunities in their forests were to increase sufficiently in response to declining forest extent around suburban areas, then the supply of these cultural services may remain stable or actually increase over time.
• Practices, natural processes, and other factors may diminish some of these projected trends in ecosystem services. For instance, to the degree that foresters, farmers, and developers implement forest buffers or streamside management zones, the ability of the landscape to control erosion may in part be retained. Likewise, as suburbs age, landscape trees develop into a canopy that can provide ecosystem services such as local climate and air quality regulation, as well as habitat for wildlife.
• Quantitative information about a forest’s supply of—or ability to supply—many regulating services and some cultural services is often sparse or nonexistent. Therefore, measuring, monitoring, and forecasting changes in these ecosystem services can be difficult. This feature, however, is not unique to southern forests; it is a challenge for ecosystem assessments worldwide.³
• Further quantitative research on the interaction among southern forest-based ecosystem services and ecosystem service production functions is needed. For example, modeling and other assessments would help answer increasingly pertinent questions, such as: What are the biophysical and ecosystem service trade-offs between managing southern forests for timber, pulpwood, biomass energy, and carbon? To what degree may there be supply constraints between the ecosystem services of timber, pulpwood, and biomass energy in southern forests over coming decades? What approaches are available for a landowner to optimize the supply of a suite of ecosystem services?

Biodiversity

Changes in southern forest quantity and quality will have implications for the region’s biodiversity, as well. For example:

• Suburban encroachment threatens to increasingly fragment the southern forest landscape into smaller, isolated patches. For species that prefer large tracts of undisturbed forest, fragmentation can diminish available habitat and create barriers to movement, thereby decreasing connectedness among individuals and populations, increasing roadside mortality, and decreasing access to food. Affected species in the South include bobcat, black bear, and neotropical migratory birds such as certain species of warblers and tanagers.⁴⁵ On the other hand, forest fragmentation can increase available habitat for those species such as white tail deer, which prefer “edges” between forest and non-forest ecosystems.
• Habitat loss and fragmentation have been a leading factor in plant and animal species becoming rare around the world. The same is true in the southern United States. The South already has more than 130 “species of conservation concern” (Table 4.2). Further declines in forest quantity and quality will make it difficult to remove species from this list and could add more.
• The survival of some tree species in the wild will be threatened by expected pest and pathogen outbreaks. For example, the hemlock woolly adelgid is projected to decimate eastern hemlock. Butternut canker is expected to eliminate butternut trees from the South.⁶
• Climate change is projected to shrink the range of red spruce and other species adapted to higher-elevation, cooler climates.⁷