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Land Use Forecasts

Urban growth scenario—The urban growth scenario evaluates potential changes in land use driven by anticipated changes in population, personal income, and housing values in the South. Relative returns from agricultural and forestry uses are held constant at their 1992 values. The focus, therefore, is on changes in the factors that influence the distribution of land between urban and rural uses. Forecasts were made for 2020 and 2040 and examined in detail for 2020.

The urban growth scenario indicates a growth in urban area from about 20 million acres in 1992 to 55 million acres in 2020 and to 81 million acres in 2040 (fig. 6.10). Without price adjustments in rural land markets (addressed later), land would shift out of agricultural, forest, and other uses. Forest area declines by about 12 million acres, agriculture by about 13 million acres, and other by about 7 million acres.

In the forecast for 2020, substantial population and income growth are projected for about one-third of the region’s counties. Urbanization is concentrated in three large areas (fig. 6.11): (1) the Southern Appalachian Piedmont stretching from Raleigh/Durham, NC, through Atlanta, GA; (2) the Atlantic Coast from the Carolinas through Florida; and (3) a portion of the gulf coast centered on Mobile Bay. Other centers of expanding urbanization are around Nashville and Knoxville, TN, and in northern and eastern Virginia.

Urbanization dominates rural land use, reducing the areas of both agricultural and forestry uses. Especially large losses of agricultural land are anticipated in Florida, central Tennessee, and central North Carolina (fig. 6.11B).

Losses of forest land are concentrated in areas of expected urbanization (fig. 6.11C). The Southern Appalachian Piedmont of the Carolinas and Georgia, central Tennessee, and Florida all are expected to experience substantial losses of forest land in response to population and income change.

Mapping changes in land use by ecological section shows that forest loss will generally be concentrated in the eastern half of the South. The ecological section with the greatest loss will be the Southern Appalachian Piedmont. Figure 6.12 again shows forest losses would be high along the entire Atlantic Coast and the gulf coast of Florida. The largest contiguous block of forest loss will include the Southern Appalachian Piedmont, the Blue Ridge Mountains, the Ridge and Valley, and the Southern Cumberland Plateau.

Base scenario—The base scenario shows how the urban growth scenario would be altered if timber rents continued to increase relative to agricultural rents consistent with the timber base modeling in chapter 13. A 35-percent increase in real forest rent relative to real agricultural rent is forecast for 2020; a 75-percent increase is forecast for 2040.

The expected increase in timber prices has two effects shown by comparing the urban growth and base scenarios. One is to dampen slightly the demand for land in urban uses. As a result, urban land is forecast to be at about 52 million acres rather than 55 million acres in 2020 and at 72 million acres rather than 81 million acres in 2040. The other effect is that some agricultural land would be planted to forest cover. Roughly 8 million acres would be planted by 2020 and 23 million acres by 2040 (fig. 6.10). The estimate of planting area is the difference between the areas of agricultural land use for the urban growth and base scenarios. The net effects are: (1) urban area expands, (2) forest change is nil, and (3) agricultural and other land declines. Consistent with history, gross changes among land uses would continue to be substantial.

The increase in timber prices leads to shifts from agriculture to forest in the South in 2020. Certain areas of the South may be especially sensitive to these changes (fig. 6.13). In the eastern half of the region, two areas show an increase in forest area. One is a small area in the upper Coastal Plain centered on the border between North Carolina and Virginia. The other is the entire upper Coastal Plain of Georgia and parts of the Coastal Plain of South Carolina. These findings are consistent with a recent study by Ahn and others (2001), who also found the potential for gains in forest land in spite of urban pressures in the western half of the South.

However, the largest block of potential gain in forest land would lie in the western one-third of the South. This area includes the southwestern quadrant of Alabama and nearly the entire States of Mississippi, Louisiana, and Arkansas. In this area, rural land use appears to be very sensitive to changes in relative returns to agricultural and forestry (fig. 6.14) (table 6.3).

As significant as the areas showing gains in forest area is a large contiguous portion of the region showing little response to increasing forest rent. This area reaches from the northern parts of South Carolina, Georgia, and Alabama to the northern boundary of the Assessment area.

Sensitivity analysis—A sensitivity analysis of the effect of timber price changes shows that the margin between agricultural and forest land uses could be relatively flexible. The urban growth scenario forecast a loss of about 12 million acres of forest land; the scenario with a 10-percent increase in real timber prices forecast a loss of about 8 million acres. If the real timber price were to increase by 20 percent from 1992 to 2020, forest land loss is forecast to be 3.5 million acres. A 30-percent real price increase results in essentially no net change in forest land in the South.

This sensitivity analysis has focused on upward movement in the timber-to-agriculture rent ratio. If this rent ratio were to fall—if agriculture rents rise relative to timber—we would expect the reverse. Forest land would move toward agricultural uses at the margin.