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Broad Forest Types

Primary Question (chapter 16): What are the history, status, and projected future of southern forests?

Related Question (chapter 13): What are the history, status, and projected future demands for and supplies of wood products in the South?

While the total area of timberland in the South has remained relatively stable, forest types have changed (fig. 34). Five broad categories of forest types are recognized by FIA: upland hardwoods (including oak-hickory and beech-birch-maple), lowland hardwoods (including oak-gum-cypress), natural pines (including longleaf, slash, shortleaf, and loblolly not established by planting), planted pines (all species), and mixed oak-pine. Pine forest types have experienced the most change. The area of natural pine has declined from about 72 million acres in 1953 to about 33 million acres in 1999. Planted pine has increased from about 2 million acres in 1953 to more than 30 million acres in 1999. Upland hardwoods have increased somewhat between 1953 and 1999. Lowland-hardwood areas declined somewhat between 1962 and 1970 but have been essentially stable since the 1970s.

Changes in broad forest types are brought about by forest succession and by forest management. Data for the 1980s and 1990s show that 28 percent (3.3 million acres) of new pine plantations came from forest that was previously natural pine. Forty-seven percent (5.7 million acres) was derived from hardwood and oak-pine forest types, and another 25 percent (3 million acres) was derived from agricultural land. Over this same period, 9.2 million acres of natural pine were reclassified as hardwood and natural oak-pine types, reflecting a natural succession from pine species to more shade-tolerant species such as oaks and hickories, or harvesting of the pine component from these forests.

Upland hardwood acreage has been gradually increasing since the 1950s. Between the 1980s and the 1990s, 3.4 million acres of natural pine types shifted to upland hardwood. At the same time, 5.9 million acres of upland hardwood types were reclassified as natural pine and oak-pine types. Hardwood forest types experienced the greatest amount of conversion (2.2 million acres) to nonforest uses over this period.

Lowland hardwood forest types declined in area between the 1950s and the 1990s, with most losses occurring between 1960 and 1970. Since then, losses have been more gradual. Much of the loss in the 1980s and 1990s resulted from reclassification to other natural forest types, but 634,000 acres were planted to pine and 864,000 acres were converted to nonforest uses during these years.

The area in pine plantations is forecast to rise by 67 percent from a little more than 30 million acres in 1999 to 54 million acres in 2040 (fig. 35). Twenty-three million acres of agricultural land are forecast to be planted over this period. These forecasts indicate that forests of all types will be lost to urban uses, that most gains in planted pine will come from converting agricultural fields (fig. 36), and that the remainder of gains will come from converting other forest types. This forecast departs from historical trends of about 25 percent of plantations from agricultural fields in the 1990s, but reflects a strong demand for plantations in areas that are already managed intensively. In these areas, where conditions are good for growing pine, the availability of other forest types will become limited, and agricultural land will supply an increasing share of area for plantations.

Figure 36—Forecast of the area timberland by forest types (million acres), 1995-2040.

The areas of all other forest types are forecast to decline at gradual rates (chapter 13), with a net reduction of 25 million acres (17 percent) between 1995 and 2040. These trends vary by State. Substantial declines in nonplanted forest area are forecast for Florida (58 percent), South Carolina (35 percent), and North Carolina (30 percent). Alabama, Georgia, Texas, and Virginia are forecast to lose between 18 and 23 percent of nonplanted forest types by 2040 (chapter 13).