Trends in Use of Silvicultural Practices

(Table 14.1) and (Table 14.2) show FIA results regarding current annual use and trends in use of forest management practices, including clearcutting, partial cutting, thinning, TSI, site preparation, burning, planting, and natural regeneration.

Clearcutting occurs on about 2 million acres annually. Upland hardwood accounts for 38 percent of harvested land and is followed by planted pine with 22 percent. The area of clearcut planted pine is probably higher as planted pine stands with a larger hardwood component are classified as oak-pine. If this indeed is the case, then planted pine clearcut area would be similar to upland hardwood. Clearcutting is most common on NIPF land, which accounts for 57 percent of harvested area. This result is an expected result because NIPF owners hold the majority of timberland in the region. Acreage of clearcutting has grown by nearly 10 percent over the period covered by the FIA surveys or a 1.4-percent annual increase from 1986 to 1993. While clearcutting increased on PB, NIPF, and MC land, it actually decreased on FI land. The total annual clearcut area amounts to only about 1 percent of timberland area in the region. This result indicates that management is relatively extensive in the Souths timberland. Partial cutting is much more widespread, occurring on about 3.3 million acres annually. It has increased by 12 percent over the period between the two FIA surveys (Table 4.1: Intensively Managed planted pioen growth and yield data (wood volume) for medium sites and 25-year rotation) (Table:Table 4.2- Extent of intensive forest management practices in the South ).

Approximately 640,000 acres are thinned annually. This practice is most often used in pine plantations and on FI land, which account for 48 percent of the total thinned area. Considering the size of FI timberland area, this result indicates relatively high thinning intensity. The total thinned area increased by nearly 3 percent between the FIA surveys. The largest increases in thinning area of up to 74 percent occurred on FI and MC land. Thinning intensity decreased on PB land.

TSI operations are carried out on about 940,000 acres annually. This area has increased by about 74 percent between the FIA surveys. The largest increases also occurred on FI and MC land. Natural pine forests account for 39 percent of TSI land, and planted pine forests account for 30 percent.

Nearly 1.2 million acres are site-prepared annually. About 60 percent of site preparation is for pine planting. Much of the rest is for natural regeneration of pine. FI land accounts for 54 percent of site-prepared area. While site-prepared area has been relatively stable, there were some changes among ownership groups. MC owners increased site-prepared area by 56 percent, while PB and FI owners decreased their acreages of site preparation.

Burning is the only management practice that became less common. Currently, it occurs on nearly 2.3 million acres annually, primarily on FI and NIPF land. The total number of burned acres has decreased by nearly 4 percent. Burning is most frequent in natural and planted pine stands.

Annually, 1.6 million acres are planted, both for reforestation and afforestation. Planting rates have increased by 25 percent between the FIA surveys or about 3.6 percent per year. Pines dominate 75 percent of planted land. In addition, planted pines occur in oak-pine stands in which hardwoods make up over half of the stocking. Between the surveys, NIPF owners and MC owners have increased planting rates by 85 and 68 percent, respectively. Natural regeneration is practiced on nearly 1.7 million acres annually. Between FIA surveys, naturally regenerated area increased by 18 percent.

Nearly 1.6 million acres of planted pine were fertilized in 1999 (North Carolina State Forest Nutrition Cooperative 2000). The increase from 1990 is nearly 800 percent. Nearly 10 million acres were fertilized in the South since 1969. This area is estimated to exceed the sum of forest fertilization in the rest of the World taken together. While the exact distribution of fertilized land among forest owner groups is not available, the Forest Nutrition Cooperative data indicate that fertilization is primarily the domain of FI and TIMOS. Fertilization will likely become even more popular in the future as new, more intensive silvicultural systems are introduced. Assuming that we have about 34 million acres of planted pine that will be fertilized at least twice during the rotation, fertilized area could at least double from todays levels.

Data on herbicide application were not available, but some inferences can be made about the area on which it is practiced. Results of forest owner surveys, discussed in the following sections, indicate that herbicide is applied together with fertilizer in higher management regimes. These results, coupled with planted pine area estimates and the assumption of a 25-year rotation length, indicate that herbicide might be applied on about 1.5 million acres annually.

Overall, rapid increases in harvest rates, planting and natural regeneration, TSI, and chemical applications indicate increasingly intensive management of southern forests. Intensive forest management is practiced primarily in pine plantations, which account for most planting, site preparation, fertilizer application, and thinning.

Naturally regenerated forest types are managed less intensively than pine plantations. Thinning, TSI, and burning are most common in natural pine, followed by oak-pine. Between the FIA surveys, oak-pine stands experienced substantial increases in clearcutting (40 percent), partial cutting (48 percent), TSI (102 percent), site preparation (118 percent), and burning (29 percent). These increases may result to some extent from classifying planted pine stands with a larger hardwood component as oak-pine. Hardwood forests are managed primarily in natural stands. They account for most forest land that is harvested and naturally regenerated, which is conditioned on their extensive cover in the region. FIA results indicate that areas of clearcutting, partial cutting, TSI, planting, and natural regeneration increased moderately, while thinning, site preparation, and burning became less popular between the surveys.

FI and MC holdings are managed most intensively, and intensity of management has increased markedly. Management intensity of NIPF land is also increasing, but to a lesser extent. Management intensity on PB land, the smallest ownership category in the South, appears to be changing as well. Clearcutting, TSI, planting, and burning have increased. Partial cutting, thinning, site preparation, and natural regeneration have decreased.

Changes in stand structure (even-aged, two-aged, and uneven-aged) management are difficult to determine due to the lack of data. About 34 million acres of planted stands are in planted pine or oak-pine forest types. These stands are managed in even-aged systems. With few exceptions, the remaining stands were regenerated naturally. Depending on natural growth conditions, types of cutting, and other disturbances, they may represent any of three age structures. Implementation of uneven-aged management systems is quite complex, and many uneven-aged forests probably were not established intentionally. Some FI firms practice two-aged and uneven-aged silviculture in hardwood forests.