Using Prescribed Fire for Range Management

Prescribed burning to improve lands for grazing is one of the oldest applications of prescribed fire. Both Native Americans and early Europeans used fire to rejuvenate grazing lands (Johnson and Hale 2000). Low-intensity burns increase availability, palatability, quality, and quantity of grasses and forbs. Dead material low in nutrient value is removed while new growth high in protein, phosphorus, and calcium becomes readily available. These benefits are manifested in increased seasonal cattle weight gains (USDA Forest Service 1989).

Range Habitat

Pastures can be burned throughout the year, but are most frequently burned during the winter. Ranchers generally burn on a three to four year cycle in order to rejuvenate their pasture. One commonly used system is to divide the range into three (or four) parts and burn one third (or quarter) every year. When burning to manage a particular forage species, timing is critical since flowering dates vary among species and with latitude and elevation within a species range. Managers should observe these dates for the preferred species, and time burns accordingly. For example, wiregrass responds much better to summer burns than it does to dormant season burns. Since cattle congregate on recently burned areas, burn location and size must be carefully selected to prevent overgrazing.

One benefit of burning is improved forage quality. If an area is not burned, most forage in the South remains low in nutrient content throughout the year. Winter burns increased crude protein and phosphorus two to three times for most forage species in a Georgia pasture compared to areas that were not burned. These differences, however, were not noticeable by mid-summer (Halls et al. 1952). Other studies have produced similar results throughout the South (Lewis et al. 1982). For example, lignin quantity in forage decreased for two years following burning in Florida (Hilmon and Lewis 1962), which is beneficial for cattle because high lignin content in forage decreases digestibility.

Another benefit of prescribed burning on grazing lands is an increase in forage yields due to decreased woody species density, reduced litter layer and temporary increased nutrients following a burn (DeBano et al. 1998). After twenty years of prescribed burning in loblolly-shortleaf-bluestem range, yields on burned plots were up to 23 times higher than on unburned plots (Lewis and Harshbarger 1976). In fact, every treatment in the experiment by Lewis and Harshbarger that included burning on a regular interval had greater yields than plots that were never burned. Similar studies summarized by Lewis et al. (1982) and Wahlenberg et al. (1939) have reported that forage production increases with prescribed burning.

Cattle and other grazing animals are known to gather in recently burned areas (Wade 1989; Lewis et al. 1982; Shaw and Carter 1990). The increases in forage quality, palatability, and yield translate into greater cattle weight gains (Figure 1). In the tallgrass prairie of Oklahoma, individual animal weight gains were 11.2 kg greater per hectare on burned compared to unburned pastures (Svejcar 1989). Cattle gains were 2 to 3 times higher with burning than without in a similar study on pine-wiregrass range in Georgia (Halls et al. 1952). Many additional studies have demonstrated increased cattle weight gains with prescribed burning (Lewis et al. 1982). Wahlenberg et al. (1939) studied the impacts of prescribed burning on longleaf pine lands in Mississippi in the 1920s and 30s, and concluded that periodic burning of range lands increases cattle production.

Overall, burning and grazing are an ideal match in range management. Additional benefits may accrue by combining timber and cattle production. For example, McKee and Lewis (1983) found no adverse effects on site quality after 40 years of grazing on a longleaf-slash pine-wiregrass site on the Coastal Plain in Georgia, indicating that it is a sustainable management option.