Using Fire to Regenerate Oak After Clearcutting

Prescribed fire can be used to regenerate oak after clearcutting. Vigorous, abundant sprouting of oaks occurs following broadcast burning of clearcut areas (Van Lear and Watt 1993). Burning of clearcut hardwood or mixed pine-hardwood stands promotes better quality oak sprouts by forcing them to develop from the groundline. Over 97 percent of all oak sprouts developing after broadcast burning of logging slash in the southern Appalachians were basal sprouts, versus 71 percent for unburned areas (Augspurger and others 1987). Suppressed buds higher on the stump are apparently destroyed by the intense heat of the fire. Sprouting from buds at or below groundline is encouraged by fire, reducing the likelihood of rot being transferred from stumps to new sprouts (Roth and Sleeth 1939). Poorly formed tops of small (<15 cm) oak stems killed by fire are replaced by more desirable sprouts, which are more likely to develop into sound timber trees than other types of oak regeneration (Roth and Hepting 1943, Teuke and Van Lear 1982).

Many questions remain unanswered regarding the effects of broadcast burning on stem quality of regenerating oak stands. Some research suggests that fire may cause multiple sprouting from top-killed advance regeneration (McGee 1979 in Van Lear and Watt 1993). In addition, some rootstock may be damaged or even consumed by fire, thereby reducing the regeneration potential of the stand. However, observations of dozens of hardwood-pine stands regenerated using the fell-and-burn site preparation technique (Abercrombie and Sims 1986) suggests that broadcast burning under carefully prescribed conditions is favorable to quality oak regeneration in the southern Appalachians.

Intense fires can sometimes result in the introduction of oak in the succeeding stand (Van Lear and Watt 1993). Nowacki (1988) documented cases in northern Wisconsin where clearcutting of old-growth maple-hemlock stands and slash burning resulted in even-aged stands dominated by northern red oak. Lorimer (1989) suggested that these oak stands probably developed from acorns brought into the burned area by birds and animals. Similar observations have been made following an intense wildfire in the mountains of South Carolina. However, in some cases, intense fires may have unintended effects. For example, Loftis (1990) found that a severe backing fire killed oak seedlings in northern Georgia, and opened microsites for yellow-poplar seedlings.