Improving Competitive Status of Oak Regeneration Using Stand Management and Prescribed Fires

Abstract

The effect of prescribed fire characteristics and timber harvest treatments on top-kill and resprouting in northeastern deciduous hardwood forests was compared among species groups (oak, maple, birch) and size classes to determine if the competitive status of oak regeneration could be enhanced. Prescribed fires were completed in three distinct stand structures (treatments): recent shelterwoods, recent clear-cuts, and stands with significant mountain laurel understories. In each burn, fire behavior was monitored on three to eight plots (15 m × 15 m) using thermocouples arrays. All stems ≥ 140 cm tall within each plot or ≥ 6 cm dbh within 15 m of plot centers were examined for girdling and the number and height of new sprouts during the second growing season after the fire. Top-kill did not vary among species groups and could be described by a logistic function that included treatment, initial stem size, and maximum temperature. Apparent top-kill increased with thermocouple maximum temperature, decreased with stem size, and increased from shelterwood to clear-cut to mountain laurel understory burns. Proportion of top-killed stems with new sprouts was greatest for mountain laurel and oak. A combination of stand manipulation and prescribed fire can improve the competitive status of oak seedlings by modifying regeneration composition and height distribution.