Effects of Prescribed Burning on Advanced Regeneration in Upland Oak Forests of Missouri

Seventy years of fire-suppression and inappropriate management practices have resulted in numerous forest health problems in the current oak-hickory forests of Missouri, and have often resulted in the failure to adequately attain oak regeneration. The Chilton Creek Prescribed Burning Project, initiated by The Nature Conservancy in 1996, was designed to study the effects of prescribed fire on oak regeneration. Three different approaches to the use of prescribed fire were tested: annual burning (sites burned each year), random burning (sites burned randomly with a mean return interval of 3.6 yrs), and high-intensity random burning (same as random burn, but with higher fire intensities due to south-facing steep slopes and higher fuel loads) were implemented to monitor the dynamics of advanced regeneration. The presence and condition of regeneration, in terms of tree density and aggregate height, was recorded in 26 permanent plots in 1997 (pre-fire) and again in 2007 (post-fire). Post-treatment red oak densities were reduced by 53, 49, and 26% with the annual burn, the random burn and the high-intensity random burn, respectively. The random burn treatment significantly reduced the aggregate height of hickory compared with the other two treatments – the random burn reduced aggregate height by 83% while the annual burn and high-intensity random burn reduced the height by 40% and 65%, respectively. Preliminary results from this study suggest that increasing fire intensity favors red oak regeneration, although it also favors the growth of hickory. The time since the last burns under each of these treatments likely influenced these results.