Effects of seasonal prescribed fire on oak reproduction in stands impacted by oak decline in the Ozark National Forest

The Ozark and Ouachita Mountains of Arkansas have been impacted by oak decline, which has resulted in high mortality rates for several red oak species.  Following a region wide drought in 1998-2000, red oak borer (Enaphalodes rufulus) outbreaks degraded over 300,000 acres in the Ozark National Forest.  Suitable oak reproduction is vital to the regeneration of these degraded upland oak stands.  A field study was conducted in the Ozark National Forest to evaluate the effects of growing and dormant season understory burns on reproduction in degraded stands.  Six months after a dormant season fire, total and northern red oak seedling density increased by 62 and 72 % respectively.  Prior to the dormant and growing season fires, where possible, 5 oak, red maple, and blackgum seedlings were permanently marked in each of 6 plots.  All of the marked seedlings were top killed by the dormant season fire but, by the end of the 1^st growing season following the fire 60% of oak seedlings had grown at least one living sprout >2’ in height.  A total of 88% of seedlings were top killed by the growing season fire; however, only a small proportion exhibited sprouts taller than 6” at the end of the growing season.  A total of 66% of the measured saplings and midstory trees (dbh 0.6 to 4.5”) were top killed by the dormant season fire.  Stump sprouting densities were highest in the 1 and 2” dbh classes.  These trees had an average of 4.7 sprouts per stem.