Blowdown Dynamics in Oak-Hickory Forests of the Missouri Ozarks

• Published in: The journal of the Torrey Botanical Society 2001-10, Vol.128 (4), p.362-369
• Main Authors: Rebertus, Alan J., Meier, Albert J.
• Format: Article
• Language: English
• Subjects: Deciduous forests; Forest canopy; Forest ecology; Forest growth; Forest regeneration; Forest stands; Hardwood forests; Old growth forests; Quercus; Stand management; Understory
• ISSN: 1095-5674; 1940-0616
• DOI: 10.2307/3088668

Several studies in the literature have relied on public land survey (PLS) notes from the 1800's to reconstruct historical blowdown rates in eastern deciduous-conifer forests, but assessment of contemporary blowdown regimes in the region has not received much attention. We used an approach similar to the PLS method, and sampled 105 km of transect to determine whether oak (Quercus) dieback led to extensive secondary blowdown of patches $\geq\!\!500\>m^2$ in 50- to 100-year-old oak-hickory forests in the Missouri Ozarks. Few studies of wind disturbance have focused on even-aged, second-growth stands, even though such stands predominate in eastern deciduous forests. From 1986-1996, blowdowns $\geq\!\!500\>m^2$ disturbed 1.42% of the landscape; for patches 0.05-2.5 ha, only 0.63% of the landscape was disturbed. Although extensive oak dieback occurred in the 1980's and 90's, most of the decline was distributed diffusely through stands, and coarser patches of windthrow were uncommon. Shade-intolerant scarlet oaks (Quercus coccinea Muenchh.) dominated the pre-disturbance canopy and were the dominant treefalls, but two-thirds of new regeneration in blowdowns consisted of white oaks (Quercus alba L.), hickories (Carya spp. L.), and flowering dogwoods (Cornus florida L.). Blowdowns appeared to leave the understory intact, favoring future dominance by species with intermediate shade tolerance.