Oak regeneration and overstory density in the Missouri Ozarks

Abstract: Reducing overstory density is a commonly recommended method of increasing the regeneration potential of oak (Quercus) forests. However, recommendations seldom specify the probable increase in density or the size of reproduction associated with a given residual overstory density. This paper presents logistic regression models that describe this relation for a forest in the Ozark Highlands of Missouri that has been managed for 40 years by the single-tree selection system. In general, density of oak reproduction of a given size increases with decreasing residual stand basal area. However, the corresponding increase in the reproduction density at all levels of overstory density indicates low predictability of individual stands. The models nevertheless describe the average trend in the highly stochastic regeneration process. They also suggest that stand densities must be kept low (e.g., basal areas <14 m2⋅ha1) to sustain the requisite recruitment of reproduction into the overstory under the single-tree selection method. Résumé: La rØduction de la densitØ du couvert est une mØthode communØment recommandØe pour augmenter le potentiel de rØgØnØration des forŒts de chŒnes (Quercus). Toutefois, les recommandations spØcifient rarement laugmentation probable de la densitØ ou de la taille de la rØgØnØration associØe à un niveau donnØ de densitØ rØsiduelle du couvert. Cet article prØsente des modŁles de rØgression logistique qui dØcrivent cette relation pour une forŒt des plateaux de lOzark, au Missouri, qui a ØtØ amØnagØe depuis 40 ans sous un rØgime de futaie jardinØe par pied darbre. De façon gØnØrale, la densitØ de la rØgØnØration de chŒne dune dimension donnØe augmente avec une rØduction de la densitØ rØsiduelle du couvert. Cependant, laugmentatio