| The recent decline and mortality of red oaks, notably two of the most economically important tree species in southeastern Missouri, is investigated with respect to past disturbance and stand development. Dendrochronology, the measurement of tree rings, provides a view into past growth, often determining current tree-vigor. Red oak stands are tolerant to numerous stresses when young but become increasingly susceptible to drought and shoot dieback after age 50. Recent droughts and Armillaria root disease have caused red oaks to incur mortality, a recent loss of 20--50% canopy cover in many stands. Various site factors are shown to significantly predispose red oaks to drought and dieback. Additionally, the fastest growing red oaks are often more susceptible to drought and permanent growth losses. Sites previously dominated by shortleaf pine often have the greatest dieback and mortality. Without major disturbance, white oak will gradually replace much of the recent red oak dominance within the historic shortleaf pine range of the Missouri Ozarks. |
