Age estimation of Quercus marilandica and Quercus stellata:: applications for interpreting stand dynamics

We compared methods to correct age of cores that failed to intercept the tree's pith for two oak species, blackjack oak (Quercus marilandica Muenchh.) and post oak (Quercus stellata Wangenh.), and determined the difference in age at tree base (0-10 cm from ground level) versus breast height (1.4 m from ground level). Methods to correct age of off-center cores were relatively similar in error for both species (2.9-8.1 years). Ocular estimation of number of rings to pith required the least amount of data collection and manipulation to apply. A regression technique using tree diameter provided the lowest absolute error (9-13 years) for age estimation of rotten cores, compared with methods that used mean ring widths to extrapolate tree age. Age difference due to coring height averaged 9 years for both species and was highly variable, indicating that trees should be cored as close to ground level as possible. Age structure of this forest could be accurately reconstructed to within 5-year age-classes using recommended methods, with the exclusion of large, rotten, and putatively old trees.