Epicormic development in pole-size white oak (Quercus Alba L.) progeny tests three years following crown releaseThis article is part of a larger document. View the larger document here.
Epicormic development has been traditionally thought to be a response to increased light and to varying vigor and genetics among individuals within a species, but epicormic ontogeny has increasingly been shown to be a more fundamental factor. Previous studies have quantified the impact of tree vigor on epicormic sprouting and epicormic branch size following silvicultural treatments, but few assessed the genetic component of development. In this study, data from a crop tree release treatment in a 25 year old white oak (Quercus alba L.) progeny test in Indiana was used to isolate the relative influences of tree vigor and progenylevelgenetic variation on epicormic development. We found no significant difference in the total number ofepicormic branches three years following crop tree release (p = 0.940), but a significant increase in epicormic branch size (p < 0.001). Variation explained by family effects was stronger for branch size than for branch numbers, but provenance did not improve fits for any model. Tree vigor-related variables were significant predictors in all models, but the epicormic response was driven most strongly by pre-treatment epicormic composition. Therefore, a major objective in the management of young oak stands should be to maintain tree vigor to avoid the initial sprouting of epicormics and to remove individuals with many epicormics early in the rotation.