Controls on Shumard Oak (Quercus shumardii) Establishment into the Cross Timbers Ecotone of Oklahoma: Implications for Restoration

AbstractTo better understand how the Cross Timbers ecotone between U.S. eastern deciduous forest and tallgrass prairie is organized and maintained, I set out seedlings of Shumard oak (Quercus shumardii) for 1 year with treatments of water addition, trenching in pots to reduce belowground competition, burning, and patch type. I found that (1) seedlings in pots survived twice as much as those without pots and seedlings in unburned areas survived up to four times as much as those in burned areas; (2) seedlings in pots grew twice as fast as those planted directly in the soil without a pot; and (3) whereas adding water, planting in a pot, and planting under shrubs all increased leaf chlorophyll absorption, it was when the seedling was watered, under a shrub, or in a pot that chlorophyll increases were 2‐fold. Results suggest these management and restoration strategies to increase Cross Timbers oak establishment: first reduce belowground competition by the resident grasses; second, do not burn; and third, use shrubs as a facilitating tool. Adding water to tree seedlings should be used as a management tool only after others have been tried and failed. Finally, an ecotone conceptual vegetation model is presented both to incorporate the results and to explain how ecotones may be managed, restored, and maintained.