Abstract:
Woody plant expansion into grasslands and savannas is a globally occurring phenomenon that has considerable economic and socio-cultural impacts. I use a multi-site historical study to quantify age structures of Quercus marilandica (Blackjack Oak) and Quercus stellata (Post Oak) from four discrete Cross Timbers stands in the Chautauqua Hills Region of southeast Kansas. My objectives are to determine when expansion occurred and from which landscape position oaks have expanded. Finally, I examine how timing and spatial patterns of expansion differ between species in the White and Red Oak subgenera. Preliminary data from the first site indicates an even-aged stand structure, represented by a normal distribution among age classes. Mean age for Post and Blackjack oak are 34 and 42 respectively and, maximum ages are 70 and 82 respectively. The relationship between tree age and landscape position was assessed by using slope position categories (mid-slope, ridge, and drainage) and slope steepness (degrees). There was no significant relationship between these two categories and tree age. However, sampling three more sites will provide further insight into the effect of landscape position on the two oak species in the Chautauqua Hills, KS. and should reveal any regional patterns that exist.
