Population Growth of Pyrus calleryana Culivars and Impact on Native Tree Species on the Campus of Kentucky State University

Pyrus calleryana “Callery Pear” is an invasive ornamental plant species that hybridizes without other pear cultivars such as the “Aristocrat” and “Bradford”. These trees are characterized by rapid growth and weak limbs. Hybrids of these cultivars have recently established on the campus of Kentucky State University. The study estimated the population size and growth rate of P. calleryana on the Kentucky State University Campus over two years and to compare community diversity and species richness of native trees in plots with P. calleryana and plots without the invasive species. Based on an initial survey from 2015, there were two P. calleryana and in 2017, 97 trees within a 1235 m2 area were identified resulting in a growth rate of 48 per year. Native species richness was higher in plots without P. calleryana and were dominated by black walnut, hackberry, box elder, black cherry, and white locust. Soil moisture ranged from 10-51% and soil pH from 5.9-6.2 in the study plots. Four methods of removal will be implemented in each plot respectively with the fifth plot serving as the control. The four experimental removal methods are; pruning, pruning and fabric cover, shovel removal, and chemical treatment. The plants will be removed in late November. The plots will be reexamined in the spring to determine which removal method resulted in the greatest proliferation and diversity of native plant species, also the abundance of P. calleryana in the plots will be recorded to determine which removal method was the most efficient at preventing P. calleryana regrowth. Our study demonstrates the exponential growth and dispersal of these pear hybrids and their impact on native species