A Trial of Fire and Ice: Assessment of Control Techniques forPyrus calleryanaInvasion of Grasslands in Southwestern Ohio, USA

Abstract

<h3>ABSTRACT</h3> <i>Pyrus calleryana</i> (Callery pear) is an invasive plant that threatens ecosystems in the eastern United States. We investigated the efficacy of various control techniques on <i>P</i>. <i>calleryana</i> invasion in grasslands. Treatments were applied to (a) <i>P. calleryana</i> stems that had experienced mowing annually for several years and were sprouting (<i>n</i> = 100 stems; “trees-sprouting”) and (b) stems that had established ca. 10 years earlier, had never been cut, and were single-stemmed trees (<i>n</i> = 40 stems; “trees-intact”). In both experiments, existing stems were cut and randomly assigned one of the following treatments: cut only (control), burning, freezing, or herbicide, and in the trees-sprouting experiment there was also a negative control of monitoring existing sprouts. All trees in which the cut stumps were treated with herbicide were effectively killed, whereas stems in all other treatments, in both experiments, generated a vigorous sprout response. In the trees-sprouting experiment, there was a strong overall effect of treatments (RMANOVA; <i>p</i> &lt; 0.001) and prescribed fire created a statistically significant increase in sprout number in relationship to the negative control (<i>post-hoc</i> test; <i>p</i> = 0.036). In the trees-intact experiment, there was vigorous sprouting in response to all treatments other than herbicide. Stump freezing resulted in a delay in sprout response; however, all frozen stems eventually sprouted. The ability of this species to sprout vigorously, even after experiencing frequent and intense ecological disturbance, creates the potential for a fundamental alteration of old-field succession in habitats where this species is present.