A Trial of Fire and Ice: Assessment of Control Techniques for Pyrus calleryana Invasion of Grasslands in Southwestern Ohio, USA

Change in the number of sprouts of Pyrus calleryana from individual stumps in a grassland near Dayton, Ohio, USA. Prior to the beginning of the experiment, these P. calleryana stems had experienced mowing from an industrial mower (“bush hog”) annually for several years and were sprouting. In the negative control (Neg) these sprouts were not cut or treated. In all other treatments, these sprouts were counted, cut, and either no treatment was applied (Cut) or stumps were burned (Fire), frozen with liquid nitrogen (Freeze) or treated with herbicide (Herb). The centerline of the box plot represents the median change in number of sprouts from the pre-treatment survey to the final survey that occurred one year following the treatment applications. Repeated Measures Analysis of Variance indicated a highly significant effect of treatment (p < 0.001) and letters above the boxes represent statistically significant differences indicated by post-hoc pairwise comparisons (all p ≤ 0.05).

Final sprout dry mass of Pyrus calleryana from individual stumps in a grassland near Dayton, Ohio, USA. Prior to the beginning of the experiment, these P. calleryana stems had experienced mowing from an industrial mower (“bush hog”) annually for several years and were sprouting. In the negative control (Neg) these sprouts were not cut or treated. In all other treatments, these sprouts were cut, and either no treatment was applied (Cut) or stumps were burned (Fire), frozen with liquid nitrogen (Freeze) or treated with herbicide (Herb). The centerline of the box plot is the median final dry biomass of aboveground materials of sprouts collected one year after treatment applications. Kruskal-Wallis rank sum test indicated highly significant overall treatment effect (p < 0.001) and letters above the boxes represent differences indicated by pairwise post-hoc comparisons (all p < 0.001).

Total number of sprouts of Pyrus calleryana from individual stumps following various treatments in a grassland near Dayton, Ohio, USA. Prior to the beginning of the experiment, these P. calleryana stems had never been cut or treated and were medium-sized trees. In all treatments, trees were cut at the base and either no treatment was applied (Cut) or stumps were burned (Fire), frozen with liquid nitrogen (Freeze) or treated with herbicide (Herb). The centerline of the box plot is the median number of sprouts at the conclusion of the experiment, one year following treatment application. A Kruskal-Wallis test indicated a strong overall effect of treatment (p < 0.001) and letters represent statistically significant differences indicated by pairwise post-hoc comparisons (all p < 0.001).

Total final dry mass of Pyrus calleryana sprouts from individual stumps following various treatments in a grassland near Dayton, Ohio, USA. Prior to the beginning of the experiment, these P. calleryana stems had never been cut or treated and were medium-sized trees. In all treatments, trees were cut at the base and either no treatment was applied (Cut) or stumps were burned (Fire), frozen with liquid nitrogen (Freeze) or treated with herbicide (Herb). The centerline of the box plot is the median final dry mass of aboveground materials one year following treatment applications. A Kruskal-Wallis test indicated a strong overall effect of treatment (p < 0.001) and letters represent statistically significant differences indicated by pairwise post-hoc comparisons (all p < 0.001).