The effect of cutting technique on the mortality and resprouting vigor of hybrid poplar stumps

Short rotation coppice is a modern industrial crop, and its profitability depends on the mechanization of all management operations. Once the crop is mature, trees can be felled with a variety of machines, but shears represent the most effective solution. However, shears can inflict a certain degree of stump damage, which has raised concerns about stump mortality and resprouting vigor, both crucial to coppice regeneration. This study, conducted on five sites in western Slovakia, compared the mortality and resprouting vigor of stumps cut with shears and with chainsaw, the latter representing the control treatment. Measurements were taken on six compartments across these sites. In each compartment, between 9 and 10 sample plots were established, each consisting of two parallel row segments containing 10 live stumps (20 stumps per plot). One row segment was cut with a shear-type felling head, the other with a chainsaw-type felling head. One year after cutting, we assessed stump diameter, number of live shoots, and diameter and height of the five tallest shoots. Data were pooled into a structured database and statistically analyzed using R. Site fertility had a very strong effect on resprouting vigor. Cutting technique had no effect on stump survival and only a minor effect on resprouting vigor, with shear-cut stumps producing a slightly larger number of shoots. Although not statistically significant at the selected α-level, data suggested that the five dominant shoots on shear-cut stumps might grow slower due to stronger intra-stump competition, particularly on less fertile sites.