A method for evaluating the size of damages to fruit trees during pruning using different devices

Abstract

Abstract New methods of pruning are nowadays studied to optimize forming the canopy of fruit trees, as well as maintain an appropriate canopy size and density over time. The most widespread method is traditional pruning by using manual or pneumatic shears or loppers. Mechanical pruning using circular saws, mulching discs, and chain saws is also commonly used, however, there are concerns among some fruit growers to the effects of mechanical pruning. The assessment of size of damages reported in the literature is ambiguous as it depends on a number of factors, such as geographic area, plant species, and pruning technique. Therefore, this paper proposes a method for evaluating the size of damages to fruit tree shoots made by various pruning devices based on fractal dimension analysis of the cut shoots images. The study involved pear, apple, plum, and cherry shoots and four devices: a chain saw, circular saw, anvil lopper, and bypass lopper. It was found that the type of pruning device and tree species had a significant effect on the obtained fractal dimensions. The lowest dimensions, indicating low shoot damage were found for apple and pear trees (in contrast to cherry and plum trees). The damages caused by circular and chain saws were more extensive than that effected by anvil and bypass loppers. Fractal dimension analysis of pruning quality enabled quantitative assessment of each pruning device and species susceptibility to damages. The obtained results contribute to filling a lack of knowledge concerning important aspects of manual and mechanical pruning as well as susceptibility to damage the shoots.