Effects of cutting patterns of shears on occlusion processes in pruning of high-quality wood plantations

Arboriculture plantations aim to produce high-quality wood. In order to investigate the type and extent of mechanical injury that pruning causes to tree cambium as well as the effects on the healing process, different types of shear were selected and used in an eight-year-old Quercus robur L. plantation. The amount of removed, detached and crushed bark was assessed by means of image analysis immediately after pruning. After 15 months, the effect of different cutting patterns on the healing process was investigated by measuring the area of the pruned branch covered by woundwood (HI1). Five years after pruning, the same analysis was performed above and below bark (HIo5 and HIu5) and a number of parameters were assessed in order to quantify the quantity and quality (symmetry) of woundwood growth and the healing time for sealing. The action of pruning tools depends on cutting pattern and branch diameter. The greater the diameter, the longer the healing time. The double-blade tool caused less injury and showed the fastest healing process. The use of double blade pruning tools is thus recommended to improve the performance of wood quality production in arboriculture plantations. We also recommend the healing index HI1 for an early assessment of pruning damage.