Factors affecting branch wound occlusion and associated decay following pruning – a case study with wild cherry (Prunus avium L.)

Pruning wild cherry ( Prunus avium L.) is a common silvicultural practice carried out to produce valuable timber at a veneer wood quality. Sub-optimal pruning treatments can permit un-occluded pruning wounds to develop devaluing decay. The aim of this study is to determine relevant branch, tree and pruning characteristics affecting the occlusion process of pruning wounds. Important factors influencing occlusion time for an optimised pruning treatment for valuable timber production utilising wild cherry are derived. 85 artificially pruned branches originating from ten wild cherry trees were retrospectively analysed. Branch stub length, branch diameter and radial stem increment during occlusion were found to be significant predictors for occlusion time. From the results it could be concluded that for the long term success of artificial pruning of wild cherry it is crucial to ( i ) keep branch stubs short (while avoiding damage to the branch collar), ( ii ) to enable the tree to maintain significant radial growth after pruning, ( iii ) to avoid large pruning wounds (>2.5 cm) by removing steeply angled and fast growing branches at an early stage.