Investigation of the potential for bark patch grafting to facilitate tree wound closure in arboricultural management practice.
Grafting and budding are common horticultural techniques, and similar techniques have been successfully used in the management of tree wounds by bridge and approach grafting. The success of bark grafts raises the possibility of using bark patch grafts to span trunk wounds and pruning cuts. Fifty seedling trees from each of six commonly planted Australian native and exotic species - Acacia dealbata, Banksia integrifolia, Eucalyptus viminalis, Platanus × acerifolia, Quercus robur, and Pinus radiata-had circular plugs of bark removed from their stem using a #3 cork borer (9 mm diameter). The plugs were lifted from the stem and then re-attached at one of four rotations (0, 90, 180, and 270 degrees) to the original cambial orientation in each of the four seasons. While there was no successful re-attachment for Pinus radiata, the data for the successful re-attachment of the other five species showed that the most successful orientation for re-attachment was in the original position (0 degrees); successful attachment did occur at other orientations. The best season for re-attachment was spring, but successful attachment did occur in other seasons; success was lowest when grafting was undertaken in winter. The use of bark patch grafts may provide arborists with an additional method for dealing with large wounds caused by vandalism and accidents, and would be particularly useful if a tree was of special, historic, or environmental significance to the landscape. Covering the wound with a bark patch graft may conceal the removal of a branch, hide obvious scarring, and at the same time reduce the risk of disease and stress to the tree by closing the wound more quickly than would normally occur due to natural callusing.