Wound Compartmentalization in Tree Cultivars: Addendum

Abstract

Fourteen cultivars of Acer (maple), Fraxlnus (ash), Quercus (oak), and Tllia (linden) that have been successfully propagated on a commercial scale by budding or grafting were found to be strong Wall 2 compartmentalizers of chisel wounds made in trunks. This confirms our earlier report of similar behavior in 20 other cultivars in 7 genera. The only exceptions to the strong compartmentalization response were in a Zelkova cultivar in which considerable wood discoloration was present at the time of wounding and in a sugar maple cultivar that became infected with a fungal canker organism in the wound area. Hybrid poplar clones have traditionally been propagated by cuttings, and both strong and weak compartmentalizers were found. There is a strong relationship between strong Wall 2 compartmentalization and the ability of the tree to restrict the amount of wood discoloration and decay following improper flush pruning of branches. Illustrations are also provided to show: (1) that trees that are inherently strong Wall 2 compartmentalizers will still give a strong response even when wounded outside previous wounds and (2) that Wall 2 does not necessarily form at an annual ring.