HISTOLOGIC INVESTIGATIONS OF THE PROTECTION WOOD OF INDIGENOUS HARDWOODS

The protection wood underneath a total of 76 artificially produced stem injuries (shallow wounds) afflicted on 7 different indiginous hardwood species were investigated macroscopically and under the microscope. Histologic alterations which occur in wood tissue formed prior to the injury on account of damage to the cambium as well as species related differences in protection wood formation in the hardwoods are described. Independent of species related differences effectivity and extent of the counteraction seem to be strongly influenced by the type of injury (shallow wounds or injury caused by increment borers). The concept of "protection wood", displaced by the CODIT-model, and originally coined by Frank (1884) is being discussed. The authors come to the conclusion that the old term is suited to the description of wound reactions within the wood formed prior to injuries. Within the protection wood three distinct zones have to be differentiated, namely the desiccation zone, the dis-coloration zone proper and the surrounding marginal zone.