Evaluation of tree damages after injection treatment
1991
Wichmann, C. (Biologische Bundesanstalt fuer Land- und Forstwirtschaft, Braunschweig (Germany). Inst. fuer Pflanzenschutz im Forst) | Wulf, A. | Kehr, R.
Tree injections are increasingly being used in order to introduce systemic plant protection agents into the sap stream of trees. Besides having advantages, such as safe application, there are also disadvantages, especially wounding of bark and sapwood. In order to test the effects of a Swiss-made injection apparatus, 46 trees of 12 important forest species were injected in the lower trunk during spring. After one growing season, the tree reactions and microbial colonization of the affected tissues were registered. It was demonstrated that an injection treatment can cause bark and wood cracks, necroses of bark and cambium and mainly longitudinal discoloration of the wood, depending on the tree species and individual vigour. After six months, the wound region and discolored wood was colonized by a number of fungal species, mainly ascomycetes and deuteromycetes, some of them being able to cause soft-rot. Due to extensive necrosis and discoloration and therefore loss in timber value, which would be aggravated by successive treatments, this injection method cannot be recommended for forest trees. Taking into account the benefits, risks and possible fields of application, the method is, at present, also not judged suitable for urban trees
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