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Educational Sessions

Tree Risk Assessment

The CODIT Principles
Tuesday, 11 August 2015
3:30 PM — 4:10 PM
Osceola Ballroom C
A, T, L, Bs

The contribution describes the complex changes in trees after wounding. Summarily four phases of defense reactions according to the CODIT principle are presented:

Phase 1: Invading air. As a reaction on the invading air the tissue at the wound edges dies.

Phase 2: Invading of microorganisms (e.g. decay) into the dead discolored tissue.

Phase 3: Spread of mircoorganisms in the wood. Especially in older tissue the reaction zone can be breached.

Phase 4: Encapsulation of the microorganisms. Wound closure progressing from the wound edges encapsulates the infected wood. Once the decay is enclosed the microorganisms die since needed oxygen is no longer available to microorganisms.

The encapsulation of wood infected by fungi is the survival principle for trees.

The presentation shows the wound reactions in different tree species and in different types of wounds and gives recommodations for arboricultural practice.

The CODIT principles are based on results of research from different institutions in the world. The concept is published in Germany (Das CODIT Prinzip). The English version will come out in 2015 published by the ISA.

Presenter Information

    • Dirk Dujesiefken

      Dirk Dujesiefken was a research fellow for the Chair for Wood Biology from 1980 to 1991 and has been head of the Institute of Arboriculture in Hamburg since 1991. He teaches at the University of Applied Science (HAWK) in Göttingen, Germany, at the Swedish University of Agricultural Science (SLU) in Alnarp, Sweden, and at the University of Natural Resources and Life Sciences (BOKU) in Vienna, Austria.

      Institute of Arboriculture, Hamburg, HH, Germany