Abstract:
Kumi-Woode, B. G. 1996. Natural decay resistance of some Ghanaian timbers and wood decay
hazard potential for Ghana. M.Sc.F. Thesis. Faculty of Forestry, Lakehead University,
Thunder Bay, Ontario, Canada. 98 pp. (Advisor: E. C. Setliff, PhD).
Key words: decay resistance, agar-block, soil-block, Coriolopsis polyzona, Oligoporus
placentus, Pycnoporus sanguineus, Trametes versicolor, decay index.
The natural decay resistance of 30 Ghanaian wood species, the decay capacity of four
wood decay fungi, the effect of test method on fungal decay ability, and the wood decay hazard
potential in Ghana were determined. Five of the wood species were rated as highly resistant,
six as resistant, eight as moderately resistant and 11 as non resistant. Of the four decay fungi,
Coriolopsis polyzona, Oligoporus placentus, Pycnoporus sanguineus and Trametes versicolor,
only the strain of C. polyzona (004) induced adequate weight loss in the birch reference wood in
either test methods (agar- and soil-block) for use in decay resistance rating. The two methods
significantly influenced the performance of the fungi after 6 weeks of exposure with the white rot
fungi showing higher decay ability in soil- than agar-block method, the converse was true for the
brown rot fungus (O. placentus) using Betula alleghaniensis as substrate. However, after 12
weeks of exposure the test methods did not seem to have any effect on the performance of the
fungi and resultant decay rating. Wood decay hazard in Ghana varies from areas of moderate, to
those of very high potential. Generally the western part of the country has higher hazard
potential than the eastern portions and the south has higher potential than the north, except for
the southeastern comer which has the lowest hazard potential. Rainfall amounts, and to some
extent the relief of the area, were the paramount determinants of the decay index in Ghana rather
than temperature.
