Wood properties of trees irrigated with sewage effluent in relation to their suitability for fence posts.  R. J. McKimm.  September 1983.  16 pp. (unpubl.)

SUMMARY

Posts and wood samples from plantation-grown trees, almost four years of age, irrigated with sewage effluent at Mildura, Victoria, were tested for basic density, strength properties and preservative absorption.

The full range of tests were made in Eucalyptus grandis W. Hill ex Maiden (flooded gum) and E. botryoides Sm.(southern mahogany), whereas only density measurements could be carried out on Casuarina cunninghamiana Miq. (river she-oak) because of severe splitting of the post sections on drying. It is unlikely that marketable roundposts can be produced from trees of this species grown under such conditions.

The proportion of sapwood trees of all three species was found to be high, and density values were considerably lower than those for the heartwood of butt logs from mature trees of the same species. However, measurements of maximum load and modulus of rupture showed that strength properties of the two eucalypts were sufficiently high for posts of these species to meet any strength requirements for fencing.

The sapwood of both eucalypts was found to be easily and uniformly penetrated under pressure with either CCA or creosote preservatives. Sap replacement treatment, on the other hand, although producing adequate retentions, gave variable penetration patterns.

Also published:

McKim, R.J. (1984)  Fence posts from young trees irrigated with sewage effluent.  Aust. For. 47 (3): 172-8.