Effect of Chemical Presevatives on Service Life of Selected Wood Species Treated against Pests and Diseases

摘要

The effect of different chemical preservatives on service life of selected wood species was evaluated in a field plot at the Forestry research site, University of Uyo, Akwa Ibom, Nigeria. Three wood species, Triplochiton scleroxylon K. Schum (Obeche), Gmelina arborea Linn (Gmelina) and Terminalia ivorensis A Chew (Idigbo- Black afara) were used for this study. Two chemical preservatives namely; acid copper chromate and copper citrate at concentrations of 0%, 0.37%, 0.75% and 1.5% each and a mixture of the two preservatives (mixed preservative) at the given concentrations were used in treating stakes of these wood species and their retentions determined. Service life of the stakes was evaluated at the end of six months and insect pest and fungi that infected them identified. The result indicated that obeche had the highest mean retention of 4.04 kg/m 3 .The result also showed that the retention increased with increase preservative concentration, the highest retention of 6.80 kg/m 3 was obtained with mixed preservative at 1.5% concentration. Treated stakes of all the three wood species lasted for the six months of the experiment while the untreated stakes failed within the period. Highest service life rating of 10 (no termite ( Cryptotermes cavifrons Bank) damage) and (-) (no fungal growth) was obtained with mixed preservatives at 1.5% concentration. Based on these findings the use of these preservatives at concentrations of 0.075%- 1.5% to enhance service life is recommended.