Five-year field trials using preservative-treated, second-growth Douglas-fir exposed in ground contact in Australia

The durability of preservative-treated stakes of second-growth Coastal Doug las-fir was evaluated in a field plot in northern Queensland, Australia. Re sults from this field trial indicate that second-growth Douglas-fir can be treated with preservatives to meet Australian standards and will provide lo ng-term durability in adverse environments. Data presented indicate that wi thin a 5-year time frame, the importance of minimum penetration parameters decreases as retention increases.