Copper-chrome-arsenate (CCA), copper-chrome-boron (CCB), copper-chrome-fluoride (CCF) and copper-chrome-phosphate (CCP) have been tested at four retentions each in ground contact (25 x 50 x 500 mm³ radiata pine sapwood stakes) for 16 years in five test sites in New Zealand. Results to date show that test site characteristics have a marked effect on relative performance. In a warm and wet site (annual rainfall 2000 mm) where soft rot and brown rot predominate, there is very little difference in performance between formulations at equivalent total active element retentions. In drier sites (annual rainfall 1250-1500 mm), where brown rot is more active, CCA is significantly more effective than the other formulations and in a very wet site (annual rainfall >3500 mm) CCB and CCP are most effective formulations. Results are discussed in relation to how climate and soil characteristics influence composition of the fungal flora and their combined effects on preservative efficacy.

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