Copper-chrome-arsenate (CCA) preservatives have been use extensively in New Zealand since the mid-1950s for a wide range of ground contact uses, radiata pine being the main species treated. They have been the subject of a comprehensive field testing programme in up to five sites in New Zealand, the earliest tests being established in 1955. Main factors affecting performance have been formulation type, test site and test specimen size. In nearly all tests where efficacy of CCA has been compared with other preservatives, CCA has been more effective in controlling decay, particularly on drier sites. In a warm and wet site (annual rainfall 2,000 mm) where soft rot and brown rot predominate, there has been very little difference in performance between CCA and other multi-salt formulations, but in a very wet site (annual rainfall >3,500 mm) CCB and CCP have out-performed CCA.

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