DAHURIAN LARCH - TREATMENT WITH INORGANIC ARSENICAL PRESERVATIVES

The treatability of dahurian larch (Larix dahurica) from Russia was as sessed by commercially treating non-incised dimension material with ch romated copper arsenate (CCA) or ammoniacal copper zinc arsenate (ACZA ). ACZA treatment was generally better than that with CCA, although in neither case did dahurian larch meet the standards specified by the A merican Wood-Preservers' Association for difficult-to-treat wood speci es in ground contact. The use of incising and long vacuum-pressure cyc les similar to those used for Douglas-fir, western larch, and other re fractory wood species should be considered if dahurian larch is treate d with preservatives.