PRESERVATIVE TREATMENT OF RED MAPLE

The development of additional preservative treatments for underutilize d eastern hardwoods, such as red maple, is critical to the development of new market opportunities that require long-term utilization of har dwoods in exterior structures. This project investigated the treatabil ity of red maple sapwood and heartwood with water, toluene, CCA (chrom ated copper arsenate), ACQ (ammonium copper didecyldimethylammonium ch loride), creosote, and toulene- and waterborne copper naphthenate. The efficacy of CCA, and of water- and oilborne copper naphthenate agains t a brown-rot fungus (Postia placenta), a white-rot fungus (Trametes v ersicolor), and a soft-rot fungus (Chaetomium globosum) was also deter mined using sapwood blocks in agar block decay tests. Substantial diff erences were found between heartwood and sapwood treatability. Full-ce ll impregnation resulted in sapwood samples being thoroughly penetrate d and consistently treated to retentions of 30 to 40 pcf (lb. solution /ft.(3) wood). Preservatives penetrated heartwood only about 3 mm tran sversely and 15 mm longitudinally. Retentions ranged from 5 to 15 pcf. On an equivalent copper loading basis, the oilborne copper naphthenat e was more effective than the waterborne formulation against white- an d soft-rot fungi. CCA protected maple sapwood against brown- and white -rot fungi at low retentions, 0.1 percent copper weight/weight. Simila r to past work, however, higher loadings were needed for soft-rot prot ection.