Fungal and termite resistance of wood treated by boric acid with tannin

WANG Chen-zhi; ZHAO Fu-lai; PAN Cheng-yuan

Abstract：Objective To determine the resistance of boron-tannin-treated blocks on fungi (Trametes hirsuta) and termite (Reticulitermes chinensis).Methods Sapwood blocks of Pinus massoniana were treated by boric acid with tannin under vacuum,and then leaching test of these blocks was carried out for 14 days to evaluate the retention ratio of boron in blocks.Meanwhile,the capacities of those boron-tannin-treated blocks against Trametes hirsuta decay and Reticulitermes chinensis damage were examined.Results The leaching test showed retention ratio of boron reached 39.21％ after adding tannin into blocks.The mass-loss rate of blocks treated by 2％ and 4％ boron-tannin mixture were less than 5％ after those blocks infected by Trametes hirsute.When the retention ratio of boron in blocks reached 3.10 kg/m3,the mortalities of termite were more than 93％ and the mass-loss rate of these blocks under termite attack was less than 3％.Conclusion Boron retention ratio in blocks could be increased obviously after adding tannin into blocks.Also,boron-tannin-treated blocks exhibited significantly a high resistance to fungi and termite.Though tannin did not affect blocks resistance to termites,it would help the boron fixed in blocks.