A series of studies were conducted in this project including 1) Evaluating the effect of the wetwood control agent on wood weight loss; 2) Evaluating the effect of the wetwood control agent on wood strength loss; 3) Evaluating the effectiveness of the wetwood control agent on western wood species; 4) Investigating natural distribution of the wetwood control agent in balsam fir logs and lumber; 5) Stimulating natural colonization and enhancing growth of the wetwood control agent; 6) Optimizing biological formulation and shelf life; 7) Studying the feasibility of biological stimulation for natural colonization; and 8) Identifying potential commercial partners, product registration and new substances notification.
The results showed that the two wetwood control isolates were able to cause weight losses of the fresh sapwood of balsam fir, sub-alpine fir and hemlock tested; however, the amount of the weight losses caused by the wetwood control agent was significantly lower than the one caused by the true decay fungi. The wetwood control isolates were unable to cause wood strength loss of treated balsam fir lumber after an outside summer storage of 8 weeks. Both isolates of the wetwood control agent grew well on the western wood species such as sub-alpine fir or hemlock and reduced moisture contents from these wood species.
A total of 456 cultures were isolated from bark of balsam fir logs, 295 cultures were isolated from the wood of logs, and 110 cultures were isolated from sawn lumber. Among these cultures, 2% of the wetwood control agent were isolated from bark, 6% of them were from wood and 5% from lumber. Studies also showed that pre-treating wood with 1% bleach solution or steaming at 100°C for 10 minutes could stimulate the growth of the wetwood control agent on balsam fir wood.
Considering the high efficacy and the low cost, the best formulation of the wetwood control agent was identified as a concentrated spore suspension. Such a formulation could be stored or transported at ambient temperature, at 4°C or at -20°C; however, the highest survival rate was observed from those cultures stored at 4°C, which survived 100% for 3 months and 68% for 6 months. The moisture content loss from balsam fir logs treated with the culture of the wetwood control agent was 43.6% after a 2-month storage period. The potential commercial partners for commercializing this bio-product have been identified.