Municipal bio-solids to enhance tree growth After two years of study the municipal bio-solid siliviculture experiment is moving to commercial application. Research into the use of bio-solids as organic tree fertilizer began at the Whistler interpretive forest in 1992. The bio-solids, taken from the municipal sewage plant after they have been treated, can be used in place of chemical fertilizers. On Tuesday, council approved the first year of a five-year program that will see municipal bio-solids used to fertilize trees, initially in the Lower Callaghan Valley and later in the Whistler Interpretive Forest. Both areas are slated for fertilizer application, but normally it would be done with a chemical fertilizer, like urea. The municipality has submitted an application for Forest Renewal B.C. funding and a draft permit application to the Ministry of Environment, Lands and Parks to carry out the fertilizer application. The unique program — it is the first time in B.C. bio-solids have been used in this way, on this scale — could potentially consume all the bio-solid waste produced by the municipal sewage plant. The program was studied by foresters and scientists from 1992 to 1994. Researchers found optimal application rates which, together with spacing and pruning of trees, increased the volume of timber that could be harvested. Researchers also monitored the impact of bio-solid applications on the Cheakamus River. In general, they found a rate of application which "caused beneficial growth in trees with no significant impact on adjacent water bodies," according to a memo from the director of public works, John Nelson. Much of the work and treatment of the bio-solids has to be done regardless of whether or not the material is used for fertilizer. Nelson says the fertilizer application will only cost the municipality about $30,000 annually. The municipality could eventually be faced with paying to get rid of the bio-solids if the material isn't used as fertilizer. Also, the material could become well recognized as a fertilizer and the municipality may some day be in a position to charge for treated bio-solid material. As well, the forest in the Lower Callaghan is slated to be harvested many years from now. When harvesting does occur the forestry company could pay the municipality for increased yields, due to the fertilizing.