I have one more comment to add to the alternative fiber debate. In performing the cost/benefit analysis of annual fiber crops vs trees, ecosystem function should be considered. Each harvesting operation will have the effect of reducing nutrient pools in the system, reducing organic matter in the soil, and compacting the soil. The long-term effect of annual harvests vs harvests every 40 to 120 years for forests or tree plantations will be very different. The rotation age of forests is much closer to the time scale of nutrient turnover due to weathering, leaching etc. than an annual cycle. Buildup of OM and decompaction are also processes requiring years or decades. In many cases, the ecosystem cost of annual cropping, although more difficult to determine than other costs, might tip the balance in favour of trees for fiber. #---------#---------#---------#---------#---------#---------#---------#------/ James D. Stewart (stewartj@gpu.srv.ualberta.ca) Edmonton, Alberta Department of Renewable Resources T6H 2H1 Canada University of Alberta (403) 492-6827
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