Norm; I was specifically commenting on biomass and nutrients, not species diversity or the possible effect of clearcutting on some potentially critical but largely unquantified mechanisms of nutrient supply to trees. These are potentially compelling, but largely unquantified and unproven. Biomass removal, however, is largely quantified in terms of nutrients. Biomass removal does not generally depauperate the entire ecosystem, and I gave specific examples of that for Pacific Northwestern Douglas-fir. No study that I know of has shown that clearcutting itself makes nutrients largely unavailable to trees, either by removing the bulk of them, or turning them into an unavailable form. Please don't quote the Hubbard Brook study as an example of nutrient loss by clearcutting since it also involved complete devegetation for a number of years with herbicides. There were also a lot of nutrients remaining in the ecosystem even following that extreme treatment. In most cases, new forests can be established and grown from clearcuts just fine. I don't know of any failures at new stand establishment that are due to nutrient loss from biomass removal. That is more likely to be a long-term factor of short rotation, intensive forest culture. Then it is possible to replace the nutrients by fertilization. There certainly are examples of stand establishment failures due to fire, disease, insects and weed competition, and to extreme weather conditions such as frost or extreme drought. Ice was a particular problem in this region a couple of years ago. Norm Cimon wrote: > > Your discussion may be missing an important point: the microflora and microfauna > which act as the intermediaries of the nutrients to the trees. There was a lot of > interest in the early and mid-80s in the Pacific Northwest in the role of downed > rotting logs as a repository for these organisms. My own impression is that the > forests are really tri-partite: trees, nutrients and a way to go back and forth > between them. >
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