David; Did I miss something here, or are you just wrong...what do you mean by the term "biomass" here. Is soil part of the forest? Many forests, particularly in colder climates, have most of their carbon and nutrients stored in the soil, not in the trees, and much of the carbon is not living if living is defined as part of a living organism. However, soil can certinly be defined as "living". Old growth forests in the Pacific Northwest typically don't have most of the carbon or nutrients stored in the trees. In the vast majority of cases, the bulk of the nutrients in this region are not in the bole portion of the tree either, but in roots, foliage, bark and branches. Removal of the stems of trees alone cannot "depauperate" the ecosystem of nutrients since such a small amount of those nutrients are in the stems. However, even the loss of a small portion of nutrients can lead to lowered productivity as measured by forest growth rates. Most of our forests are naturally deficient in one or more nutrients, and respond to the addition of limiting nutrients by growing faster. In my mind, a nutrient is a nutrient, whether it comes into the forest ecosystem "naturally" or by being applied from a helicopter. Can you distinguish between a natural and man-applied nutrient in any way (short of isotopic ratios) after they are utilized by a growing tree? It makes sense to replace nutrients that are lost through harvesting, and it makes sense to apply nutrients where they are limiting. After all, this country will need to grow more wood on each acre of managed forest in the future in order to compensate for a reduced acreage available for producing wood. Incidently, I have no argument with your observation that actions such as girdling trees or mortality by burning can be very different than removal. However, I disagree with your generalization that normal biomass removal (i.e. logs) depauperates a forest ecosystem of nutrients since this is simply not true in the vast majority of forests I've studied from the Pacific Northwest to the south of Brazil. ****************************************************** Robert B. Harrison Dept. of Ecosystem Science 206-685-7463 voice & Conservation 206-685-3091 fax Box 352100 Univ. of Washington Seattle WA 98195-2100 mailto:RobH@u.washington.edu http://weber.u.washington.edu/~robh/Faculty/RobCV.html ****************************************************** DavidOrr wrote: > > Hi Greg, > > Thanks for your reply. I am glad to know the USAF doesn't support chemical > management. Will you please explain this to the Forest Service? :-) > > I appreciate your effort to consult widely on a management strategy, too. > That is unfortunately seldom done by other government land mgmt agencies. > > Your dichotomous choice, though, is problematic for me. You say either we do > nothing, or we use a sledge hammer. I don't see it in black and white terms. > > For example, you mentioned girdling in your earlier post. That approach does > not remove the biomass (and here dead wood is also biomass), and the dead > trees provide ecological habitat structure and a longer term opportunity for > cavity nester habitat. Dead wood will be fuel for future fires as well. This > is not what I'd call a sledge hammer management style! > > Biomass removal depauperates the ecosystem from the nutrients stored in the > material. In some ecosystems, nutrients are unnaturally high, as in a > hydrilla-infested watercourse. But second growth forests are rarely > overburdened with biomass, although the form it's in may not be beneficial to > ecosystem function. > > An old growth forest, for example, has its biomass stored in large trees. > Young forests have biomass in dense stands of small trees. Fires tend to burn > the young trees, and this recycles minerals and other nutrients to the soil. > Chipping simply removes the biomass, and it is never again available to the > system for storage or recycling. > > So, if you have to remove the hardwoods, I vote for girdling. But please > inventory your species first, and avoid killing native trees if at all > possible! > > David Orr
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