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think that it is prudent at some point to stop and consider what 

 it is we are trying to rehabilitate, what it is that we want to re- 

 store. 



Chief Robertson, I thought, made some important remarks re- 

 garding what it is that ecosystem management is to be, and one 

 of the important things he said it was to be is a change in the way 

 business is done in order to maintain biological diversity across the 

 forests. 



In my book, maintaining biological diversity is going to require 

 restoring the habitat that supports biodiversity, and in terrestrial 

 systems habitat means vegetation. Vegetation is a very complex 

 construct that actually involves much more than just trees, so 

 while planting trees can bring us a long way towards restoring 

 vegetation, it cannot be all that we look at. 



The character of vegetation is as much affected by disturbance 

 as it is by things that we ordinarily consider as determining vege- 

 tation, like climate and soils and the species involved. Factors like 

 wind, flood, and fire can determine whether vegetation is forest, 

 shrub land, or grassland. 



Human beings tend to have their greatest influence on vegeta- 

 tion through their influence on disturbance, and in the Pacific 

 Northwest we are starting to realize that the disappearance of old 

 growth Douglas fir forests is essentially the result of increasing the 

 frequency and intensity of catastrophic disturbance in the form of 

 clear-cutting on the east side, which we have also discussed at 

 length today. 



Fire suppression, another change in disturbance cycles, as re- 

 sulted in the growth of firs and Douglas firs into the forests where 

 fire once excluded them, and their presence now threatens to 

 change the entire disturbance dynamic of those forests. 



So it is now clear that in order to avoid catastrophe and rehabili- 

 tate natural ecological systems will restore to the landscape the 

 disturbance patterns with which the native biota evolved. In some 

 places this will require dramatically reducing the amount of wood 

 we can expect to produce fi-om the site. It will also likely require 

 the use of prescribed fire, reduction in grazing, and limitations on 

 visitor use. In some places, it will require allowing what have tra- 

 ditionally been considered catastrophes, such as fires and floods, 

 the space they need to run their course. None of this excludes hu- 

 mans from the ecosystem, but it will require a dramatic change in 

 the way we view our relationship with it. 



The Pacific Northwest is actually one of the best understood re- 

 gions in the country in terms of natural disturbances, and an ap- 

 preciation for the role of disturbances has allowed scientists to ex- 

 plore means of mimicking natural disturbance in forest manage- 

 ment. New forestry relies heavily on leaving large quantities of 

 wood following harvesting as a direct attempt to mimic the post- 

 disturbance environment. Elsewhere, experimentation with pre- 

 scribed fire has shown that fire cycles can be restored through 

 management. Further improvement in these methods promises to 

 allow society to benefit from the products of the forest without de- 

 stroying its means to produce. Federal investment in these meth- 

 ods would allow us to continue to rehabilitate and reforest long into 

 the future. 



