Thanks for the very thoughtful responses to my question.

In regard to the question about weeds and toxic chemicals:  I think there are risk/benefit ratios involved with all herbicide use.  In some cases, the ecological risks posed by an invasive exotic plant species are considerable, and timely one-time use of herbicide on small initial patches can save thousands of acres from becoming permanently infested and rendered essentially worthless in terms of native biodiversity. 

In other cases, some ecological restoration work can be extremely difficult without some careful limited use of herbicide.  Painting cut stumps is one example.  At the North American Prairie Conference in Wisconsin last year, a wonderful elderly woman who owned a beautiful restored oak savanna warned field trip attendees that in some circumstances, cutting invasive woodies without treating the stumps is an exercise in futility.  She said, "I tried cutting alone for awhile, but I don't have enough years left to keep cutting all those resprouts and neither do you."

The issues regarding urban lawns and rowcrops are different, of course.  For one thing, herbicide use on lawns and rowcrops is often annual and routine. 

My purpose, when I use herbicide during restoration, is to help create a situation in which I won't have to use it in the future.  One reason for the (careful) initial use of herbicide in Iowa restoration work is to help overcome the effects of decades of fire suppression.  Once that happens, prescribed burns can be used instead.

Cindy  

Cindy Hildebrand
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Ames, IA  50010

"We landed one time only to let the men geather Pappaws or the Custard apple of which this Country abounds, and the men are very fond of."  (William Clark) 
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