Most are.
BTW, it sounds more like you are describing animal rights activists than environmentalists. So the correct term would therefore be "bunny huggers" instead of "tree huggers".
Here are some tips on how to tell the difference.
[ul][*]Ifthey arechaining themselves to trees and standing in front dozers (whose operators obviously have much more self-control than I), they are tree huggers.[*]If they eat only vegetables, they are bunny huggers.[*]Wearing clothes that did not come from animals--bunny huggers.[*]Riding a bicycle--tree huggers.[*]Swerving to miss roadkill--bunny huggers.[*]Smoking weed and fighting corporations--just your regular run-of-the-mill hippie.[/ul]