I have built all of my shelters completely from trees that were already dead and I break them down before I break camp.  When I do need something from a live plant for something other than a shelter (food/fiber/seeds/liquid extract/etc) I take it from the plant in a way that will not kill the plant and/or in an area where that plant is quite abundant.  When I leave a campsite, the only thing I leave behind are foot prints and my human scent.... sometimes not even footprints.  <img src="/images/graemlins/cool.gif" alt="" />   
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Learn to improvise everything.