flushcut
TreeHouser
On the trees that I have seen it is pretty obvious which ones have  ben cabled and braced. A cheap metal detector would work I think but I do like the hi-tech idea of using the net to catalog trees. Only problem with that is each tree needs to be cataloged and if they aren't well, cutters beware.
				
			 
	 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		