I was thinking of things human put on the tree, or garbage that lies around the tree.
Katie: coast Douglas-fir: metal tag # 1444 and silhouette (May 15, 2011)
http://natureid.blogspot.com/2011/05/tree-year-project-2011-7.html
Jennifer: A clean-up project claimed my tree’s neighbors. (May 11, 2011)
http://jennifererbe.wordpress.com/2011/05/09/a-close-call-for-my-tree/
Mike B.: The tree bark grew around a small pipe. Was someone trying to make Walnut Syrup? (May 4, 2011)
http://slugyard.com/2011/05/walnut-syrup/
