A 1/6/11 San Francisco Chronicle article on the cutting down of a 70-foot shoe tree in Nevada in January, 2011 referred to the tree as "well-worn artwork". Another article uses the term "monument".

Artwork may be a stretch to some, but there are apparently more than 75 such trees located throughout the United States, and more elsewhere.

Internet news items indicate that several shoe trees have been vandalized in recent years, either cut down by chainsaw, or burned. Many people view them as litter and feel that individuals should be fined for throwing shoes into the tree.

There doesn't seem to be any concrete universal understanding of how or why this phenomenon began, or what keeps it going. According to various news stories, the Nevada tree cut down in 2011 was started by a young married couple who had lost all of their money gambling and camped under the tree. During an argument, the wife threatened to walk away, and the husband threw her shoes in the tree to discourage her. Things worked out, they had a child a year or so later, and returned to add a pair of the child's shoes to the tree. And it grew from there.

Do all shoe trees have interesting stores behind them? Perhaps each pair of shoes added has its own story to tell. Maybe it's mostly litter? We will probably never know. It is nonetheless an interesting feature, and one that anybody can actively participate in "building".