In the UK there is an old tradition if hammering coins into gnarled old trees, as an offering, the idea being that you will get a wish if the deity or sprite or spirit accepts your offering. There is a link below. Write a story that features one such tree as a secondary or tertiary character, and uses but does not begin with the phrase "once upon a time."
http://www.dailymail.co.uk/news/article-2036581/Mystery-wishing-trees-studded-coins-illness-away-sick.html
