Fine print: Only one guess per person, extra guesses will be discarded. Use any method you like to guess the age; however you may not perform any intrusive tests on the tree. In the link below, enter the year you think the tree was planted. In the case of a tie, winning entries will be drawn from a hat. If you view the enhanced data on the Guthrie Park arboretum, please note that the tree’s estimated age is simply that – an estimate using very broad parameters.