When scientists want to calculate the age of a beech tree without harming the tree, they take a core sample of the tree and count the rings in a core sample. But unless you have the proper tools and expertise, you should not attempt to drill into the side of a beech tree to take a core sample. Instead, you can guess the age of a beech tree based on historical documents or on the size of the tree.
Visit your local courthouse and look through surveys of the property that the tree is on for references to the tree. Some surveys use specific trees as landmarks for property boundaries. And blueprints for houses or landscape architecture plans may incorporate a specimen tree. Some trees are planted specifically to serve as landmarks for property boundaries. Finding such a tree is a clue to the tree's age.
Look for photographic documentation of a tree. Photos that have the tree in the background may help you to pinpoint the tree's age.
Compare your beech tree to other beeches of the same size that have been felled. You can count the rings of a fallen beech tree of the same size, and have a rough estimate of your own tree's age.
Compare your beech tree to beech trees of the same size listed with the National Register of Big Trees. To compare your beech tree, measure the circumference of the trunk at a point 4 feet from the ground. Then measure the tree's height in feet and the spread of the tree's crown (the vertical width of the tree's branches) in feet.
Assign points to the tree by adding the tree's circumference, height and overall crown spread.
Compare your beech to a tree with the same point score that is registered with the National Register of Big Trees.