These trees were planted by a gardening company in our courtyard. We would love to match the trees' ages with neighborhood kids' ages so they can see the trees growing along with themselves over the years. The childred will be able to attach their photo to 'their' tree. Unfortunately, the gardening company was unable (or unwilling) to give me estimates on the tree ages. Who could throw in some guesses on the ages of these trees?
There are a couple of ways you can go about this.
One way is to use the formula developed by the International Society of Arborists for calculating the age of a tree from its diameter. You measure the diameter of the tree "at breast height" or about 4 feet off the ground (actually, measure its circumference and divide by 3.14). Then you find the appropriate growth factor for that tree type, and multiply it by the diameter to get the tree's age.
Tree Species | Growth Factor Red Maple Species | 4.5 Silver Maple Species | 3.0 Sugar Maple Species | 5.0 River Birch Species | 3.5 White Birch Species | 5.0 Shagbark Hickory Species | 7.5 Green Ash Species | 4.0 Black Walnut Species | 4.5 Black Cherry Species | 5.0 Red Oak Species | 4.0 White Oak Species | 5.0 Pin Oak Species | 3.0 Basswood Species | 3.0 American Elm Species | 4.0 Ironwood Species | 7.0 Cottonwood Species | 2.0 Redbud Species | 7.0 Dogwood Species | 7.0 Aspen Species | 2.0
That method is more accurate for older trees, and may not be as accurate for your young trees. Also on younger trees, it can be challenging to measure the DBH because there may be branches in the way. But, since all you really need is an estimate, this may be fine. Plus it gives you an activity to do with the children.
Another method is to read the tags on the trees to find out what nursery or tree supplier they came from. It may say on their website how old their trees of each species typically are. Or you can contact them and ask. This might require some interpretation on your part, to figure out what size of tree your gardeners planted.