How Can You Tell How Old a Living Tree Is?
Each species of trees grows at a different rate. The International Society of Arboriculture ( www.isa-arbor.com ) has developed a guideline for the most common trees species to indicate the growth factor. By measuring the diameter of the living tree and using the calculations for growth developed by the ISA, you can estimate the age of a living tree without doing any damage.
A homeowner in Nashua, NH had been in her home for over three decades. A large oak tree in her front yard had been there the entire time. Curious of how to best estimate the age of the tree, this homeowner was looking for information.
Best Estimates for Growth by Tree Species
There are organizations, including the ISA, that have put together a chart of growth factors by tree species. You only need to you to know the diameter of the tree to get a rough estimate of its age. Using a tape measure, 4.5 feet above stump level you can measure the circumference of the tree. Then using the equation Diameter = Circumference / 3.14, you can find the tree’s diameter.
The most accurate way to estimate the age of a tree is by counting the trunk’s rings. With a living tree, this can be done by boring a sample from the tree trunk. However, this can damage the tree beyond repair and is not recommended.
Other Factors Can Affect Tree Growth and Age Estimations
The calculations done by the ISA are only a best estimate of tree age. There are many factors that can affect the growth rate of a tree over the years. These factors include water availability, light, soil conditions and root stress. Disease and pests can also stunt a tree’s growth.
The homeowner in Nashua, NH was able to get an estimated age for her oak tree of 78 years, and looks forward to continuing to watch the tree grow for years to come.
