How Old is that Thing? Tree that is.

Increment borer

Increment borer

Wandering around in an Oregon forest can be magical – leaving your eyes in amazement of the old growth majestic trees that fill our landscape. Maybe the question pops in your head – “How old is that tree?”  Well, believe it or not there is a non-invasive way to figure it out. No stumps, saws, drills, or fancy increment borers needed to calculate the age of a tree. Here’s the tell-all on how to do it.

How Old is That Tree Answer

The International Society of Arboriculture has a good method for figuring out how old is that tree question. To tell the age of tree.

  1. Determine the type of tree. Use a guide to figure out the species.
  2. Take a measurement of the diameter at the Diameter Breast Height or 4½ feet above stump level on the uphill side. HINT: You can measure the circumference and determine the diameter. Diameter = Circumference divided by pi (3.14)
  3. Calculate the age of the tree by multiplying the tree’s diameter by its growth factor using the species list below. Diameter X Growth Factor = Approximate Tree Age

Red Maple Species – 4.5

Silver Maple Species – 3.0

Sugar Maple Species – 5.0Big_Tree

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

A Note About Urban Trees

The formula above works really well to estimate the age of trees in the forest. Because trees in a landscape or park are often pampered, protected and sometimes older than forest grown trees, it is harder to accurately estimate the age of these trees. If you want to know how old that tree is in an urban area, find a certified arborist to help you out. They will have years of experience and can better help you determine the age and any subsequent challenges a certain tree might face. ArborPro Tree Experts are the leading certified arborists in Portland and can quickly help you determine how old that tree is. Give us a call for any of your tree service needs in Portland or the surrounding areas.

Tree photo by Culturebeat (Own work) [CC BY-SA 3.0], via Wikimedia Commons

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