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For the typical homeowner, the tree measurement process can seem complicated and daunting. However, volunteers from the Maryland Big Tree Program are happy to measure your tree at no cost to you, provided your tree is large enough to meet the minimum size standard, which is 70% of the current State champion for that species. Therefore, we will need you to measure your tree’s circumference. The circumference of a tree is a good indicator of the size of the tree. 

To measure a prospective champion, you will need some basic tools. Below, you will find the accepted methods for measuring trees. All measurements will be accepted, but they will need to be verified before champion status will be given. 

Graphic representations of the tree measurement point system can be viewed here.


First you will need a flexible tape measure or piece of string. Make sure the trunk is clear of vines and other barriers to a clean measurement. Estimate 4’ 6” from the ground up the trunk - what is called “circumference breast height” and is abbreviated as CBH. Secure the tape or string to the tree. Bring the tape/string around the trunk keeping it level to the ground (see photo to the left). Record the measurement or measure the string. When you nominate your tree using the Nomination Form, write in the circumference either in feet and inches or in total inches.


Sometimes trees have multiple trunks arising from a single root mass. In the photo to the right, you can see the tree has a greater circumference at 4’ 6” than at 3’. In these cases, the home owner should measure the circumference at the smallest circumference below 4’ 6”.  This tree’s circumference was measured at 3’ above ground, just about at the waist of the volunteer in red.


Some trees have multiple trunks that divide below 4’ 6”. In these cases, only the largest trunk can be measured for the circumference. In the photo to the left, the left hand trunk was measured at 4’ 6".


For homeowners who want to attempt to measure their entire tree (height and crown spread as well as circumference), go to:

The natural form of some smaller species is to divide into multiple leaders below 4' 6". Notice in the photo to the left, the flowering dogwood divides into multiple leaders below 4' 6". This is an example of a species whose natural form permits an exception to the policy about multiple leaders. This tree was measured at 8" above ground below the division.

There may be other exceptions to the CBH rule.

If you want to nominate a tree and are not sure if your tree is eligible, please send an email to We request a photo of the tree's form and some ID keys if possible (leaves, flowers, etc.) so we can attempt to identify the tree.

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