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Diameter Tape

A diameter tape (D-tape) is used by foresters to measure the diameter of a tree. Since trees are swelled at the base, measurements are made 4.5 feet above the ground in order to give an average diameter estimate. The D-tape is wrapped around a tree and is specially designed to convert the tree circumferance to tree diameter.
 

Diameter will be measured with the cloth rulers that you have made. You will need to convert each measurement after you record it, because the cloth rulers are actually measuring tree circumfrence. This is a very simple equation, just divide circumference by 3.14. (TRY THIS - use the equation for circumference and solve for diameter)    Wrap the cloth ruler around the tree stem...

and record how many inches around it is.