Basic level

The depth of the bark can be estimated by cutting through the bark to the wood or observing the bark of at least five recently felled trees.

Advanced level

Bark thickness can also be measured with a specifically designed bark gauge to an accuracy of one millimetre. It relies heavily on feel; so to minimise error the following guidelines are suggested:

• If the tree has rough or fissured bark, take measurements on the ridges of the bark.
• Take three to four measurements around the stem and average, as bark thickness may vary from one side of the tree to the other.
• Feel the change in pressure while pushing the chisel into the bark. Avoid pushing too hard or it might go into the wood.