Bark Restrictions

WPM must be made from debarked wood. There are two allowable limits to the amount of bark present. Separate pieces of bark may be present if the following conditions are met:

a) Less than 3 cm (1 3/16 inches) in width, regardless of length; or

b) When greater than 3 cm in width, the total surface area must be less than 50 centimeters squared
(Approximately the size of a credit card).

Bark encased knots are exempt; however, should a bark pocket be visible and exceed 50 centimeters squared, it would be deemed an excessive amount of bark outside of the allowable limits. Interior bark is treated the same as exterior bark for measurable limits.

Bark is considered the “outer layer of a woody trunk, branch or root outside the cambium layer”. Pieces of bark covering several faces of a wood component must be measured widthwise from edge to edge of each patch. Excessive bark can be scraped or stripped from the wood components. Bark may be removed after the heat treatment process.