The tolerance in practice
A thin strip of bark along the edge of a board, under 3 cm wide, is acceptable however long it is. A wider patch is acceptable only if that single piece covers less than 50 square centimetres. Large patches or bark across a whole face are not.
Order of operations
For methyl bromide and sulphuryl fluoride fumigation, bark must come off before treatment because it can stop the gas working. For heat treatment, bark can be removed before or after. Where a treatment has a size limit, any bark counts toward the measurement.
Why it matters at the border
Bark can harbour insects even when the wood beneath is treated. Inspectors look for it, and excess bark can be a reason to treat a shipment's wood packaging as non-compliant.
On a euro pallet
Stringer boards on EPAL pallets must have no wane, and wane is often where bark hides. A bark edge on an EPAL stringer suggests a repair or a component that is not to specification.