Regardless of whether you use hardwood or softwood in the production of your ISPM 15 conforming WPM, bark can be a challenge. The goal of this newsletter is to help facilities better identify it so bark can be addressed to meet conformance. Below is a description of what bark is and how to identify it on wood.
Measuring Bark & the Use of Bark Cards
The measurement of bark occurs at its widest point and includes both inner and outer bark. If it is less than 1-3/16″ it is considered conforming. Conforming bark will be narrower than the notch or green stripe on the TP bark cards (1-3/16″).
Anything wider than this is considered non-conforming unless it can fit into a 50 cm2 area. Using the bark cards, the card size or window, depending on the bark card you have, is the equivalent to 50 cm2 so the total amount of continuous bark in question needs to be less than the size of the window or credit card sized bark card. If there is a total break in bark so it is not connected to any other bark, it is considered a separate piece and measured accordingly.
Below are several examples of how bark is measured.
- What About Cambium?
Cambium is a paper thin layer of cells that is sometimes confused with inner bark (see pictures below). The cambium layer is difficult to identify because it is so thin and can deviate in color depending on the species of wood. For these reasons, it is recommended to remove all non-conforming bark to the wood rather than trying to remove it just to the cambium. If an inspector finds bark (innner and/or outer) that exceeds ISPM 15 it will be documented as a non-conformance. Generally speaking, if there is any thickness to the material being discussed in this information, consider it bark and remove it to meet ISPM 15 conformance.
Knowledge is Important
Non-conforming bark is one of the biggest issue facilities face when trying to conform to ISPM 15. Please make sure everyone understands what bark is and how to properly remove it so WPM that will receive an IPPC mark conforms to ISPM 15 regulations. With bark being such a serious issue, it is best not to take a chance with it so when in doubt remove everything questionable to the wood.