Wood checking at log and lumber ends is one of the most common defect and often results in great loss of wood value. The common method to prevent wood checking is to apply a coating on log or lumber ends. However, the effectiveness of various coating products on different wood species is not clearly established, and the expected efficacy of the products to prevent checking is often not reached. This project was conducted to evaluate the effectiveness of various wood coatings against wood checking and to optimize application process on log and lumber ends, as well as components of hardwood species.
Logs, green lumber and dried components of sugar maple and yellow birch were used in this study. Five commercial coating products produced in Canada and the USA were evaluated, and two application methods were examined. The treatments were conducted on 120 fresh logs, 200 boards and 100 components per wood species in 2006 and 140 logs per species in 2007.
The results of the study showed that all coating products used in the tests were able to effectively reduce check development in logs, lumber and components. The best treatment reduced checking in lumber and components up to 100% and in logs up to 80% for a 8-week period. The effectiveness level of the products varied depending on wood species, type of wood products, treating time, application method, and storage conditions. None of the products was totally superior to others under any of the test conditions.