[pilleya]

Processed woods such as chipboard, mdf and plywood are ok

"Finished, manufactured, or naturally weathered products including carvings, driftwood, furniture, picture frames, and musical instruments, and plywood are allowed into the U.S., but you need to declare them so the items can be inspected by CBP."

If these are to go in a tool crate, you previously mentioned you may be better off going for metal or a combination of non-wood materials such as plastics and metals. As it will most likely safe you weight when you ship it, saving you significant amounts of money over the long term, it'll also last longer in most cases.