So far this year, U.S. imports of hardwood plywood are up more than 58 percent in volume and more than 33 percent in value, according to the Decorative Hardwood Association.

Vietnam and Indonesia are the largest sources. The U.S. imported nearly 300 million square feet from Vietnam from January through May, a staggering increase of 191%. Imports from Indonesia have already reached more than 279 million square feet, a leap of almost 50%.