Commercially American tulipwood, known domestically as yellow poplar, is one of the most prolific hardwood species from the U.S. hardwood forests and is unique to North America. Forest Inventory Analysis (FIA) data shows U.S. tulipwood makes up 7.7% of total U.S. hardwood growing stock and while 12.8 million m³ are harvested each year, more than 32 million m³ of American tulipwood grows naturally in the hardwood forests during the same period. Tulipwood has less strong grain characteristic than species such as ash and oak and exhibits a marked difference between the sapwood and heartwood. The sapwood is creamy white whereas the heartwood can vary from pale yellow or brown to green and purple in extreme cases. The wood darkens on exposure to light. Tulipwood has extraordinary overall strength properties relative to weight, making it highly suitable for structural applications, such as glue-laminated beams and cross laminated timber (CLT).