What is the unit of measurement called that is used to quantify lumber?

The unit of measurement used to quantify lumber is called 'board feet.' This term is specifically designed to measure the volume of lumber and is defined as a piece of wood that is one foot long, one foot wide, and one inch thick. Board feet allows for a standard way to calculate the amount of wood in a finished product or raw lumber, which is essential in the lumber industry for pricing, inventory, and production purposes.

Square feet measures area, which is not appropriate for volumetric calculations necessary for lumber. Gallons are a measure of liquid volume and do not apply to solid materials like wood. Hectares are a unit of area used primarily for land measurement and agricultural purposes, which again does not fit the context of quantifying lumber. Thus, the correct answer, board feet, specifically refers to the volume of lumber in a standardized manner suitable for various applications in woodworking and construction.