Final answer:
A tree with a two foot crack requires a square defect cut to remove the damaged section and make the lumber usable, similar to other undamaged trees at a lumberyard.
Step-by-step explanation:
When Dalya and James visited the lumberyard and noticed a tree with a two foot crack, the cut that will need to be performed to make the tree usable for lumber is known as a square defect cut. This type of cut is designed to remove the cracked or defective portion of the tree so that the remaining wood can be utilized effectively, which is important when considering production in the short run for tree cutting (for lumber) using tools like a two-person crosscut saw. By making a square defect cut, the lumber extracted from the tree will match the quality of other trees that are intact without any cracks or damage.