The optimal boil time for root carving in the United States is typically around 30 to 45 minutes. This duration allows for the wood to absorb the necessary moisture and heat to achieve the desired level of softness and pliability for carving. The precise boil time can vary depending on the type of wood, its thickness, and the specific carving technique being employed.

The reason for this boil time lies in the physical properties of wood. When wood is boiled, the moisture content increases, causing the fibers to expand and become more pliable. This makes it easier to carve and shape the wood without splitting or cracking. According to a study by the Forest Products Laboratory, the moisture content of wood should reach between 20% and 30% for optimal carving. Boiling the wood for 30 to 45 minutes ensures that the moisture content is sufficient for carving while still maintaining the structural integrity of the wood. Additionally, a longer boil time can lead to over-saturation, which may make the wood too soft and prone to damage during the carving process.