What is the preferred first-aid treatment for a severely bleeding forearm?

The preferred first-aid treatment for a severely bleeding forearm is to apply a tourniquet. In cases of severe bleeding, especially when a person's life is at risk due to significant blood loss, a tourniquet can help control hemorrhage by restricting blood flow to the affected area. It is essential to apply the tourniquet above the level of the bleeding, ideally a few inches above the wound, to effectively compress the blood vessels and prevent further blood loss.

While applying pressure bandages and elevating the arm may be useful in less severe cases, they might not be effective enough to manage severe hemorrhaging. Calling emergency services is also crucial but should be done in conjunction with applying a tourniquet when there is a threat of life due to excessive bleeding. Therefore, in this specific scenario of a severely bleeding forearm, using a tourniquet is the most appropriate and life-saving intervention.