 Fatwood

Fatwood, also known as "fat lighter", "lighter wood", "rich lighter", "pine knot", "lighter knot", "heart pine" or "lighter'd", is derived from the heartwood of pine trees.The stump (and tap root) that is left in the ground after a tree has fallen or has been cut is the primary source of fatwood, as the resin-impregnated heartwood becomes hard and rot-resistant over time after the death of the main tree.