Pine tree ants, liometopum luctuosum, are a native ant that loves to nest in large pine trees that have some decay in them. Houses prove to be a suitable, or additional, place to nest. These ants excavate into lumber to create room for the nest, and they will carry the sawdust and throw it out. The sawdust can accumulate in large piles, under nesting sites. These photos of the sawdust were taken by Jose Rodriquez, at a residence in Forest Meadows, Calaveras County, California, October 2017.