The western larch has very thick bark that contains little resin and is remarkably fire-resistant. Fire actually favors the western larch because it needs full sunlight, can quickly invade open areas, and grows swiftly. However, the western larch is quite susceptible to other problems, such as parasite attack. The dwarf mistletoe Arceuthobium laricis has caused serious hardship for western larch stands in Oregon and Washington, resulting in their vulnerability to other diseases, thinning, and even death.