Calocedrus decurrens, with the common names incense cedar and California incense cedar (syn. Libocedrus decurrens Torr.), is a species of coniferous tree native to western North America. It is the most widely known species in the genus, and is often simply called incense cedar without the regional qualifier. Description Calocedrus decurrens is a large tree, typically reaching heights of and a trunk diameter up to . The largest known tree, located in Klamath National Forest, Siskiyou County, California, is tall with a circumference trunk and a spread. Specimens form a broad conic crown of spreading branches. The bark is orange-brown weathering grayish, smooth at first, becoming fissured and exfoliating in long strips on the lower trunk on old trees. Specimens can live to over 500 years old. The foliage is produced in flattened sprays with scale-like leaves long; they are arranged in opposite decussate pairs, with the successive pairs closely then distantly spaced, so forming apparent whorls of four; the facial pairs are flat, with the lateral pairs folded over their bases. The leaves are bright green on both sides of the shoots, with only inconspicuous stomata. The foliage, when crushed, gives off an aroma somewhat akin to shoe-polish. The seed cones are long, pale green to yellow, with four (rarely six) scales arranged in opposite decussate pairs; the outer pair of scales each bears two winged seeds, the inner pair(s) usually being sterile and fused together in a flat plate. The cones turn orange to yellow-brown when mature about 8 months after pollination. The pollen cones are long. Distribution The bulk of the tree's range is in the United States, from central-southwestern Oregon through most of California and the extreme west of Nevada, as well as a short distance into northwest Mexico in northern Baja California. It grows at altitudes of . Ecology At lower elevations, associated trees include oaks and ponderosa pine. Giant sequoia bears similarities to the species, but has sharp leaves. In the south–southwest U.S. some have confused bushy junipers for incense cedar. With its thick basal bark, the incense cedar is one of the most fire- and drought-tolerant plants in California. Although the tree is killed by hot, stand-replacing crown fire, it spreads rapidly after lower-intensity burns. This has given the incense cedar a competitive advantage over other species such as the bigcone Douglas-fir in recent years. Incense cedar is more shade tolerant than Douglas-fir,