Fraxinus latifolia, the Oregon ash, is a member of the ash genus Fraxinus, native to western North America. Description Fraxinus latifolia is a medium-sized deciduous tree that can grow to heights of in height, with a trunk diameter of in its 100−150-year average life span. Oregon ash can grow considerably larger and can have well over a 200-year life span, or become stunted and very small in more dry habitats. It can develop a broad crown, almost as wide as a bigleaf maple (Acer macrophyllum) when it grows in the open, but crowns remain narrow when they are part of a denser tree stand, similar to that of red alder (Alnus rubra). The bark is distinctive with dark gray–brown, and it will eventually develop a woven pattern of deep fissures and ridges. The compound leaves are pinnate, long, with 5–9 leaflets attached in pairs to a linear stalk and an additional leaflet at the tip. Each leaflet is ovate, long and broad. The leaves are noticeably lighter green than those of associated broadleaf species, and turn bright yellow and fall off early in autumn. It is common for the leaves and bark to show signs of disease and brown rot on otherwise healthy plants. After leaves have fallen off the plant in fall and before it begins to leaf out, Oregon ash can be identified by its stout twigs and opposite branching arrangement and opposing buds. Unlike bigleaf maples, ash twigs have woolly hairs. In mid to late spring, the tree produces small flowers that are not very noticeable. It is dioecious; it requires two separate plants (male and female) to successfully pollinate and reproduce. The fruit, produced by female trees, is a cluster of samaras, long that includes wings similar to maple trees. It is shaped like a canoe, with the small seed located near one end. Distribution and habitat Fraxinus latifolia is found on the west side of the Cascade Range from southwestern British Columbia south through western Washington, western Oregon, and northwestern California; and in central California in the Sierra Nevada. The Oregon ash grows mostly in wet habitats and prefers damp, loose soils such as sloughs, swales, wet meadows, swamps, streams, and bottomlands. It grows from sea level to in elevation, up to in the south of the range in California. In central Southern California, it integrates with Fraxinus velutina (velvet ash) of southern California east