Oregon Ash Foliage And Samaras

Day 313: When Pacific Northwesterners hear the word "ash" used to indicate a native plant, the image which springs immediately to mind is of Sitka Mountain Ash (Sorbus sitchensis). The name is misleading. Sorbus is not an ash at all, despite the fact that its leaf arrangement resembles that of true ashes (Fraxinus). Sometimes called Rowan, Sorbus is a member of the Rosaceae family (Rose) and bears clusters of orange-red berries in the fall, much to the delight of migrating Cedar Waxwings and Grosbeaks. On the other hand, Oregon Ash is a true ash; Fraxinus in the Oleaceae is akin to olives and lilacs, and its fruit is a samara which contains a single seed. The papery wings of the samara allow it to be wind-carried to distances beyond the parent tree rather than falling to the ground directly beneath it as a nut would. When a mature ash grove forms, it can be very effective in shading out opportunistic and frequently undesirable understory plants such as Reed Canary Grass. For this reason, the Nisqually Land Trust chose it as one of the native species to be used in the restoration of Ohop Valley.