white alder (Trees & Shrubs of the Sunol Region

white alder

Alnus rhombifolia

Summary ⁷

Alnus rhombifolia, the white alder, is an alder tree native to western North America, from British Columbia and Washington east to western Montana, southeast to the Sierra Nevada, and south through the Peninsular Ranges and Colorado Desert oases in Southern California. It occurs in riparian zone habitats at an altitudes range of 100–2,400 metres (330–7,900 ft). While not reported in northern Baja California, it has been predicted on the basis of its climatic adaptation to occur there

Distribution ⁸

White alder is distributed from the Pacific coast of Baja California,
north in the coastal valleys to just north of San Francisco Bay, in the
interior foothills of the Coast Ranges and low to mid elevation slopes
of the Sierra Nevada. It is found farther north along the lower eastern
slopes of the Cascades in Oregon and Washington and in the dry interior
valleys of Oregon, extending into southern British Columbia. It extends
eastward along the main tributaries of the Columbia River to the lower
valleys of southeastern and south-central Washington, and northeastern
Oregon, reaching its eastern limits in Idaho along the Clearwater and
Snake Rivers [22].