Trees of Big Sur and the Santa Lucia Mountains of Central California

White Alder Alnus rhombifolia

A member of the Birch Family the White Alder is a deciduous medium sized tree 30-80 ft. tall. It is found in riparian habitats directly along rivers, creeks and year-round water. It is often growing in association with Willow, Sycamore, Black Cottonwood, Redwoods, and Big-leaf Maples. The female catkins look like small conifer cones. In the Santa Lucias it occurs from sea level to near 5,000 feet.

alder leaves
White Alders grow next to year-round water.

alder along the big sur riverAlders along the Big Sur River with gray to 'whitish' bark.

Alder cones green
Still green Alder "cones" in the Fall.

alder leaf and female catkinWhite Alder leaf and female or pistillate (cone-like) catkins.

White Alder male catkins
White Alder male (staminate) catkins vary in length from 1-1/2—4 inches long.

White Alder heavy with catkins
White Alder catkins in mid-winter before the leaves have appeared.

White Alder bark
The bark of the White Alder varies greatly with age. From smooth whitish-gray bark to vertical fissures often cover with lichen and moss.

White Alder Mature bark
Mature White Alder bark.

Note: White Alder is closely related to Red Alder and the two species are difficult to differentiate in the field when growing together. Characteristics of the leaf can be used to distinguish these alders, but is difficult to separate the species in winter months in the areas where they overlap.

In the Santa Lucias, White Alder are most common. If you are over 500 feet in elevation assume it is a White Alder. In mixed growth areas near the coast and below 500 feet refer to leaf characteristics. See Red Alder.

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