Lithocarpus Densiflorus

The Lithocarpus Densiflorus is commonly known as Tan Oak, Tanbark-oak, as well as Tanoak

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Growing Regions

A major component of coastal mixed evergreen forests, tanoak is distributed from the Cascade Mountains of southwestern Oregon southward through the Klamath Mountains and California Coast Ranges to Ventura County [25,34,42].  In northern California, tanoak ranges inland to the lower slopes of Mount Shasta and occurs intermittently along the west slope of the Sierra Nevada as far south as Mariposa County [31].  Sierra stands are locally abundant in Butte and Yuba Counties [13].  Recent inventories indicate that this hardwood comprises the dominant cover type over at least 861,000 acres (350,700 ha) in California [4]. Shrub tanoak (var. echinoides) occurs in chaparral communities throughout the mountains of northern California and southern Oregon, becoming particularly abundant in the vicinity of Mount Shasta [31,34,42].  Scattered populations also occur in the southern Coast Ranges and in the central Sierra Nevada [34].

     

General Information

The currently accepted scientific name of tanoak is Lithocarpus densiflorus (Hook. & Arn.) Rehd. [56]. Tanoak is the only North American representative of a large Asian genus. The genus Lithocarpus is considered a link between true oaks (Quercus) and the chinquapins and chestnuts (Castanopsis and Castanea), possessing characteristics of each [34,42]. A shrubby growth form of tanoak, commonly known as shrub tanoak, has been recognized at the varietal level as Lithocarpus densiflorus var. echinoides (R. Br.) Ambrams.[17,34,56]. Unless stated otherwise, this discussion pertains to the typical variety, L. densiflorus var. densiflorus.

Self-perpetuating stands of tanoak are indicative of climax conditions
in a number of communities within evergreen hardwood [35], mixed
evergreen [1,10,55], redwood (Sequoia sempervirens) [47,55], and mixed
conifer forests [44].

Within mixed evergreen forests in southwestern Oregon, Atzet [1]
describes climax tanoak communities associated with warm, moist sites
along the lower slopes of the Siskiyou Mountains.  Even though most
stands are currently dominated by a Douglas-fir (Pseudotsuga menziesii)
overstory, Douglas-fir is a fire-maintained, seral component within
these stands.  Climax understory dominants within the tanoak series may
include vine maple (Acer circinatum), Cascade holly grape (Berberis
nervosa), poison-oak (Toxicodendron diversilobum), salal (Gaultheria shallon),
vanilla leaf (Achlys triphylla), common prince's-pine (Chimaphila
umbellata), and twinflower (Linnaea borealis).

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