Arbutus menziesii

American strawberry tree (Arbutus menziesii)

The American strawberry tree (Arbutus menziesii ) is a plant of the genus of strawberry trees and one of the few deciduous trees of the American Northwest. Characteristic are the bright red-brown, peeling bark and leathery, glossy green leaves that turn purple in early summer. An age between 200 and 250 years been proven several times, especially strong trees is estimated as twice as old one.

  • 3.1 pollination
  • 3.2 Community
  • 3.3 mycorrhizal symbiosis
  • 6.1 Notes and references


Vegetative characteristics

It is an evergreen tree reaching a height of 7 to 40 meters and trunk diameter of 15 to 150 centimeters ( BHD), but under unfavorable conditions remains Shrubby. The trunk usually does not just grow, circular stem cross sections are rare. Often the base of the trunk arise numerous shoots. Young trees have uniformly shaped, oval crowns, indicative of the kind, however, are irregularly shaped, wide overhanging canopy of old trees.


One characteristic of the species is the formation of a heart root system, older trees have rhizomes of up to 1.5 meters in diameter. The lateral roots are strong and broad strongly vertically and horizontally. Like other forms of American arbutus arbutus ectomycorrhizae with characterizing Hartig'schen network.

Bark and wood

The bark is smooth at the beginning and deep red and begins in the autumn of the first year to replace in thin layers. The underlying cortical layer is initially pale green and turns later dark brown, but does not dissolve but forms from approximately square shed. The wood is hard and heavy with light brown to reddish core and a narrow, light-colored sapwood. The density is about 0.8 g/cm3.

Buds, shoots and leaves

The light brown winter buds are about 8 mm long, light brown and show numerous ovoid, slightly ciliated bud scales, with some having up to 37 mm can be significantly longer. The young shoots are bare and covered by a smooth, orange rind, the scaly peel off later. The leaves are leathery, oblong- ovate and mostly entire margins. Leaves on vigorous shoots or Stock rashes can also be sawed. The top is shiny dark green, the lower pale green. Full-grown leaves are 7.5 to 12.5 inches long and 3-7 inches wide. They have a strong, pale green midrib, the leaf blade is slightly heart-shaped, wedge-shaped or rounded at the base, the Spreitenspitze is rounded or pointed. The petiole is deepened from 12 to 25 millimeters long and rinnig. Young leaves are bright green, the lower leaf surface often dyed pink. The leaves stay until the early summer of the second year on the tree, color then orange to bright red and fall off in June and July.

Flowers and Fruit

The American arbutus blooms depending on the environmental conditions from mid March to mid-May. He is 12.5 inches long and about the same width, spike-like, hairy inflorescences of small, white, hermaphroditic flowers. The single flower is 8 millimeters long and short-stalked. It springs from the axil of a ciliated supporting sheet. The small cup is deep pentadentate that fünflappige corolla is fused bell-shaped. The ovary is glabrous, the scar is five-lobed, the ten free stamens shorter than the petals. The fruits ripen between mid-September and mid-October to December and can remain on the tree. They are round or pear-shaped berries with diameter of 8 to 12 mm. Ripe berries are pink to orange-red. The thin exocarp is rich glandular and warty. They contain 2-37 with means 20 dark brown seeds in five fruit trays. Per tree berries are up to 100,000 formed 5000 dried fruit weigh about 1 kg, the thousand grain weight of the seed is between 1.5 and 2.5 grams. The American strawberry tree bears about three to five years for the first time fruits, years with little or no fruit be repeated every ten years. The fruits are dispersed by birds, rodents and mule deer, especially important for dissemination are wild pigeons. The seeds germinate epigeal.

Distribution and habitat requirements

The natural range extends approximately 1900 km along the Pacific coast of the United States and southern Canada from 32 to 50 ° north latitude. The northern boundary runs through Vancouver Iceland and the adjacent mainland, the southern border near San Diego in California. Eastward penetrates the style to the western slopes of the Sierra Nevada and the heights 800-1300 meters. The upper limit in the Klamath Mountains it reaches 1435 meters above sea level.

The distribution of the American strawberry tree is characterized by a mild, cloudy coastal climate with average January temperatures between 2 and 8 ° C and average July temperatures between 10 and 20 ° C. In the area of ​​distribution appear to temperatures between about -20 ° C and 45 ° C, through rigorous frosts the species is harmed. The annual rainfall varies between 800 and 3000 mm, about three -quarters of them fall from October to March mostly as rain. The species is resistant to drought. They mostly populated weakly acidic soils of different origin, as volcanic tuffs, sedimentary rocks and diluvial sand. Be colonized loams, clays, coarse and gravelly sands and shallow soils.



Pollination is by bees. Hummingbirds also take on the flowers to food and could also contribute to pollination.


The type usually occurs in coastal forests individually or in groups, pure stands are rare. In the north, it comes together with the Douglas Fir ( Pseudotsuga menziesii), western hemlock American ( Tsuga heterophylla ), the red alder ( Alnus rubra), the Oregon maple ( Acer macrophyllum ), and the California Black Oak ( Quercus kelloggii ). To the south it thrives along with Douglas fir, the ponderosa pine (Pinus ponderosa), sugar pine ( Pinus lambertiana ), Pinus attenuata, the California Black Oak ( Quercus kelloggii ) Lithocarpus densiflorus and.

Mycorrhizal symbiosis

The American strawberry tree is a mycorrhizal symbiosis with a large number of fungal species. Under laboratory conditions, with the fly agaric (Amanita muscaria ), with the Bare knuckle Ling ( Paxillus involutus), the terrible pea litter Ling ( Pisolithus arhizus ), the Hohlfußröhrling ( Suillus cavipes ) and the tube fungus Rhizopogon vinicolor. In Northern California, they found symbioses geophilum with Lyophyllum species and Cenococcum.


The genus name Arbutus comes from Latin and is mentioned among others by Varro in his work Rerum Rusticarum de Agri Cultura, by Lucretius in De Rerum Natura, Vergil's Georgics and in the Carmina of Horace. The specific epithet menziesii refers to the Scottish gardener and plant collector Archibald Menzies (1754-1842), who accompanied George Vancouver on his travels in the North American West. According to him, the Douglas Fir ( Pseudotsuga menziesii) is named.

The English name Madrone goes back to the botanist and Spanish missionary Juan Crespe, who participated in 1769 a Spanish expedition. He recognized the close relationship of the kind with the Western Mediterranean strawberry tree (Arbutus unedo ), which is called in Spanish Madroño.


The American arbutus forestry is hardly used. Long straight stems are made ​​into veneers for furniture, they are used for floorboards or panels. Krumme strains used as firewood. The wood is suitable for turning, and since it is odorless as material for containers for storing food. Previously, the wood provided a high-quality charcoal in the production of gunpowder, and rich in tannin bark was used for tanning leather. The fruits were eaten raw and cooked by California Indians.


  • Bulk, Weisgerber, Schuck, Long, vocal, Roloff: Encyclopedia of deciduous trees. Nikol, Hamburg 2006, ISBN 3-937872-39-6
  • Template: Internet resource / maintenance / access date not in ISO format Sonja L. Reeves: Arbutus menziesii. In: Fire Effects Information System. U.S. Department of Agriculture, 2007, accessed on 21 September 2008 (English ).