American strawberry tree
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American strawberry tree ( Arbutus menziesii ) |
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| Arbutus menziesii | ||||||||||||
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The American strawberry tree ( Arbutus menziesii ) is a species 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 the leathery, glossy green leaves, which turn purple in early summer. A maximum age between 200 and 250 years has been proven several times, particularly strong trees are estimated to be twice as old.
description
Vegetative characteristics
It is an evergreen tree that reaches a height of 7 to 40 meters and a trunk diameter of 15 to 150 centimeters ( BHD ), but remains shrub-shaped under unfavorable conditions . The trunk usually does not grow straight, circular trunk cross-sections are rare. Numerous shoots often arise from the base of the trunk . Young trees have evenly shaped, oval crowns, but the irregularly shaped, widely spreading crowns of the old trees are characteristic of the species.
root
A characteristic of the species is the development of a heart root system , older trees have rhizomes up to 1.5 meters in diameter. The side roots are strong and spread strongly vertically and horizontally. Like other strawberry trees, the American strawberry tree forms ectomycorrhizae with a characteristic Hartig network .
Bark and wood
The bark is smooth and deep red at the beginning and begins to peel off in thin layers in the autumn of the first year. The layer of bark underneath is initially pale green and later turns dark brown, but does not peel off, but rather forms almost square scales. The wood is heavy and hard with a light brown to reddish core and a narrow, light colored sapwood . The bulk density is about 0.8 g / cm 3 .
Buds, shoots and leaves
The light brown winter buds are about 8 millimeters long, light brown and show numerous egg-shaped, somewhat ciliate bud scales, some of which can be up to 37 millimeters longer. The young shoots are bare and covered by a smooth, orange-colored bark that later flakes off. The leaves are leathery, usually with entire margins and oblong-egg-shaped. Leaves on strong shoots or on stick rashes can also be sawn. The top is glossy dark green, the underside pale green. Adult leaves are three to four inches long and three to seven inches wide. They have a strong, pale green central rib, the blade is slightly heart-shaped, wedge-shaped or rounded at the base, the tip of the blade is rounded or pointed. The petiole is 12 to 25 millimeters long and deeply grooved. Young leaves are light green, the underside of the leaf often pink. The leaves stay on the tree until early summer of the second year, then turn orange to bright red and fall off in June and July.
Flowers and fruits
The American strawberry tree blooms from mid-March to mid-May, depending on the environmental conditions. It forms spike-shaped , hairy inflorescences of small, white, hermaphrodite flowers that are 12.5 centimeters long and about equally wide . The single flower is 8 millimeters long and has a short stalk. It arises from the armpit of a ciliate bract . The small calyx is deeply five-toothed, the five-lobed corolla is fused together like a bell. The ovary is bare, the stigma is five-lobed, the ten free stamens are shorter than the petals . The fruits ripen between mid-September and mid-October and can stay on the tree until December. They are round to pear-shaped berries with a diameter of 8 to 12 millimeters. Ripe berries are pink to orange-red. The thin exocarp is rich in glands and warty. They contain 2 to 37 with a mean of 20 dark brown seeds in five fruit compartments. Up to 100,000 berries are formed per tree, 5,000 dried fruits weigh around 1 kilogram, the thousand-grain mass of the seeds is between 1.5 and 2.5 grams. The American strawberry tree bears fruit for the first time after about three to five years; years with little or no fruit are repeated about every ten years. The fruits are spread by birds, rodents and mule deer , with wild pigeons being particularly important for spreading. The seeds germinate epigeously .
Chromosome number
The number of chromosomes is 2n = 26.
Distribution and location requirements
The natural range extends about 1900 kilometers along the Pacific coast of the United States and southern Canada from 32 to 50 degrees north latitude . The northern border runs through Vancouver Island and the neighboring mainland, the southern border at San Diego in California . Eastward the species penetrates to the western slopes of the Sierra Nevada up to heights of 800 to 1300 meters. It reaches its upper limit in the Klamath Mountains at 1,435 meters above sea level.
The distribution area of the American strawberry tree is characterized by a mild, cloudy coastal climate with mean January temperatures between 2 and 8 ° C and mean July temperatures between 10 and 20 ° C. Temperatures between about −20 ° C and 45 ° C occur in the distribution area, and the species is damaged by severe frosts. The annual precipitation fluctuates between about 800 and 3000 millimeters, about three quarters of it falls from October to March mostly as rain. The species is resistant to drought. It mostly inhabits weakly acidic soils of various origins, such as volcanic tuffs, sedimentary rocks and diluvial sands. Loam, clays, coarse and gravelly sands and shallow soils are settled.
ecology
pollination
Bees are responsible for pollination. Hummingbirds also feed on the flowers and could also contribute to pollination.
Community
The species usually occurs singly or in groups in forests near the coast, pure stands are rare. In the north it occurs together with the Douglas fir ( Pseudotsuga menziesii ), the West American hemlock ( Tsuga heterophylla ), the red alder ( Alnus rubra ), the Oregon maple ( Acer macrophyllum ) and the California black oak ( Quercus kelloggii ). In the south it thrives with Douglas fir, the yellow pine ( Pinus ponderosa ), the sugar pine ( Pinus lambertiana ), Pinus attenuata , the California black oak ( Quercus kelloggii ) and Lithocarpus densiflorus .
Mycorrhizal symbiosis
The American strawberry tree forms a mycorrhizal symbiosis with a large number of types of fungus. Under laboratory conditions with the fly agaric ( Amanita muscaria ), with the bald curly mushroom ( Paxillus involutus ), the common pea litter ( Pisolithus arhizus ), the hollow- footed boletus ( Suillus cavipes ) and the tube mushroom Rhizopogon vinicolor . In Northern California, symbioses with Lyophyllum species and Cenococcum geophilum were found .
etymology
The generic name Arbutus comes from Latin and is mentioned by Varro in his work Rerum Rusticarum de Agri Cultura , by Lucretius in De rerum natura , in Virgil's Georgica 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 to the Northwest of America. The Douglas fir ( Pseudotsuga menziesii ) is named after him.
The English name Madrone goes back to the botanist and Spanish missionary Juan Crespe , who took part in a Spanish expedition in 1769. He recognized the close relationship of the species with the Mediterranean western strawberry tree ( Arbutus unedo ), which is called Madroño in Spanish .
use
The American strawberry tree is hardly used for forestry. Long straight trunks are processed into veneers (madrona) for furniture, they are used for flooring or as panels . Crooked logs serve as firewood. The wood is suitable for turning, and because it is odorless, it can be used as a material for containers for storing food. The wood used to provide a high quality charcoal for making gunpowder , and the tannin- rich bark was used to tan leather. The fruits were consumed raw and cooked by California Indians.
proof
- Schütt, Weisgerber, Schuck, Lang, Stimm, Roloff: Encyclopedia of Deciduous Trees . Nikol, Hamburg 2006, ISBN 3-937872-39-6
- Sonja L. Reeves: Arbutus menziesii. In: Fire Effects Information System. US Department of Agriculture, 2007, accessed September 21, 2008 .
Individual evidence
- ↑ a b c d Schütt et al .: Encyclopedia of Deciduous Trees , p. 118
- ↑ a b c d Schütt et al .: Encyclopedia of Deciduous Trees , p. 122
- ↑ a b Schütt et al .: Encyclopedia of Deciduous Trees , p. 119
- ↑ a b c Schütt et al .: Encyclopedia of Deciduous Trees , p. 121
- ↑ a b c Schütt et al .: Encyclopedia of Deciduous Trees , p. 120
- ^ A b Sonja L. Reeves: Arbutus menziesii
- ↑ Arbutus menziesii at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ a b Schütt et al .: Encyclopedia of Deciduous Trees , p. 123.
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 73 (reprint from 1996).
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 , p. 381 (reprint from 1996).
