Quercus humboldtii
Encyclopedia
Quercus humboldtii, commonly known as the Andean Oak, Colombian Oak or Roble, is a species of oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 in the Fagaceae
Fagaceae
The family Fagaceae, or beech family, comprises about 900 species of both evergreen and deciduous trees and shrubs, which are characterized by alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of cup-like nuts. Fagaceous leaves are often...

 family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

. It is endemic to the highlands of northern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, with an altitudinal range from 1,000 to 3,200 m. It is found on all three Andean cordilleras and some lowland inter-Andean regions.

Description

Quercus humboldtii is an evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 which grows to a height of 25 m and a diameter of 1 m, with buttresses of up to 1 m. Its bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

 is reddish grey or grey and fissured, breaking into squares and flaking. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 simple, alternate and lanceolate, up to 10-20 cm long, and clustered at the ends of the branches. The flowers are small, yellow, and unisexual, with a racemic inflorescence. Male flowers are numerous, with long-styled female flowers in a cupula. The fruit is a light brown, ovoid capsule, or acorn, with a leathery pericarp, 20-25 mm in diameter and 50-70 mm long, resting on a scaly cupule. Only one fruit per cupule is developed, and the inside of the acorn shell is woolly.

The tree grows in the Andean highlands where the mean annual temperature is 16-24ºC, and the mean annual rainfall 1500-2500 mm. It can be found in moderately fertile and deep soils as well as in degraded soils, preferring shallow soils with a thick layer of humus. The acorns provide important food for wildlife; two parrots - the Rusty-faced Parrot
Rusty-faced Parrot
The Rusty-faced Parrot is a species of parrot in the Psittacidae family.It is found in Colombia, Venezuela, and Ecuador. Its natural habitats are subtropical or tropical moist montane forests and subtropical or tropical high-altitude shrubland. It is threatened by habitat loss.-References:*...

 and Fuertes's Parrot - are endemic to the threatened montane ecosystems of the Colombian Andes and are particularly dependant on the Andean oak forests as a home.
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