''Quercus alnifolia'', commonly known as the golden oak, is an evergreen oak species of Cyprus. Its common English name refers to the golden coloured lower surface of its leaves. ''Quercus alnifolia'' belongs to the endemic flora of the island and it is confined to the igneous geological complex of the Troodos Mountains. In February 2006, the parliament of Cyprus selected the golden oak to be the country's national tree.

Description

The golden oak is a much branched evergreen shrub or small tree up to high. Due to its short stature (in relation to other oaks) it is sometimes referred to as the ''dwarf oak''. Its

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are simple, obovate to suborbicular, long, 1–7 cm wide, glabrous and shining dark green above and densely golden or brownish tomentose below, with serrate margins and raised nervation. The petioles are strong, long and pilose. The flowers are unisexual; the male catkins are greenish-yellow forming spreading or pendulous clusters at the tips of the branches; the female flowers are axillary, solitary or in groups of 2–3. The acorns are narrowly obovate or subcylindrical, usually tapering towards the base, 2–2.5 cm long and 0.8–1.2 cm wide, with a woody endocarp and cupule with strongly recurved scales.

Taxonomy

''Quercus alnifolia'' belongs to section ''Cerris'', as with much of the mediterranean evergreen oak species. Occasional hybridization with palestine oak (''Quercus'' ''calliprinos'') has been described.

Distribution and habitat

''Quercus alnifolia'' is restricted to Troodos Massif, where it grows on igneous geological substrate at altitudes of . It occupies dry habitats in association with '' Pinus brutia'' or forms dense maquis in mesic habitats, characterized by deep forest soils.

Ecology

Golden oak offers soil stabilisation against erosion due to its ability to colonize stony and rocky slopes. In its distribution area, ''Q. alnifolia'' is the most important broadleaved species forming pure or mixed stands, within the conifer (''Pinus brutia'', ''

Pinus nigra ''Pinus nigra'', the Austrian pine or black pine, is a moderately variable species of pine, occurring across Southern Europe from the Iberian Peninsula to the eastern Mediterranean, on the Anatolian peninsula of Turkey, Corsica and Cyprus, as wel ...

'') dominated forests of Cyprus. Thick stands of ''Q. alnifolia'' in mesic habitats, considerably modify the humidity conditions of the site and form forest soils with "mull"

humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...

favouring the existence of sciophilous herbal species. Like other members of the oak genus, ''Q. alnifolia'' forms mutually beneficial,

ectomycorrhiza An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; pl. ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobi ...

l associations with various fungi. A preliminary study in 2011, reported over 80 mycorrhizal fungi to be associated with the golden oak; the total number, however, is estimated to be much higher.

Conservation

Golden oak is protected by the forest law of Cyprus, while the habitat type "Scrub and low forest vegetation of ''Quercus alnifolia'' (9390)" is a priority habitat of Europe (directive 92/43/EEC). Large forest expanses of the species have been proposed for inclusion in the

Natura 2000 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectively ...

ecological network of the European Union.

References

{{Taxonbar, from=Q1193791 alnifolia Cyprus Mediterranean forests Endemic flora of Cyprus Plants described in 1842 Trees of Mediterranean climate