QUERCUS ROTUNDIFOLIA: CHARACTERISTICS, HABITAT, DISTRIBUTION, USES - BIOLOGY - 2024

Quercus rotundifolia is a species of evergreen and monoecious tree belonging to the Fagaceae family. Known as holm oak, holm oak, chaparra, continental oak, broad-leaved oak or sweet oak, it is a forest species native to the Mediterranean region.

It is a tree 8-15 m tall, with a fissured ashen bark trunk, with alternate, oblong-lanceolate and slightly pubescent leaves. Its male inflorescences are hanging catkins and the female ones are only inside an acrid involucre. The fruit is an achene partially covered by a dome.

Quercus rotundifolia. Source: Kevin T.

The holm oak is a plant that develops in full sun exposure and tolerates hot environments, supporting large variations in temperature. It grows on dry soils, but is susceptible to waterlogging. It also adapts to basic and low nitrogen soils.

In general, rot-resistant, hard wood is used to make parts with high physical labor such as plows, parquets and agricultural tools. In addition, it is an excellent raw material for obtaining high caloric charcoal.

Acorns are used as an animal feed supplement and are consumed by man as nuts or flour for pastry. The bark has astringent properties, being used for the treatment of hemorrhoids, chronic diarrhea and to cure internal bleeding.

General characteristics

Stem

The 8-12 m tall tree, up to 15 m when adult, has a dense, wide and rounded crown. The bark is profusely cracked, being grayish in color. The young branches are horizontally erect and slightly tomentose.

Leaves

The simple leaves are rounded or a little elongated, leathery, dark green on the upper side and grayish on the underside due to their abundant hairs. The margins are whole, wavy or slightly toothed, with a short petiole 3-10 mm long.

The branches and buds have abundant hairs, the juvenile leaves are generally barbed-toothed. They differ from the Quercus ilex holm oak by the presence of rounded leaves, with less than 8 veins and a smaller petiole (6 mm).

Male inflorescences of Quercus rotundifolia. Source: Luis nunes alberto

Inflorescences

The male inflorescences are hanging yellowish catkins with tiny flowers formed by a solitary whorl of 3-7 pieces and various stamens. The solitary or paired female flowers are arranged on a tomentose pedicel and a six-lobed perianth that matures at two years.

Fruit

The fruit is a sweet-tasting acorn with a short peduncle, which blooms from April-May and bears fruit from October-November. The dome that surrounds half of the acorns comes from the bracts that surround the flowers, being variable in size and shape.

Taxonomy

- Kingdom: Plantae.

- Division: Magnoliophyta.

- Class: Magnolipside.

- Order: Fagales.

- Family: Fagaceae.

- Genus: Quercus.

- Species: Quercus rotundifolia.

Quercus rotundifolia acorns. Source: Tony Hisgett from Birmingham, UK

Habitat and distribution

Quercus rotundifolia grows on calcareous or siliceous, porous and well-drained soils, even on saline or gypsum soils. Susceptible to flooding, it is very resistant to droughts, high temperatures and occasional frosts.

It inhabits Mediterranean sclerophyllous forests and scrubs, compact or pastures, in mixed associations and different substrates. It is located from sea level to 2,000 meters above sea level, in loose and deep soils.

This species is native to the western Mediterranean, distributed throughout northern Morocco, the entire Iberian Peninsula and southern France. In fact, it is located on the meso and supra-Mediterranean bioclimatic floors, occasionally thermomediterranean, as well as dry or sub-humid ombrotypes with a semi-arid predominance.

In Spain it is located in a specific way in Galicia, through the Cantabrian coast and the mountains of Cartagena. In Moratalla in the Murcia region, the Rincón de los Huertos and the Sierra de Taibilla y Seca, as well as the Sierra de Mojantes and La Zarza in Caravaca.

Quercus rotundifolia leaves. Source: Krzysztof Ziarnek, Kenraiz

Applications

Food

Quercus rotundifolia acorns have a particular sweet or sour taste due to the presence of tannins, fats and starches. Since ancient times, seeds from plants with sweet acorns have been selected to the detriment of bitter acorns.

Acorns from the Pedroches region in the province of Córdoba are famous for their size and aromatic flavor. These are used as food for human consumption, sweets or pastries, as well as a nutritional supplement for livestock.

Tannery

In the holm oak, the presence of Istrian galls is common, formed by the deposition of eggs of the hymenopteran Cynips tinctoria var. Nostra. These galls are rounded tuberculous malformations that accumulate various tannins, such as gallic acid and tannic acid.

Indeed, these small pale-yellow, reddish-yellow and dark galls are used in the tanning industry. On the other hand, the bark rich in gallic, ellagic and cornicitanic acids is used by the Cordovan tanning industry.

Wood

The dense, heavy, hard and compact wood, as well as the white or rosy outer sapwood and the reddish inner heartwood are of great timber importance. It is used in the manufacture of tools, parquet floors and loom shuttles, due to its great resistance to humidity.

Likewise, the wood used as firewood provides a high calorific charcoal, widely used for charcoal. This process consists of placing several logs under fire and covering them with branches of esparto grass and earth, thus obtaining a product of higher caloric quality.

Holm oak forest. Source: David Perez

Forage

In the region of Extremadura (Spain) and certain regions of Portugal, holm oak acorns are used as a food substitute for pigs. Acorn-fed Iberian ham obtained from pigs whose diet is exclusively with acorns of the Quercus genus is famous worldwide.

Medicinal

The bark and flowers of the holm oak are used as an effective astringent to relieve chronic diarrhea and prevent dysentery. In addition, it is used to stop bleeding from the nose, stomach and intestines, urinary tract and lungs.

Topically compresses are applied to reduce inflammation of hemorrhoids, ulcers, fistulas and stretch marks in the area of ​​the nipples. On the other hand, the infusions have diuretic properties and it is an effective antioxidant.

Melliferous

Acorns produce a nectar or sugary secretion that honey insects collect to make honey. From the holm oak a particular dark-colored honey is obtained, called honeydew or forest honey, product of the bite of certain aphids.

References

1. Do Amaral Franco, J. (1990). Quercus L. Flora ibérica, 2, 15-26.
2. López Espinosa, JA (2018) Carrasca, Chaparra, Encina Manchega. Quercus rotundifolia. Flora. Region of Murcia Digital. Recovered at: regmurcia.com
3. Quercus rotundifolia Lam. (Fagaceae) (2018) Herbarium. Recovered in: Plantasyhongos.es
4. Quercus rotundifolia (2018) Potential Vegetation Map of Navarra 1: 25,000. Department of Rural Development, Environment and Local Administration, Government of Navarra. Recovered at: cfnavarra.es
5. Quercus rotundifolia (2018) Montes de Málaga. Recovered at: montesdemalaga.org
6. Rodá, F., Vayreda, J., & Ninyerola, M. (2009). Holm oaks of Quercus ilex and Quercus rotundifolia. Ministry of the Environment, and Rural and Marine Affairs. General Technical Secretariat. Publications Center.