Cedars: Characteristics, Habitat, Species, Uses And Diseases

The cedar (Cedrus)They are a genus of plants in the subclass Pinidae. Currently, three species are known of these conifers: Cedrus atlantica, Cedrus deodara and Cedrus libani. These gymnosperms are monoecious plants, belonging to the Pinales order, family Pinaceae, together with pines, larches, cypresses and firs. Cedrus species are known as true cedars.

The age of true cedars can reach more than 1000 years. The characteristics of the vascular tissues of the trunk make them similar to Pinus and Abies, indicating that possibly in evolution, the genus Cedrus is found between these two genera of conifers.

Cedars have a high impact on the timber industry for construction in general, as well as for the use of its resin as a raw material for paints, tar and creosote. In addition, cedar wood is very aromatic, reddish in color and incorruptible.

In addition, all species are used as ornamental plants in areas with a temperate climate. Probably the most culturally important cedar species is Cedrus libani , being venerated for millennia according to biblical accounts. It is also the symbol that appears on the flag of Lebanon.

characteristics

Tree

The gender CedrusIt groups majestic trees as much for their size as for the length and vigor of their branches, and they also have a large crown that makes them very decorative. The top of the cup can be erect or bent.

The diameter of these trees can be more than 450 cm and the height of these trees can exceed 45 meters. It is difficult to know for sure which of the three species ofCedrus It is higher, since the figures of the largest recorded specimens are similar: 43 meters for the C. libani, 45.6 meters for the C. atlantica and 45 meters for him C. deodara.

Stem

The stem, as in the rest of the conifers, is formed by a woody trunk of intermediate thickness and of great height. This trunk is covered by a reddish and cracked bark, although when the trees are young, the bark is smooth and gray.

From the stem, usually from a node, the branches are born. The plant takes the appearance of a cone, because the lower branches are longer than the upper ones (monopodial branching).

As for the branches, they are long and on these grow other short ones in which the needles or acicular leaves are grouped as a kind of tufts of needles.

Leaves

The leaves, as already mentioned, are needles that arise from the branches and can appear paired and grouped in fascicles. The leaves of the long terminal shoots are spirally arranged.

It is a species of evergreen or evergreen conifer. That is, as the senescent leaves fall, new leaves emerge. The leaves are normally covered by a waxy coating.

Root

The root, like the stem, increases in thickness since it has a cambium; In addition, these trees contain numerous channels of resin, which protects the plant from low temperatures.

flowers

They are arranged in terminal inflorescences on short shoots, and appear in late July and August. These inflorescences do well during late September and early October.

The male flowers are arranged in erect catkins about 5 cm long, while the pollen grains are non-winged and golden yellow.

Cones

Cedar pineapples don’t ripen until the second year. They have droopy scales and do not present bracts at maturity. Pollination is through the wind.

The female flowers (cones) are between 1 and 1.5 cm long, are reddish, ovate, composed of numerous scales and surrounded by needles at the base. 

For its part, the seed is large, triangular, light brown, resinous and with a large wing. It has 8 to 10 cotyledons.

Taxonomy

Cedars are part of gymnosperm plants and are located within the commonly called conifers, as well as, they are found in the group of the Pinaceae family.

Currently three species of cedar are recognized, namely: Cedrus atlantica, Cedrus deodara and Cedrus libani.

The taxonomic classification is as follows:

Kingdom: Plantae

Subkingdom: Viridiplantae

Underkingdom: Streptophyta

Superphylum: Embryophyta

Phylum: Tracheophyta

Class: Spermatopsida

Subclass: Pinidae

Order: Pinales

Family: Pinaceae

Subfamily: Abietoideae

Gender: Cedrus Trew (1757).

Habitat and distribution

Cedar species are distributed in the world in places where there are climatic conditions of elevation considered above sea level, relatively low temperatures and coniferous forests . Examples of these places are eastern Asia (from Afghanistan to Nepal), in the Himalayas and throughout the southeastern region of the Mediterranean.

Other necessary conditions for cedars to thrive is to grow in conditions of high light, since it has been observed that they develop better in places where they are exposed directly to the sun .

For their part, cedar species can adapt to soils with acidic, neutral, even alkaline or very alkaline pH. In addition, the soil may have a sandy, loamy or clay texture. According to the texture of the soil, it is necessary to try to maintain the conditions of constant humidity.

Likewise, cedars can withstand drought, but they cannot tolerate waterlogging, so good drainage is essential for their development.

Other important data about climatic conditions is that the genus Cedrus  supports strong winds and does not tolerate pollution.

Species

Cedrus libani A. Rich (Cedar of Lebanon)

It is a species of tree with a height of up to 40 meters, whose morphology is dense and irregular crown, with whorled branches of short leaves and in a horizontal position. The leaves can also be slightly curved or straight, mucronated and grouped in fascicles of 30 to 40 pairs. 

It takes place in Mount Lebanon and other places on the Asian continent such as Syria and Turkey. This species is so important to the culture and history of Lebanon that it appears as a national symbol on its flag.

This species has solitary, erect, cylindrical catkins with an attenuated apex. For their part, the strobili (pineapples) are equally solitary, erect and oval.

In ancient Egypt, this cedar was used to obtain a white resin known as cedar, which was used to embalm corpses.

Cedrus deodara (Lamb.) G. Don (Himalayan cedar)

It is commonly known as Himalayan cedar, Indian cedar, or weeping cedar. It also has some synonyms likeAbies deodara, Cedrus indica, Cedrus libani var. deodara, Cedrus libani subsp. deodara, Larix deodara, and Pinus deodara. It is distributed throughout the entire Himalayan range.

It is a tall tree with a pyramidal crown, which has whorled branches with pendulous leaves. These form groups of 30 needles and are arranged in fascicles.

This species of cedar requires a large space for its development, therefore, it is not suitable to be planted in small gardens, but must be planted alone or in groups of cedars.

Male catkins are solitary and upright, oblong-cylindrical and sharp. On the other hand, the strobili are solitary or paired, oval in shape and very obtuse. This cedar grows in the Himalayas and Tibet. Its wood is also very useful, being the most ornamental cedar.

Cedrus atlantica (Endl.) Manetti ex Carriere

This species is known in Spanish by the common name of Atlas cedar or silver cedar. Also, it has several synonyms likeAtlantic abies, African Cedrus, Cedrus libani subsp. atlantic, Cedrus libani var. atlantic, Cedrus libanitica subsp. atlantic, Pinus atlantica. The Atlas cedar is found in northwest Africa, such as Algeria or Morocco.

It is a tree that measures between 20 and 40 meters, slow-growing and cone-shaped when young and umbrella-shaped when it reaches maturity. It is a cedar with ornamental purposes due to its blue needles.

The silver cedar has an average longevity of between 200 and 400 years, although there are records of some that have reached the millennium. It is a tree that adapts well to drought and withstands temperatures down to -25 ° C. In plantations, its planting frame is 12 x 20 m. 

Applications

Cedar is a genus of trees of great importance in the wood production industry, being used for the construction of furniture, ships, etc. Thanks to the exceptional qualities they present and because they give off a resin that covers their fabrics, they make this wood a material that is not damaged (unalterable).

Another important use of your wood is its use as charcoal and paper pulp. In addition, from the resin that gives off from its trunk, the essence of turpentine or turpentine is extracted, which is used in the production of paints, tar and creosote.

From an environmental point of view, cedars can be used as ornamental trees in parks and gardens. The cedars beautify the landscape thanks to their elegant bearing and because they are always green. 

Likewise, cedars can be used in very poor soils and serve to protect the soil from erosion; Also, the forests that form these conifers are regulated by rainfall.

Diseases

Root suffocation 

Waterlogging is the leading cause of cedar death in landscaping. This occurs due to the excessive irrigation that is applied to it. Therefore, cedars must be watered with the necessary amount of water so that their roots do not rot. 

Likewise, when a cedar is transplanted it is recommended that it be carried out in a large planting hole to promote drainage. On the other hand, when they are planted in gardens, puddles should be avoided.

Fungi of the genus Phytophtora

Fungi of this genus are responsible for most of the mortality in conifers.

These fungi, when they come into contact with the roots, invade the interior of the tissues through a wound or injury caused by insects. 

Externally, while the fungus is infecting the root, a yellowing of the branches that are connected to that xylem tissue is observed, while the fungus continues to invade the entire root system. This disease is also favored by excess humidity.

The treatment of this infection is carried out with a preventive fungicide whose active ingredient is known as Fosetyl-aluminum. The degree of recovery depends on the level of infection the cedar reached before being treated.

Bold

This disease is caused by a fungus that is observed in the needles of the branches with a black appearance. The damage produced is more aesthetic than physiological. The bold is a disease that manifests itself due to the presence of pests such as aphids or mealybugs, which secrete a sweet liquid where the bold thrives.

For the treatment of the bold, soapy water should be applied under pressure, or wait for the rainwater to wash it off and eliminate it naturally.

On the other hand, it is recommended to inspect the tree every 15 days to identify the insect that produces the sugary substance and treat it with a systemic insecticide.

Other diseases

Among other conditions that can attack cedars are the canker of the branches, produced by Cytospora cedri, for which the diseased branches must be pruned and disinfectant applied to the tool used to avoid spreading the disease to other trees.

Pests

In addition to the diseases found in cedars, you can also observe certain insects that attack these trees, such as the aforementioned aphids and mealybugs. Of them, the species are recognizedCinara cedri and Cedrobium laportei.

Likewise, the pine processionary (Thaumetopoea pityocampa), causes moderate defoliation in the branches of cedars.

References

  1. The Gymnosperm Database. 2019.Cedrus. Taken from: conifers.org
  2. Fuster, PE 1944. Botany Course. Editorial Kapelusz, SA Buenos Aires, Argentina. Pages 237-239.
  3.  González, R., Luisier, A., Quer, Pío. 1971. Natural history, life of animals, plants and the Earth. 7th ed. Gallach Institute. Mallorca, Barcelona. Page 165-167.
  4. Creation, Natural History. 1876. Montaner and Simon, Editores. Barcelona, ​​Spain. Page 69. Taken from: books.google.co.ve
  5. Catalog of Life: 2019 Annual Checklist. Species details:Cedrus atlantica (Endl.) Manetti ex Carriere., Cedrus deodara (Lamb.) G. Don., Cedrus libaniA. Rich. Taken from: catalogueoflife.org 
  6. The Taxonomicon. (2004-2019). Taxon: GenusCedrusTrew (1757), nom. cons. Taken from: taxonomicon.taxonomy.nl
  7. Pérez, M. 2012. Cedrus deodara. Taken from: botanicayjardines.com
  8. Infojardín. 2019. Cedar: species of cedars. Taken from: articulos.infojardin.com

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