AILE: CHARACTERISTICS, HABITAT AND ECOLOGICAL ASPECTS - BIOLOGY

Alnus acuminata or alder. As it is commonly known, it is a tree of the Betulaceae family, which is distributed in the American continent from Mexico to Argentina. In Mexico, it is also frequently cited as aile, llite, birch, elite or palo de águila

The alder is a semi-deciduous tree that can be about 25 meters high and 45 cm in diameter. It has a superficial root system and the leaves are about 8 cm long and 5 cm wide, with an elliptical shape, serrated margin, leathery texture and free stipules.

Alnus acuminata. Frank R 1981

This arboreal species produces elongated and pendulous male flowers about 7 cm long. The female flowers are pineapple-shaped and are between 3 cm long and 1.5 cm wide.

It is a species of great ecological importance in the successions of ecosystems. It stands out for interacting symbiotically with microorganisms to fix molecular nitrogen and establish mycorrhizal associations.

The wood of this plant species, being light, is used to make wooden boxes, handicrafts, lathes and moldings.

characteristics

Tree

The alder is a deciduous tree species that can measure between 10 and 25 meters in height, and can even reach up to 30 meters. The diameter at chest height can measure between 35 cm and 1 meter. It has been observed that some individuals in plantations can exceed 42 meters in height.

The trunk is cylindrical-oval and can develop several trunks. In plantations, this tree produces thick branches from its base, while in dense forest the trunks can be free of both branches and knots by natural pruning.

For its part, the bark can look smooth or slightly rough, with some scales on old trees. Also, in the bark there are some transverse wrinkles or constrictions around the stem.

Leaves

This species has a narrow canopy with a pyramidal shape if it is found within plantations, while if it is found in successional forests it is irregular in shape.

The leaves have an ovate blade and are 6 to 15 cm long and 3 to 8 cm wide; the edge is serrated, while the upper surface and underside do not show pubescence in the mature stage of the plant.

Alnus acuminata leaves. Frank R 1981

Flower

Alnus acuminata has male catkin-like inflorescences about 5-10 cm long. They are usually grouped three by three. In turn, the female inflorescences are grouped three to four in racemes, measuring between 3 and 8 mm during flowering and possessing cones 11 to 28 mm long and 8 to 12 mm in diameter.

Inflorescence of Alnus acuminata. Frank R 1981

Fruit

The fruit of the aile is obovate or elliptical, leathery and with a winged margin. It has narrow wings 2 to 2.3 mm long and 0.2 to 1 mm wide, while the fruit body measures 1.5 to 3 mm long and 1.5 to 1.8 mm wide.

Taxonomy

Kingdom: Plantae

Phylum: Tracheophyta

Class: Equisetopsida

Subclass: Magnoliidae

Superorder: Rosanae

Order: Fagales

Family: Betulaceae

Genus: Alnus Mill.

Species: Alnus acuminata

Kunth, 1817.

Some synonyms for this species are Alnus acuminata var. genuina, and Alnus jorullensis var. acuminata.

Habitat and distribution

Alnus acuminata is distributed between an altitude of 1300 to 2800 meters above sea level. It is a species native to Mexico and the rest of Central America. It inhabits from the north of Mexico to the north of Argentina, including the Andean area of Peru and Bolivia. For its part, it has been successfully introduced in Chile, as in New Zealand.

The aile can be both a native and a cultivated species. In this sense, its cultivation is extensive from plantations from Costa Rica to Peru, along the mountain range.

Inflorescence of Alnus. Source: pixabay.com

Regarding the climatic conditions in which it thrives, the temperature ranges from 4 to 27 ° C, although it can occasionally withstand temperatures below 0 ° C. Precipitation should be between 1000 to 3000 mm per year.

It grows in silty or silty-sandy soils, deep, with good drainage, yellow-rocky, vertic and eutric cambisol. Additionally, the soil must be rich in organic matter, gravel, sand, and clay.

In relation to the ecological zones where they can be found, these can be gallery forests, tropical deciduous forest, oak forest, pine forest, sub-evergreen tropical forest, and mountain mesophilic forest. In general, they are zones that go from humid temperate to sub-humid temperate.

Ecological aspects

The alder has great importance in the successions of an ecosystem, since it is a secondary species. Therefore, it is a species of great importance in the early successional stages of pine forests and in mountain mesophilic forests, especially in eastern Mexico.

Likewise, this species can be invasive of exposed sites, because it can quickly establish itself in the gaps left by other trees and in this way it can form secondary groves that can spread over a large area.

For their part, the ailes are also known as pioneer species because they can develop successfully in disturbed sites. This can help the establishment of other plant species due to their physiological capacity to symbiosis with microorganisms and fix atmospheric nitrogen. A great solution to avoid soil erosion.

Alnus acuminata. Source: wikimedia commons

Alnus acuminata can be associated with vegetations such as Pinus spp., Quercus spp., Abies sp., Bacharis sp., Pteridium aquilinum, Prosopis sp., Acacia sp., Comus sp., Salix sp., Fraxinus sp., Tilia sp.

Biological interactions

From the biological and physiological point of view, Alnus acuminata is an arboreal species of great importance for nature due to the particular symbiosis it forms with actinomycete microorganisms of the genus Frankia sp.

This symbiosis allows the formation of a structure called a nodule, in which the biological fixation of nitrogen occurs thanks to the presence of the nitrogenase enzyme provided by the microorganism.

In these nodules, while actinomycete fixes nitrogen and makes it available to the plant, it is benefiting from the photoassimilates produced by the tree. This represents a competitive advantage in establishing species in succession and, in turn, enriches the soil with nitrogen.

Alnus acuminata plantation in Costa Rica. Pokeni

On the other hand, Alnus acuminata can interact symbiotically to form mycorrhizal associations with fungi such as Glomus intraradix, as well as create ectomycorrhizal associations with Alpova austroalnicola and Alpova diplophloeus.

Thanks to this symbiosis, the soils where Alnus acuminata is established can contain more minerals than other soils. In this way, the use of industrial fertilizers can be reduced.

References

Becerra, A., Menoyo, E., Lett, I., Li, Ch. 2009. Alnus acuminata in dual symbiosis with Frankia and two different ectomycorrhizal fungi (Alpova austroalnicola and Alpova diplophloeus) growing in soilless growth medium. Symbiosis 47: 85-92.
Virtual catalog of flora of the Aburrá Valley. 2014. Alnus acuminata. Taken from: catalogofloravalleaburra.eia.edu.co
Conabio. 2019. Alnus acuminata. Taken from: conabio.gob.mx
Tropics. 2019. Alnus acuminata Kunth. Taken from: tropicos.org
Catalog of Life. 2019. Species details: Alnus acuminata Kunth. Taken from: catalogueoflife.org

AILE: CHARACTERISTICS, HABITAT AND ECOLOGICAL ASPECTS - BIOLOGY - 2024