Fraxinus uhdei or wild ash is an evergreen tree that belongs to the Oleaceae family. This plant can reach 30 meters high and present a compact crown. Ash is a native tree of Mexico with wide distribution in this and other countries of Central and South America.
Fraxinus uhdei is an arboreal growing plant with a median longitudinal range of 15-20 meters. The leaves of the ash tree usually measure 25 cm in length on average and the trunk is straight and develops ascending branches.
Juvenile of Fraxinus uhdei. Forest & Kim Starr
Ash flowers are unisexual and are grouped in panicles. The fruit is winged with a yellow-brown seed.
It is a tree native to Mexico, but it is possible to find it in other countries in the region, as well as South America. Its habitat corresponds to gallery forests with a temperate climate and is frequently associated with other tree species.
Ash is used as an ornamental tree and its wood is used for handicrafts and for the manufacture of agricultural implements.
characteristics
Tree
The ash is a dioecious perennial tree that usually grows up to 15 or 20 meters in height, being able to measure up to 30 meters in some individuals. The stem is straight and has an average diameter at chest height of 1 meter. Meanwhile, the F. uhdei cup has a rounded shape and a compact appearance distally.
Leaves
Ash leaves are pinnate compound and arranged alternately. Each leaf is 20 to 30 cm long and contains five to nine loose pinnae. Each pinna is ovate-lanceolate in shape and has an entire, serrated margin towards the apex.
Leaves of the Mexican ash tree. Forest & Kim Starr
flowers
Fraxinus uhdei flowers are unisexual and are grouped in large panicles 12 to 20 meters long. In addition, the flowers are devoid of petals and are pollinated by the wind. The female flowers consist of a calyx and a pistil. Male flowers contain two stamens with elongated anthers and a small calyx.
Inflorescence of Fraxinus uhdei. Forest & Kim Starr
Fruit
The fruits of the ash tree, called samaras, are elongated and contain flattened wings of fibrous tissue. These fruits develop in dense clusters measuring 15-20 cm in length. Each fruit contains a seed 2 to 6 cm long and 0.5 cm thick; also the seeds have a thin yellow-brown wing.
Taxonomy
- Kingdom: Plantae.
- Subkingdom: Viridiplantae.
- Infra kingdom: Streptophyte.
- Super division: Embriofita.
- Division: Tracheophyte.
- Subdivision: Eufilofitina.
- Infra division: Lignofita.
- Class: Spermatophyte.
- Subclass: Magnoliofita.
- Superorder: Asteranae.
- Order: Lamiales.
- Family: Oleaceae.
- Tribe: Oleeae.
- Subtribe: Fraxininae
- Genus: Fraxinus.
- Species: Fraxinus uhdei (Wenzig) Lingelsh.
Synonymy: F. americana L. var. uhdei Wenzig, F. cavekiana Standley & Steyerm., F. chiapensis Lundell, F. hondurensis Standley.
In turn, Fraxinus uhdei corresponds to the Melioides section, which includes fifteen North American species. In this way, ash is the only member of the Uhdei group. The distinction of the groups within the Melioides section correspond to geographic patterns.
Habitat and distribution
Fraxinus uhdei frequents the slopes and to a lesser extent the banks of rivers. In addition, it is common to find it in areas with temperate climates and it develops optimally in clay, sandy, fertile and very deep soils.
From an ecological point of view, this species is very important since it is the only one of the genus that is found in the wild and because it is associated with the ecological units of oak forest, gallery forest, pine forest and mountain mesophilic forest..
For its part, the ash tree is frequently associated with Alnus sp., Cedrela sp., Ceiba sp., Salix sp., Ipomoea sp., Juniperus sp., Quercus sp., Ficus sp., And Cestrum sp.
This species is also known as the Mexican tropical ash or wild ash and is distributed from central Mexico to Guatemala. In addition, this tree has been introduced as an ornamental street tree in other countries of the American continent.
Climatologically, this tree grows in regions with an average temperature of 15 to 25 ⁰C and with a precipitation range of 800 to 3000 mm per year.
Applications
Fraxinus uhdei is widely used in reforestation programs and as an ornamental tree on the streets of some cities. In crafts, this tree is used to make wooden toys and musical instruments.
In addition, Mexican ash is used to make agricultural instruments and to make tool handles. Because its wood is of good quality, this tree is exploited for the manufacture of fine furniture.
It is also used in traditional medicine, since its bark is rich in an alkaloid called fraxin, which has fever-reducing properties. Also, local people have used parts of this tree to treat malaria.
From the socioeconomic point of view, this tree brings benefits to beekeepers since its flowers are honey-bearing.
Diseases
The most recurrent disease affecting Mexican ash is leaf chlorosis, which is caused by an unidentified phytoplasma.
Symptoms of this disease include chlorosis of the leaves, abnormal growth pattern of the leaves, and crown growth at the stem and branch level in mature plants. This disease can kill entire populations of this species.
Other pests include insects and fungi, being anthracnose a disease of high incidence since it attacks various parts of this tree, causing widespread rot and later death.
Likewise, the ash bug (Tropidosteptes chapingoensis) can cause massive defoliation in young F. uhdei individuals. The loss of bark from mature Mexican ash plants is caused by Leperisinus fraxini. For their part, termites of the genus Kalotermes can cause severe damage to the wood of this tree.
References
- Wallander, E. 2008. Systematics of Fraxinus (Oleaceae) and evolution of dioecy. Plant Systematics and Evolution, 273 (1-2): 25-49
- Báez-Pérez, AL, Linding-Cisneros, R., Villegas, J. 2017. Survival and growth of nursery inoculated Fraxinus uhdei in acrisol gullies. Wood and Forests, 23 (3): 7-14
- Nesom, GL2014. Phylogeny of Fraxinus sect. Melioides (Oleaceae): review and an alternative hypothesis. Phytoneuron, 95: 1-9.
- Wallander, E. 2014. Systematics and floral evolution in Fraxinus (Oleaceae). Belgische Dendrologie Belge, 38-58
- The Taxonomicon. (2004-2019). Taxon: Genus Fraxinus L. (1753) (plant). Taken from: