DRY FOREST: CHARACTERISTICS, FLORA, FAUNA, CLIMATE, RELIEF - ENVIRONMENT - 2025

The dry forest or dry forest is a plant formation with a predominance of the tree biotype in subtropical and tropical lowland climates. This jungle is characterized by presenting a prolonged hot dry season that occurs in the period corresponding to the astronomical winter.

It is one of the most threatened biomes, since in general it occupies the most suitable areas for the establishment of human settlements. In addition, it has land suitable for agriculture and livestock and has been a traditional source of wood and firewood.

Dry forest in Trinidad and Tobago. Source: FB Lucas

Currently it is estimated that there are about one million square kilometers of tropical dry forest worldwide. Of this extension, about 54% is in South America.

The determining factor for the formation of dry forests is the climate and the soil, in addition to a dry season that reaches 3 to 5 or more months in the winter. The soils are of medium fertility, without major restrictions on radical development.

This type of forest has a less complex plant structure than the tropical rain forest. Different types of dry forests such as thorns or deciduous forests can occur. In the case of semi-deciduous forests and monsoon forests, they have sources of groundwater or higher rainfall and achieve greater development.

The thorn forests and deciduous forests have two layers and their canopy is low (6-12 m) and the semi-deciduous forests can have up to 3 and 4 layers and with trees up to 30-50 m.

The best represented family in most dry forests is Leguminosae, although bignoniáceas and malvaceae are also abundant. The fauna is varied, found in America felines such as the jaguar and puma, collared peccary, snakes, as well as various birds. While in Africa these jungles inhabit elephants, rhinos, giraffes and large predators such as the lion.

General characteristics

The dry forest or dry forest is a biome of the tropical and subtropical zones in lowlands with a bi-seasonal climate.

- Plant structure

The dry forests have a less complex structure than the tropical humid forest, with fewer strata and less epiphytism and climbing. In general, there are two to three strata, including an understory of herbs and shrubs that can range from sparse to dense.

Structure of a dry forest. Source: Adbar

Another characteristic of dry forests is that the height of the trees is much lower than in the case of the rain forest. Their size is between 6 to 12 meters, although in semi-deciduous forests they can reach heights of 30-50 m.

- Adaptive strategies

In jungles or dry forests, the limiting factor is water, which forces the vegetation to develop strategies to survive. These strategies revolve around the need to maximize efficiency in the use of water and can be isolated or combined.

Leaf expiration

One way to reduce water loss in the dry season is by shedding the foliage, as the plants perspire through the leaves. However, this does not stop representing inconveniences since these are the productive organs of the plant.

By losing the leaves, the plant needs to enter a state of decreased metabolism to save energy as much as possible (dormancy). On the other hand, when the rainy season arrives again, they must use a large amount of energy and matter to form new foliage.

Some deciduous or deciduous species are ceiba (Ceiba pentandra) in America and teak (Tectona grandis) in Asia.

Phreatophytes

Some species of dry forest plants are evergreen, keeping their leaves even in the dry period. They do this because they have a deep root system that allows them to access groundwater at great depths.

The species with this strategy are known as phreatophyte plants, such as the Cumaná olive tree (Capparis odoratissima).

Reserve structures

Another strategy in dry forests is the development of water reserve structures, either in stems or roots. Cactaceae, for example, store water in their succulent stems, which have mucilages that favor water retention.

On the other hand, there are plants that develop lignified roots capable of storing water, called xylopods.

Sclerophyllous

One way to reduce water loss through perspiration is to reduce the size of the leaves and reinforce them with rigid fabric (sclerenchyma).

Leaf blade reduction

In other cases, it is not the total size of the leaf that is reduced, but the leaf area exposed to solar radiation. Here it is a question of developing a compound leaf, that is, a leaf blade finely divided into flakes or pinnae.

- Types of jungles or dry forests

Depending on the severity of the dry period, type of soil and the characteristics of the water table, different types of jungle or dry forest are generated.

Jungle or xerophilous spinescent forest (Espinal or thorn)

In these dry forests the strategies of leaf reduction, sclerophilia and succulence predominate. Most species are evergreen, but with very finely divided compound leaves.

Espinar in Venezuela. Source: Juan Carlo Castillo Ortega

Strategies based on the transformation of leaves into thorns and succulent photosynthetic stems are also presented. These jungles or thorn forests are found in various areas of South America, continental Africa, and in Madagascar.

In general, species of thorny plants abound, which is why they are called espinal (Argentina) or espinar (North of South America).

Deciduous forests or forests

Here the dry season is prolonged, of 5 or more months and they are characterized by being jungles where more than 80% of the individuals lose all the foliage in the dry season. They can also occur in areas with a shorter dry period, but with mountainous relief.

In the latter case, the steep slopes combined with a predominantly sandy soil reduces water retention.

Jungles or semi-deciduous forests

In these jungles, at least 50% of the individuals present are evergreen, maintaining the foliage in the dry season. The dry season can last between 3 and 4 months or have sources of groundwater.

Jungle or monsoon forest

Monsoon forest. Source: 大漠 1208

It is a type of dry seasonal forest, similar to semi-deciduous forest but with greater structural development. They are similar in complexity to the tropical rainforest, with greater climber and epiphytism.

- Floor

Sandy, sandy loam or clay loam soils predominate, with medium fertility and moderate pH. Due to the fact that the precipitations are not very intense, these soils present low nutrient losses due to leaching or washing.

Rainforests cannot be established on shallow soils or with lateritic layers that limit root penetration.

- Location

The jungles or dry forests are present in tropical and subtropical regions of both hemispheres, dominated by the trade winds or by monsoons.

America

In the American continent, the dry forest is located from the north of the Yucatan Peninsula (Mexico), Central America, to South America.

In this area there is dry forest on the Caribbean coast and in the Colombian-Venezuelan plains. Similarly, on the Pacific coast of Ecuador and Peru and in the north of Argentina, in Paraguay and south and east of Brazil.

The largest extensions of dry forests continuously occur in Bolivia and Brazil (Caatinga and Cerrado).

Africa

The dry forest runs from the central western Atlantic coast and runs between the sub-Saharan savanna to the north and the rain forest to the south. Later it continues through the Rift Valley south to Namibia and expands into the African Plateau.

In this area it reaches the southeast coast, with enclaves in Ethiopia, Somalia, Kenya, Tanzania, Mozambique and Zimbabwe up to the island of Madagascar. Similarly, there are some areas of dry forest in Egypt to the northeast.

Indo-Asian and Australasian region

These are the typical monsoon climate rainforests, with the seasonality determined by the monsoon winds. Dry forests are found in Pakistan and India as well as in Thailand, Laos, Cambodia, Vietnam, and southeastern China and in northern and eastern Australia.

Flora

Rainforests or dry forests are less biodiverse than humid tropical forests, yet they still have a large number of plant species. In some cases they are particularly rich in endemic species.

- Leguminosae or Fabaceae

The Leguminosae family is the most common in all dry forests worldwide. These include species from the group of mimosoids that are characterized, among other things, by presenting finely divided leaves.

In America

Species of the genera Acacia, Pithecellobium, Prosopis, Albizia, among others, are common.

In Africa

In the Zambian region the forest of mopane (Colophospermum mopane), an endemic legume, extends. The mopane forests are low, with a heights of 8 meters or less that include other legumes, especially of the Acacia genus.

- Malvaceae

Also called Bombacaceae. Another characteristic group of plants are the bottle trees of the Malvaceae family, named for their thickened, curved trunk (paquicaules). In America there is the ceiba (Ceiba pentandra), while in Africa we find the baobab (Adansonia spp.) And in Australia the Brachychiton populneus.

- Monsoon forest

Teak (Tectona grandis, Verbenaceae) and various species of bamboo (grasses of the subfamily Bambusoideae) are found in India and Southeast Asia. Also characteristic are mango (Mangifera spp.), Neem (Azadirachta indica) and mahua (Mahua longifolia) species.

Fauna

The thorns or xerophilous spinescent forests do not host a very numerous fauna, due to their extreme conditions of temperature and water deficit. However, in deciduous forests and, even more so, in semi-deciduous forests, the fauna is abundant.

- Mammals

Felines such as the jaguar (Panthera onca), the puma (Puma concolor) and the ocelot (Leopardus pardalis) are found in the dry forests of South America.

Also inhabiting these forests are primates such as the red howler monkey (Alouatta seniculus) and wild pigs such as the collared peccary (Pecari tajacu). Likewise, the most numerous mammals are various species of bats and rodents.

Mopane forest in Africa

Here live elephants (Loxodonta africana), giraffes (Giraffa camelopardalis), black rhinos (Diceros bicornis) and white rhinos (Ceratotherium simum) that feed on mopane. Likewise, it is possible to get warthog (Phacochoerus sp.) And different species of zebra (Equus spp.).

Elephant (Loxodonta africana). Source: Charles J Sharp

Among the great predators, the lion (Panthera leo) and the leopard (Panthera pardus) stand out.

- Birds

Among the birds of the South American dry forests are the guacharaca (Ortalis ruficauda) and the turpial (Icterus icterus). In Africa there are the ostrich (Struthio camelus), various species of vultures (genera Torgos, Trigonoceps and Gyps) and the martial eagle (Polemaetus bellicosus).

- Reptiles

There are species of poisonous snakes of the genus Bothrops and turtles such as the morrocoy (Chelonoidis carbonaria).

Weather

Rainforests or dry forests develop in bi-seasonal tropical climates with a marked and prolonged dry season. The maximum precipitation in these forests occurs in the summer period.

Precipitation

Average rainfall is medium to high, varying between 600 mm and up to 2,000 mm. However, although rainfall is high, there is always a dry period of 3 to 5 months or more.

Temperature

In all types of dry forests, average temperatures are high, above 25 ºC.

Relief

Dry forests occur in varied reliefs, from plains, intramontane valleys, plateaus and mountainous areas. They are located between sea level and a maximum height of 600 meters above sea level, below the orographic condensation zone.

In the leeward mountainous areas, dry forests can occur at higher altitudes (700-800 masl).

Dry jungle in Mexico

As Mexico is further from the equator, its territory is drier and therefore more conducive to the development of the dry forest. That is why more than half of the Yucatan peninsula is covered in this type of jungle.

It is a jungle with a long dry period of 5 to 8 months, which is found from sea level to 2,000 meters above sea level.

- Tree species

Legumes and burseráceas

In the dry forests of Mexico there are many species of legumes and burseráceas. Among the legumes, the quebracho (Lysiloma divaricata), the chaparro (Acacia amentacea) and the huizache (Acacia constricta) stand out. While among the burseráceas we have the Chinese copal (Bursera bipinnata) and the holy copal (Bursera copallifera).

Malvaceae and palms

Another family with prominent representatives is Malvaceae (Bombacoideae subfamily) with poppy (Pseudobombax palmeri) and pochote (Ceiba aesculifolia). Likewise, the palms with the coyol (Acrocomia aculeata) and the guano palm (Sabal japa).

Cactaceae

In the driest areas there are various cacti such as roofs (Neobuxbaumia tetetzo) and candelabra (Pachycereus spp.).

- El Nixticuil Forest

Its location in North America determines that in Mexico there is also dry forest with dominant temperate zone species. In Guadalajara there is a stronghold of what was once a more extensive dry forest, the El Nixticuil forest.

El Nixticuil Forest (Mexico). Source: Salvabosquetigre2

This seasonal dry forest is dominated by oaks and oaks, fagaceae of the genus Quercus. In addition, other species such as palo dulce (Eysenhardtia polystachya) and copal (Bursera spp.) Are present.

Dry forest in Colombia

The Colombian jungle or dry forest occupied large areas of the country, however, today only about 8% of these areas remain. This due to agricultural, livestock and urban pressure.

Dry forests are found on the Caribbean coast and in the plains (valleys of Patía, Arauca and Vichada). As well as in the Andean intra-montane valleys of the Cauca and Magdalena rivers, as well as in the department of Santander.

Biodiversity

These forests present a great biological diversity with around 2,600 species of plants and 230 species of birds and 60 of mammals. Some very well represented families in these forests are legumes, cacti, bignoniaceae and malvaceae.

Tree species

Among the tree species that inhabit the Colombian dry forests are the cumalá (Aspidosperma polyneuron), the cruiser (Platymiscium pinnatum) and the snail (Anacardium excelsum). Also the ear (Enterolobium cyclocarpum), the chicalá (Handroanthus ochraceus) and the igüá (Albizia guachapele).

Dry forest in Peru

In Peru the jungles or dry forests are found on the Pacific coast, towards the western slope of the Andean mountain range. They are equatorial forests, whose best expression is the Tumbes Region to the north, from the Gulf of Guayaquil to the La Libertad region.

This jungle, shared with Ecuador, penetrates into the Peruvian interior in the Marañón valley, up to 2,800 meters above sea level. It is a relatively low deciduous forest (8-12 m) with some outstanding species such as the ceiba (Ceiba pentandra) together with cacti, legumes and grasses.

Seasonally dry inter-Andean jungles or forests

Deciduous dry forests are also found in the Andean intramontane valleys between 500 and 2,500 meters above sea level. In general, they are two-layer forests, with a low tree canopy (7-8 m high) with an abundance of arborescent cacti and legumes.

Dry forest in Ecuador

In Ecuador there are about 41,000 hectares of jungle or dry deciduous forest, sharing with Peru the equatorial dry forest of Tumbes. The highest percentage of Ecuadorian dry forest is in Loja, in the canton of zapotillo.

Characteristic trees

Among the tree species that inhabit these equatorial dry forests are the Guayacanes (Handroanthus chrysanthus) of the Bignoniaceae family. There are also the ceibos (Ceiba trichistandra) of the Malvaceae, with their characteristic barrel-shaped trunk.

Dry forest in Ecuador. Source: No machine-readable author provided. Alfredobi assumed (based on copyright claims).

Legumes are another well-represented group, with species such as the carob (Prosopis juliflora) and the almond (Geoffroea spinosa). Other species are the palo santo (Bursera graveolens), the muyuyo (Cordia lutea) and the hawthorn (Pseudobombax millei).

Dry forest in Argentina

In the north of Argentina, in the region called the Chaco that it shares with Paraguay and Bolivia, there are large areas of dry forest.

The Argentine Chaco region

Although geologically it forms a continuity with the pampas, it differs in climate and ecology. Only two seasons occur in the Argentine Chaco, the dry and the rainy, with warm temperatures and dry forests develop.

Spinal

From the northeast to the center of Argentina there are areas of xerophytic vegetation dominated by spinescent species (Prosopis, Acacia and others).

Characteristic trees

Among the tree species typical of the Chaco are the red quebracho (Schinopsis balansae) and the white quebracho (Aspidosperma quebracho-blanco). The carob tree (Prosopis alba), the lapacho (Handroanthus impetiginosus), chañar (Geoffroea decorticans), and the black guayacaú (Caesalpinia paraguariensis) also flourish.

Palms are also abundant in this region, such as the yatay (Butia yatay), the pindó (Syagrus romanzoffiana) and the caranday (Trithrinax campestris).

Dry forest in Venezuela

Espinar

In semi-arid areas, the thorn-cardonal grows, named for the predominance of small trees and thorny bushes and columnar cacti (cardones). This formation is found mainly in the Lara and Falcón Depression to the northwest, and in the Unare Depression to the northeast.

Here, arborescent cactus species predominate, such as the lefaria cardon (Cereus repandus) and the dato cardon (Stenocereus griseus). In the sparse and sparse understory there are globose sub-shrub cacti such as the crop (Melocactus curvispinus) and the buchito (Mammillaria mammilaris).

Legumes such as cují yaque (Prosopis juliflora) and yabo (Parkinsonia praecox) also abound.

Deciduous forest

All along the Cordillera de la Costa, to the north of the country and in the plains to the south, there are deciduous montane forests. These are low forests (6-9 m) with a dry period of around 6 months and average temperatures of 27 ºC.

Legumes, Malvaceae, Cactaceae and Bignoniaceae abound in these forests. Finding species such as the yacure (Pithecellobium dulce), the araguaney (Handroanthus chrysanthus) and the vera (Bulnesia arborea).

Semi-deciduous jungle

In the western plains, extensive semi-deciduous forests developed which, thanks to high water tables and large rivers, had a high canopy. Unfortunately most of these forests have been devastated for the extraction of wood and the establishment of livestock and agriculture.

Today there are some relatively protected areas in forest reserves such as Caparo in Barinas state. Large fine wood species such as cedar (Cedrela odorata) and mahogany (Swietenia macrophylla) are found in these forests. Like the linnet (Cordia alliodora) and the saqui saqui (Bombacopsis quinatum).

References

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