Equatorial Climates

The equatorial climate lies in regions close to the equator. An abundance of plants and animals thrive in these regions.

Location

The equatorial regions are located within 0⁰ to 10⁰ north and south of the equator. Places in this region includes, the Amazon Basin in Brazil, South America, the Zaire Basin in West Central Africa, Indonesia and East Indies, specifically Borneo, New Guinea, Java and the Guinea Coast. Equatorial regions blend with wet and dry climates.

Climate & Temperature

Throughout the year, the climate is hot and wet generally, averaging 28⁰C. The diurnal range (the difference between maximum and the minimum temperature for the day) or daily temperature range is about 2 degrees Celsius. Rainfall and humidity is above normal particularly during the months of April and October during the equinoxes. Rainfall is generally convectional accompanied by thunderstorms.

Precipitation

The precipitation is heavy, often and well distributed through the year. There is no dry season with average annual rainfall being at 2000 to 4000 mm with daily averages of 100mm. There is a high humidity, over 80%.

Natural Vegetation

The natural vegetation in the equatorial regions is mainly equatorial or tropical rain forest.

The vegetation in the forest is dense, broad-leaved evergreen forest that is called selvas.

There are a wide variety of species of trees in a single location. They do not grow in extensive stands but in mixed varieties. The heterogeneous variety makes is difficulty for lumbering.  

The trees form layers according to their height called stratification. There are three distinct layers:
            A layer, the tallest, at 20 to 40 metres high

            B layer, 15 to 40 meters high

            C layer, the shortest, at 5 to 15 meters high

Other layers include, the (i) canopy and emergent layer and (ii) the forest floor.

The canopy or emergent layer is the tallest layer comprising of dense evergreen trees. These trees receives the most sunlight and forms a dense interlocking canopy of vines, leaves and branches that prevents the sun from reaching the lower layers.

The emergent layer grows through the canopy. These are a few taller trees that grow above the canopy and are called dipterocarps. 

The tree structures of the forest are straight, tall and often thick. Large spreading buttress roots support them. The roots spread out over three meters above the ground and burrow into the soil to support the large trees. The leaves are evergreen and dark green. Several types of hardwood trees such mahogany, ebony, rosewood, greenheart, and ironwood exists in the equatorial forests.

The under storey and forest floor consist of trees 5 to 15 meters tall. The lower levels receive very little rainfall. Only 10 per cent of rainfall reaches this layer.

The vegetation at this level consists of large leaves shrubs, fungi (exists without sunlight); mushrooms (a type of fungi).

Some of these ground level plants are saprophytes that live on decayed vegetation.

Ferns, mosses and orchids called ephiphytes anchor on trees and branches instead of the soil.

Woody creepers called lianas grow upwards on the trunk of trees.  

Mangrove forests exist along tidal estuaries and coastal areas of equatorial forests. The trees here are usually stilt or prop root trees.

Clearing forest areas for farming generates a secondary forest with mixed crops after it is abandoned. This type of forest is usually described as a jungle.

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