Forests and water, a link that benefits man

Trees retain and regulate rainwater

The foliage of the trees intercepts the rainwater and prevents the direct impact of the drops on the ground, protecting it against erosion and waterlogging. It also provides shade to the ground and prevents its drying out. Tree roots support the ground and restrict landslides; They also favor the infiltration and use of deep groundwater, which in turn returns to the atmosphere through the evapotranspiration of the leaves, increasing the relative humidity and the probability of rains.

Thanks to the damping of rainfall and the retention of water in the soil, forests moderate the negative effects of heavy rains and facilitate water availability during periods of drought. Therefore, watershed forests play a key role in flood protection, and in water conservation and provision of that element to surrounding populations.

Many cities in the world have water thanks to the forests

The FAO, Food and Agriculture Organization of the United Nations, explains in its Toolkit for Sustainable Forest Management that “a large part of the world's drinking water comes from forested areas, and millions of people depend on good freshwater quality flowing from the forests. For example, the forests of the Uluguru mountains provide drinking water to the 2.5 million inhabitants of Dar es Salaam, the capital of Tanzania. Likewise, 1.3 million people in Quito and 20 million people in Mexico City get their drinking water from mountain forests.”

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The environmental organization Mongabay, in its article The inhabitants of Mexico City face the uncertain future of its Water Forest, states that “the Water Forest helps regulate the climatic problems created by man: urban forests, in particular, they are well known for filtering air pollutants, such as smog. It also safeguards the water cycle connected to two of the largest rivers in the country, the Lerma and the Rafts, and the aquifers that supply approximately two-thirds of the water in the metropolitan area. ”

Certain threats to forests put water availability at risk

The World Wide Fund for Nature (WWF), in its report Los Guardianes del Bosque, states that “deforestation occurs in many forms, including fires, indiscriminate logging for agriculture, livestock and project development, unsustainable logging of wood and degradation due to climate change. ”

In addition to the fires, which in the last year have destroyed in total millions of hectares of forests in Bolivia, Brazil, and Paraguay, an important threat is extensive livestock, which affects large wooded territorial areas, even within some protected natural areas. Livestock traps and tramples the newly born seedlings, and compacts and undresses the soil, thus favoring sheet erosion and sediment supply to courses and water mirrors, in addition to exposing the soil to the desiccant action of the sun and the wind, a phenomenon that in the long term reduces groundwater accumulated in aquifers, and restricts the infiltration of rainwater.

It is important to understand the delicate balance that exists between trees and water, and the ease with which we can alter it: a cigarette thrown over dry leaf litter is enough to cause a fire, devastate a forest, and alter both the quality and quantity of water available for wildlife and human populations.

Without water there are no forests; but without these, there is no water, and without it, our survival and that of other species is impossible.