Deforestation reduces rainfall in Africa

Sep 19, 2011

Deforestation in the rainforests of West Africa reduces rainfall over the rest of the forest, according to new University of Leeds research published in Geophysical Research Letters.

The study shows that changing land use from forest to crop land reduces rainfall over neighbouring trees by around 50% due to changes in the surface temperature which affects the formation of rain clouds.

The authors say the findings have important implications for future decisions about land management in this region and other global rainforests such as the Amazon.

Lead author of the study Dr Luis Garcia-Carreras, from the University of Leeds School of Earth and Environment, said: "We already know from that changes in land use can have a big impact on patterns. Here we have been able to show why this happens.

"Our findings suggest that it's not just the number of trees removed that threatens the stability of the world's rainforests, the pattern of deforestation is also important."

The forests of West Africa and the Congo Basin are the second largest in the world after the . They are important not only as a habitat for a vast and diverse ecosystem but also as a carbon sink, removing a large proportion of the CO2 in the Earth's atmosphere and slowing down .

For many years deforestation has been occurring widely in Africa, with being removed in favour of agriculture, plantations and other non-forest uses.

While the direct removal of trees has an immediate impact on the forest, this new study suggests that there also may be a secondary effect caused by the reduced rainfall.

"African rainforests already have the lowest rainfall of any on Earth, which could make them particularly sensitive to changes in local ," said Dr Garcia-Carreras.

"Therefore if rainfall is reduced even further as a result of deforestation, it could threaten the survival of the remaining forest by increasing the trees' sensitivity to drought."

To investigate the effects of different vegetation on locally-produced rain in , the researchers used a Met Office computer model to simulate rainfall under different land-use conditions.

They found that while the total amount of precipitation was largely unaffected, rainfall was four to six times higher over warm areas (cropland) than when no deforestation has occurred, while rainfall over the remaining forest was half or less.

The difference in rainfall is caused by the temperature change between cropland and forest, which produces winds that converge over the crop area and form clouds.

Study co-author Professor Doug Parker, also from the University of Leeds, added: "While our study only focussed on a small region in Africa, it's reasonable to suggest that this mechanism could be common in other global forests based on similar observations of rainfall in Amazonia."

 "This has implications for planners in terms of how deforestation is managed. If forest must be removed to create cropland, we need to think about what are the shapes and distributions of deforestation that will be least damaging to the adjacent forests and national parks."

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More information: 'How does local tropical deforestation affect rainfall' by L Garcia-Carreras and Douglas J Parker is published in Geophysical Research Letters doi:10.1029/2011GL049099

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Thanos251
not rated yet Sep 19, 2011
That is why it is best to practice Agroforestry. You can google "Agroforestry" and find many articles about how important Agroforestry is and how it is prefer over regular farming practice.

You can check out the Wikipedia article about Agroforesty for an example of how it can benefit crop & climate change at http://en.wikiped...forestry
Sin_Amos
not rated yet Sep 19, 2011
I've been a proponent of developing rainforests on the coasts of California to bring in rain to crops behind them forever. All that concrete is a waste of space as development destroys potential.
Jagadeesh
not rated yet Sep 20, 2011
To maintain ecological balance afforestation on a massive scale is the answer. In this connections Nations can emulate China Example.

Forest covered 9% of China's territory in 1949. The coverage has increased to 16% now and is project to reach 20% in 2020.

The global forest coverage is dwindling by 17 million hectares each year.

Each year, China creates 5.3 million hectares of forests, afforests another 3.7 million hectares of mountains where hunting and grazing are prohibited, and plants 2.4 billion trees by advancing the compulsory tree-planting campaign. These efforts have stabilized the coverage of the nations manually planted forests at 33 million hectares, and China now ranks first in the world in both the speed and scale of afforestation. The countrys current forest coverage rate is nearly 6 percentage points higher than what it was in the early 1950s.

Dr.A.Jagadeesh Nellore (AP), India
E-mail: Anumakonda.jagadeesh@gmail.com
Jagadeesh
not rated yet Sep 20, 2011
To maintain ecological balance afforestation on a massive scale is the answer. In this connections Nations can emulate China Example.

Forest covered 9% of China's territory in 1949. The coverage has increased to 16% now and is project to reach 20% in 2020.

The global forest coverage is dwindling by 17 million hectares each year.

Each year, China creates 5.3 million hectares of forests, afforests another 3.7 million hectares of mountains where hunting and grazing are prohibited, and plants 2.4 billion trees by advancing the compulsory tree-planting campaign. These efforts have stabilized the coverage of the nations manually planted forests at 33 million hectares, and China now ranks first in the world in both the speed and scale of afforestation. The countrys current forest coverage rate is nearly 6 percentage points higher than what it was in the early 1950s.

Dr.A.Jagadeesh Nellore (AP), India
E-mail: Anumakonda.jagadeesh@gmail.com
Jagadeesh
not rated yet Sep 20, 2011
To maintain ecological balance afforestation on a massive scale is the answer. In this connections Nations can emulate China Example.

Forest covered 9% of China's territory in 1949. The coverage has increased to 16% now and is project to reach 20% in 2020.

The global forest coverage is dwindling by 17 million hectares each year.

Each year, China creates 5.3 million hectares of forests, afforests another 3.7 million hectares of mountains where hunting and grazing are prohibited, and plants 2.4 billion trees by advancing the compulsory tree-planting campaign. These efforts have stabilized the coverage of the nations manually planted forests at 33 million hectares, and China now ranks first in the world in both the speed and scale of afforestation. The countrys current forest coverage rate is nearly 6 percentage points higher than what it was in the early 1950s.

Dr.A.Jagadeesh Nellore (AP), India
E-mail: Anumakonda.jagadeesh@gmail.com
pres68y
not rated yet Sep 20, 2011
Seems like the Chinese have figured it out!
Our misinformed groups even think fire is a better solution
-besides willingness to enact deforestation.
e.g. So Africa removes trees thinking it will save water instead of providing more rainfall... what a poor analysis.
Shootist
1 / 5 (1) Sep 20, 2011
I've been a proponent of developing rainforests on the coasts of California to bring in rain to crops behind them forever. All that concrete is a waste of space as development destroys potential.


Fortunately you are not in charge.

"Forget left or right, monarchist or fascist, there are two types of people in the world, those who would control the actions of others and those who have no such desire." - Robert Heinlein
deepsand
2.9 / 5 (11) Sep 20, 2011
I've been a proponent of developing rainforests on the coasts of California to bring in rain to crops behind them forever. All that concrete is a waste of space as development destroys potential.


Fortunately you are not in charge.

"Forget left or right, monarchist or fascist, there are two types of people in the world, those who would control the actions of others and those who have no such desire." - Robert Heinlein

Relevance to the cited member's statement?