Treeline in Sahel

 

Desertification. It is quite a concern to the entire world. Dry areas cover more than one third of the Earth's land surfaces.Those areas which are not already deserts, are in the process of being degraded by the sand.

(The topic was covered before in a previous program, Fighting Desertification, if you wish to use it as a make-up meeting.)

 

Sahel


Sahel region 
Source: Wikimedia.org

Sahel is the ecoclimatic and biogeographic zone of transition, in Africa, between the Sahara desert to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the southernmost extent of Northern Africa, spanning 5,400 km (3,360 mi) between the Atlantic Ocean and the Red Sea. The meaning of the word in Arabic means shore or coast. In this case it is used to describe the separation between Sahara's sand to the north and the savanna to the south.

For hundreds of years, the Sahel region has experienced regular droughts and megadroughts. One megadrought, from 1450 to 1700, lasted 250 years. There was a major drought in the Sahel in 1914, caused by annual rains far below average, that caused a large-scale famine. From 1951 to 2004, the Sahel experienced some of the most consistent and severe droughts in Africa. The 1960s saw a large increase in rainfall in the region, making the northern drier region more accessible. There was a push, supported by governments, for people to move northwards. As the long drought-period from 1968 through 1974 began, the grazing quickly became unsustainable, and large-scale denuding of the terrain followed. Like the drought in 1914, this led to a large-scale famine, but this time it was somewhat tempered by international visibility and an outpouring of aid. Food insecurity in the Sahel region has been increasing annually due to crops failing because of lack of rainfall as well as a growing locust threat.

 

Trees for Survival

Of course, Rotary International was and is present in the region to help in different ways, either with shelter, clean water projects or helping disaster victims in any other way they can. An important Rotary Club initiative which started in 1991 was the "Trees for Survival" program. By 1994 the program had grown too big for the club to administer and the Trees for Survival Trust was formed. It currently still has the support of the Rotary Clubs of New Zealand.

Trees for Survival is an education program which involves young people growing and planting native trees to help landowners revegetate erosion prone land, improve stream flow and water quality and increase biodiversity. With over 5,000 school students involved and more than 70,000 trees planted each year they managed to plant more than a million trees in 20 years and counting.


Filao trees in the desert coridoor

Back to Sahel, every year, entire villages in the region are forced to move as the sands of the Sahara take over their land. Well-designed tree planting activities can halt and even drive back the sands of the desert. For example, in Senegal, a belt of filao (a fast-growing, drought and salt tolerant tree) planted decades ago has been protecting the region.

Unfortunately, planting trees in the Sahel region is not very efficient due to the economic situation of the region's inhabitants. Since they are poor, they tend to chop down the trees and use it for heat. Even in Senegal, heavy use of firewood has taken its toll and the dunes are on the march once again.

 

Dunes into architecture


Magnus preparing bacteria.

So what is there to do? Swedish architect, Magnus Larsson, teams up with the most unlikely partner to create a 6,000 kilometer-long inhabitable green sandstone wall along the Saharan desert. With the help of bacillus pasteurii, a bacterial microorganism abundantly available in marshes and wetlands, the loose sand will be transformed into a fibrous porous structure that will sustainably control desertification while housing thousands of refugees. The crux of the project however lies in the natural microbial reaction of the bacteria with the sand particles that turn them into organic dunes of structurally-sound sandstone, a process that has been studied at UC-Davis using the rock formations in Utah that follow the same principle - albeit on a much smaller scale. Intrigued? Please watch the video below to find out more:

 

Magnus Larsson: Turning dunes into architecture: 11:40 min (watch only until minute 11:40)

 

What are your thoughts on the idea?

 
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