New research shows half of farmlands globally have tree cover
by IBC ~ August 26th, 2009. Filed under: Conservation.NAIROBI, Aug. 24 (Xinhua) — Although agriculture, particularly in the developing world, is often associated with massive deforestation, a study done by scientists from the World Agroforestry Centre detailing satellite imagery, says almost half of all farmed landscapes worldwide include significant tree cover.
Remnant trees in farmlands and settlement areas
The findings were announced on Monday at the opening of the 2ndWorld Congress of Agroforestry, which is being held in Nairobi, Kenya this week. This is the first study to quantify the extent to which trees are a vital part of agricultural production in all regions of the world. It reveals that on more than one billion hectares — which makeup 46 percent of the world’s farmlands and are home to more than half a billion people — tree cover exceeds 10 percent.
“The area revealed in this study is twice the size of the Amazon, and shows that farmers are protecting and planting trees spontaneously,” said Dennis Garrity, the Centre’s Director General.
“The problem is that policymakers and planners have been slow to recognize this phenomenon and take advantage of the beneficial effect of planting trees on farms. Trees are providing farmers with everything from carbon sequestration, to nuts and fruits, to windbreaks and erosion control, to fuel for heating and timber for housing.”
Garrity says unless such practices are brought to scale in farming communities worldwide, “we will not benefit from the full value trees can bring to livelihoods and landscapes”.
The World Agroforestry Centre is one of 15 centers supported by the Consultative Group on International Agricultural Research (CGIAR).
From the data presented in the study, it is not possible in all cases for the researchers to discern precisely the products and services that trees are providing.
However, a great deal of previous agroforestry research has documented a wide range of uses for trees on farms, including: fertilizer trees for improving crop yields and enhancing soil health; fruit trees for nutrition; fodder trees to feed livestock; timber and fuel wood trees to provide shelter and energy; medicinal trees; and trees that provide global commodities such as coffee, rubber, nuts, gums and resins.
As equally important on the service side are uses such as erosion control, water quality and biodiversity.
“If planted systematically on farms, trees could improve the resiliency of farmers by providing them with food and income,” said Tony Simons, Deputy Director General at the World Agroforestry Centre.
“For example, when crops and livestock fail, trees often withstand drought conditions and allow people to hold over until the next season.”
“What trees essentially provide to farmers is choice. Choice of enterprise, choice of market, choice for diversification, choice for low labour requirement, choice for multiple function,” Simons says.
“Developing country farmers are spoilt for choice. Whilst Western Europe has some 250 native tree species and North America has a larger set of 600 tree species, the developing tropics has a staggering 50,000 tree species to manage and utilize. The priority is to find the right tree for the right place for the right use.”
Previous estimates for the amount of farmland devoted to agroforestry have ranged from as low as 50,000 hectares to as high as 307 million hectares.
But these estimates were not derived from detailed remote sensing data as was employed in this assessment.
In this study, scientists were able to measure the amount of tree cover on each square kilometer of the world’s 22.2 million square kilometers of farmland.
The scientists — who included researchers from the International Center for Integrated Mountain Development and the Katholieke Universiteit Leuven in Belgium — found that about 10 million square kilometers of agricultural land have at least 10 percent tree cover.
That includes 3.2 million square kilometers in South America, 1.9 million in sub-Saharan Africa and 1.3 million in Southeast Asia. According to the report, “trees are an integral part of the agricultural landscape in all regions, except North Africa and West Asia”.
Their data also show that people live with trees in farmed landscapes in virtually all of Central America, and in about 80 percent of such landscapes in Southeast Asia and South America.
The proportion was lower but still large in sub-Saharan Africa, Europe, and North America, where trees are a significant feature on about 40 percent of agricultural land.
The study observes that the extent of trees in farmland in North America and Europe is especially impressive, given the large commercial agricultural sector of these regions.
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