Agroforestry for biodiversity
In Asia and other regions of the world, complex agroforestry systems, developed by farmers as enriched fallows over the last 100 years, help to preserve the biodiversity of wildlife. For example, in Sumatra, farmers have developed a sustainable agroforestry system which is both highly productive and extremely diverse in the plant and animal species that lie within it. These agroforests closely resemble natural forests with their wide variety of tree, bird and mammal species, including the black-handed gibbon and the Sumatran rhino which are both endangered species.
These agroforests, which form a contiguous block of about 10,000
hectares, are not a relic of a former culture, they have been planted
over the past century by 
farming
families who each have about two hectares. This is a response by
modern farmers to the disappearance of forests and the commercially
valuable species they contain. The farms are established when natural
forest is cleared to cultivate rainfed rice, coffee, bananas, and
peppers. But in this case, damar (Shorea javanica), and a
range of other indigenous trees that produce fruits and timber, are
interplanted amongst the crops and in effect create a cash-crop fallow
which may provide products for 30-50 years. For the first ten years
farmers' income is provided by the sale of products from food
crops. Later, as the trees mature, they shade out the much smaller -
lower-storey - plants. The whole system thus becomes an agroforest
that produces fruits, vegetables, nuts, medicines, timber and the
higher value damar resin, which is sold and used internationally in
the manufacture of paints, varnish and incense. In Indonesia, the
total income made by these farmers from the sale of the damar resin
alone is about US $7.5 million per year. In good seasons, fruits, such
as the duku (Lansium domesticum), are produced in great
quantities and also provide additional employment and extra income for
local villagers.
These complex agroforests become a climax agro-ecosystem which is profitable and rich in the diversity of life, unlike plantation monocultures, and are an excellent example of an indigenous landuse system which conserves diversity while providing a wealth of products. ICRAF says that it should be possible to use this specialized form of agroforestry as a model that could be copied in other regions of the moist tropics. In fact, experiments have already started in the Amazon and, according to Dr Leakey of ITE (former Director of Research, ICRAF), initial trials and economic evaluations have been very promising. He is also hoping that countries in the humid areas of West Africa may also benefit from this example. By using indigenous species of the region to establish agroforests, similar to those in Sumatra, it should be possible to provide the particular products required by local people, as well as to conserve the genetic diversity of species which originate in the forests of West Africa.
ITE (Institute of Terrestrial Ecology, UK)
