Conserving forests to
conserve their genes
in Pará state, Brazil. Tropical forests can
contain a very large number of tree species in a
small area, so there is serious loss of genetic
resources from their destruction.
Fire damage in Pará state, Brazil. Tropical forests can contain a very large number of tree species in a small area, so there is serious loss of genetic resources from their destruction. (FAO/15891/G.Bizzarri)
Forests face a wide range of threats, from the degradation caused by fires to the deforestation resulting from encroachment by agriculture. These not only threaten the forest as a productive resource but may reduce the number of species, especially in tropical areas where many tree species may be found in a small area.
The Panel also reiterated the importance of maintaining a high level of genetic diversity to ensure healthy tree populations. And it noted the need for institutions to collaborate on the conservation and exchange of genetic materials.
The Panel, established in 1968, meets every two years. It reports on the state of forest genetic resources and makes recommendations for their conservation and use. Its 15 members have expertise in a wide variety of forest environments and are from an equally wide range of cultural, linguistic and regional backgrounds. They don't represent their countries -- they are independent and eminent in their field.
The Panel's full report, which will be published early in 2002, will also highlight the following points:
In addition to information management, FAO's forestry work includes assistance to countries to better assess and manage genetic resources and support to specific programmes and species.
Why conserve forest genetic resources?
But diversity is important because the potential of many plants -- for wood and other products such as medicine -- is still largely unexplored. And genetic variation within species is important because growth and resistance to stresses such as harsh weather and disease depend on such variation. Tree populations that are genetically uniform won't grow as well over the varying environments that forests occupy and will face more difficulty in evolving to cope with changing environments. Intensive breeding encourages uniformity, so a reservoir of new genes needs to be constantly available to meet new problems.
If attention is not paid to managing this reservoir, it may also be threatened by the natural evolution of forest ecosystems. In places like Brazil, home to as many as 400 tree species per hectare, the fitness and pattern of a forest is therefore especially important to conserving diversity.
Nothing in nature is static. An old growth forest is not stable or permanent, but one in which certain species have triumphed -- to the detriment of many others.
"It is hard to quantify and monitor changes in biodiversity, including genetic diversity," says Pierre Sigaud, FAO expert on forest genetic resources. "The extent of forest area doesn't tell us everything." For example, plantations might replace natural forest, reducing species diversity. But by reducing logging pressures on the remaining natural forest, they may promote as much diversity as they destroy.
Even where parts of the natural forest are lost to agriculture, the genetic loss will depend on the extent of fragmentation of the remaining forest -- if it has been broken into small islands, species may be in small groups and therefore could fall below critical mass and eventually disappear.
"Factors like that don't respect borders," says Dr Sigaud. "The advantage of the Panel is that it works across them. And that makes it all the more unique and important."
12 February 2002