Genetic diversity ensures that forest trees can survive, adapt and evolve under changing environmental conditions. It is vital to maintain the vitality of forests and to cope with pests and diseases. Despite their fundamental importance, forest genetic resources are under threat.
Forest genetic resources (FGR) are made up of the heritable diversity that underpins the evolution and adaptability of forests and trees. These trees are of actual or potential economic, environmental, scientific and societal value, but FGR refers not to the direct benefits of tree and forest resources but to the genetic aptitude that allows the trees and forests to deliver those benefits.
FGR constitute one part of the broader grouping of plant genetic resources for food and agriculture (PGRFA), defined as “any genetic material of plant origin of actual or potential value for food and agriculture”, which is generally taken to include forestry.
Forest genetic resources are also one component of forest biodiversity, which encompasses all the living (and dead) things in a forest and the ecological processes of which they are a part. In the same way that PGRFA includes FGR, so too agricultural biodiversity is taken to include forest biodiversity.
Genetic resources vary among forests, giving rise to different types of forest that contain different species. Genetic resources also vary within each species, resulting in differences that, for example, allow some individual trees to thrive with less water or higher temperatures than other individuals of the same species.
Forests provide us with many benefits, from the tangible economic returns of high-value timber to more nebulous but no less important ecosystem services, such as regulating water flows.
Forests provide human beings with drinkable water, food, medicines, an environment to enjoy and fuelwood for energy, among other goods. They bind soil on steep hillsides, preventing flooding and erosion further down river valleys. They help to regulate the local climate too. Globally, forests remove carbon dioxide from the atmosphere and produce oxygen.
While it is impossible to assign a precise economic value to forests, it is clear that their contribution is huge. In Europe, one estimate put the value of “marketed non-wood goods” from forests at €2.3 billion and the value of “marketed services” at €619 million (State of Europe's Forests 2015, p. 26).
The environmental value of forests – through the ecological services they provide, essentially for free – is probably even greater than the value captured by markets.
Forests are under threat, chiefly as a result of human activities, including climate change.
On a continent-wide scale, changes in rainfall patterns and temperature mean that some tree species will be unable to survive in their current locations. Others may be able to colonise new areas. Changes in climate also make it possible for pests and diseases to invade new areas, destroying the forests there. Overall, we can be sure that the composition and distribution of forests will change. It is because humans – and indeed the whole planet – derive so many benefits from forests and trees that we need to be concerned about how they will adapt to climate change.
Maintaining forests and ensuring that they can adapt to future climate and other challenges depends crucially on FGR.
Genetic diversity allows forests to recover from adversity, to respond and to reorganize. Only if forests can adapt will they be able to provide for human needs over the very long term.
Assigning a value to genetic resources is, if anything, even more difficult than assigning a value to forests and trees. In a few cases, it can be done. For timber, the use of selected sources of seed can increase yields by double or more. Resistance to pests and diseases of fruit trees may be found in their wild relatives.
Even without being able to calculate precise cost-benefit ratios, however, it is clear that conservation of FGR is absolutely crucial to allow forests to adapt to climate change and to thrive, meeting future human needs.