Adaptation

Land management activities like forestry and agriculture are likely to be among the first to feel the effects of a changing climate. The challenge for forestry is to adapt to new threats and new opportunities while still maintaining sustainable forests and woodlands. The first response to the threat of climate change was to concentrate on mitigation to try to stop it happening. However, with the concentration of greenhouse gases in the atmosphere continuing to increase rapidly and climate models predicting more rapid rates of change, the need for adaptation strategies became evident. This shift of emphasis means that forest managers have to consider the ways in which forestry will have to cope with change as well as how it can help the drive to reduce emissions.

Forest managers have to consider whether their woodlands will survive in the new climate. We are not able to shift cultivation and crop type as easily as farmers but we are dealing with long-lived habitats that have their own natural adaptation mechanisms. All ecosystems have the capacity to react to change and, in response, to adjust. The extent to which a system is able to generate such adjustments is known as its adaptive capacity. Adaptation reduces the vulnerability of a system, limiting its susceptibility to the negative impacts of any change.

When a forest ecosystem is subjected to a changing climate, the responses of its component species depend on:

• the ability of an individual organism to acclimatise (referred to as phenotype plasticity)
• the capacity of a population to change its genetic make-up such that individuals are better suited to the changed conditions (referred to as adaptive evolution). This is a slow process for trees and woodlands.
• the ability of a population to move to a location where the conditions still suit it (referred to as migration). This is obviously not an option for individual trees but seed dispersal could allow a shift of range.

In addition to the effects on forest ecosystems, a changing climate will affect management operations. Increased winter rainfall could mean more difficult harvesting and extraction of timber; more severe rainstorms could increase risks of landslip and damage to forest roads and bridges. Increased summer temperatures may bring more visitors into the shade of the trees. Some of these changes can be accommodated by the current working methods and the normal resilience to weather of people who work in land management. Other risks may have to be assessed earlier for example, in some Forestry Commission forests action is already being taken to increase the capacity of roadside drainage systems.