Climate change: Impacts on UK forests - Chapter 8
By Hugh Evans, Nigel Straw and Allan Watt
Key findings
- Climate change is likely to alter the balance between insect pests, their natural enemies and their hosts; predictions of the impact of climate change on insect damage to UK forests are therefore difficult to make.
- One of the most important effects of climate change will be to alter the synchrony between host and insect pest development, particularly in spring, but also in autumn; the predicted rise in temperature will also generally favour insect development and winter survival, although there will be some exceptions.
- The green spruce aphid is one example of an insect that is likely to benefit from the increase in winter survival, leading to more intense and frequent tree defoliation. A decline in the productivity of Sitka spruce might therefore be expected.
- Modelling work suggests that under a warmer climate, exotic pests such as the southern pine beetle could establish populations in Europe, and that climatic warming could make UK forests susceptible to damage; other bark beetles such as Ips typographus, which is present in some parts of Europe, but not the UK, could become a serious problem.
- Rising atmospheric CO2 concentrations may lead to a decline in food quality for plant-feeding insects, as a result of reduced foliar nitrogen levels.
- The planting of exotic tree species may exacerbate the beneficial effects of climate change on insect pests, as the natural predatory fauna may not be present to limit population growth.
- Changes have already been observed in the distribution of native European butterfly populations, with northern ranges extended and southern ranges reduced. The same is likely to be the case for forest insect pests.
- The combined effects of increased global trafficking of timber and wood products and climate change are likely to result in exotic pests such as Asian longhorn beetle becoming more prevalent; it is therefore essential that we remain vigilant in reporting new pests and altered patterns of damage.
Next: Chapter 9 - The impacts of increased CO2 concentrations on tree growth and function
Previous: Chapter 7 - Effects of climate change on fungal diseases of trees
