Changing rainfall patterns as a result of climate change

 

In a changing environment it is likely that there will be shifts in rainfall seasonal patterns. The UKCIP02 predictions indicate that:

• Winters are likely to become wetter
• Summers may become drier
• The relative changes will be largest in the south and east of the UK Heavy winter precipitation may become more frequent.

The figure below shows the UKCIP02 seasonal rainfall predictions (winter upper, summer lower) for the 2080s Low and High emission scenarios relative to the 1961-90 baseline:

Effects of wetter winters

• Winter waterlogging will affect the trafficability of forest soils and will limit access for harvesting machinery
• Forest on waterlogged soils are more prone to windthrow
• Waterlogging of soils leads to the death of fine roots, this can make the effects of high summer soil water deficits worse
• Infection by various soil-borne pathogens is promoted by fluctuating water tables.
  

How will the increased occurrence of summer drought conditions effect trees?

• Initially the establishment of young trees may become more difficult
• Eventually the suitability and distribution of some species will change
• Stress caused by drought will make trees more susceptible to pathogens
• The predicted increase in the severity and frequency of summer droughts are likely to have the most profound effects on trees and woodland of any of the climate change predictions, particularly in the south of the UK.

Snowfall

Snowfall and thus snow damage will become less frequent as a result of rising temperatures. However, concerns have been raised that wetter snow and heavier falls may cause more serious damage to tree crops, thus potentially counteracting the generally lower incidence of snow fall that is predicted.