Woodlands and forests contain substantial carbon (C) in the soil, trees and other vegetation, and globally they are hugely important to the carbon, water and energy cycles. Removing forests releases CO2 into the atmosphere, while growing trees absorb CO2 from the air. Other greenhouse gases (GHG) such as methane and nitrous oxide are also exchanged between forests and the atmosphere, so forests are a key component of the planet’s GHG balance. Therefore the functioning and management of forests are critical to efforts to reduce climate change (‘climate change mitigation’), and reduce the net GHG emissions into the atmosphere (‘emissions abatement’).
UK forest carbon balance
In the UK, the amount of C held in woodlands and forests is estimated at approximately 880 Mt C (million tonnes of carbon). While the large amounts of carbon in the trees are most obvious to us in the stems and woody roots, over 75% of UK forest C is held in the soil (down to 1 m only; peat soils in some locations may be much deeper). This amount of C in forests is equivalent to about 7-10 years of our present UK fossil fuel emissions, and over 25 times the target annual CO2 emissions for the UK for the year 2050. Conversely, if the amount of C held in UK forests or in long-lived forest products like timber could be increased then this would help reduce net GHG emissions. In addition, harvesting trees for wood fuel for heating or power generation instead of using fossil fuels, can cause a net emissions reduction, if the rate of growth of replacement trees is sufficient to absorb the CO2 released during wood fuel production and consumption.
Research on forestry and climate change mitigation
Forest Research has had several research projects over some years examining the above issues, in particularly in measurement of forest C stocks and CO2 exchanges, modelling of forest C balances at both stand and national scales. Recognising the importance of forestry C and GHG issues to the Forestry Commission and to the UK forestry sector, several of these projects were drawn together in 2009 to form an integrated programme on managing Forest C and GHG balances.
There are also links to another main climate change research programme on Adaptation, as obviously future climate change mitigation will depend on measures taken to adapt woodlands, forests and forestry to the changing climate.
The evidence gathered in the research is used to inform policy directly and is disseminated through several publications, including research reports, forestry sector journal and magazine articles, and academic articles. We also collaborate with organisations increasing public awareness of forestry carbon, GHG and management issues, such as the OneOak project.
Indirectly, many of our other research programmes underpin the general question about the role of forestry in climate change mitigation – for example work on forest management and silviculture can inform on rates of C uptake and timber production; and research on tree health is key to understanding growth rates and C stock longevity.