Forestry and climate change mitigation

Introduction

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.

Individual research projects

• Oak woodland carbon and greenhouse gas balance at the Straits Inclosure
• Spruce forest carbon and greenhouse gas balance at Harwood Forest
• Greenhouse gas dynamics in forests