Creating woodlands and targets for planting trees are important parts of the Climate Change Plan update to contribute to greenhouse gas (GHG) reduction targets.

Agroforestry combines trees and agriculture on the same plot of land, with tree density varying dependent on agricultural land type, tree species and objective. There has been growing interest in agroforestry systems as an opportunity to integrate land management objectives and contribute to meeting tree planting targets and generate GHG reductions and removals. However, currently a very small proportion (3.3%) of the area used for agriculture in the UK is managed as agroforestry. Carbon schemes, such as the Woodland Carbon Code (WCC) could offer a potential route to provide financial support and incentivise agroforestry.

This reports assesses the potential to reduce greenhouse gas emissions through different forms of agroforestry. 

It finds that all forms of agroforestry have the potential to sequester carbon, although the benefits will vary depending on soil type, species, planting density and location.

The research suggests that the fastest rate of carbon sequestration is most likely to be achieved on highly productive lowland areas. Whilst benefits can also accrue on less productive uplands, avoiding disturbance of organic soil layers is a key consideration.

Drought, as a significant risk to Scottish forests, is likely to be exacerbated by the changing climate. This report summarises the current state of research, describes ongoing projects and identifies knowledge gaps and potential research directions. Considerations around the policy and practice implications are made, taking into account the available information.

Key findings

• There is high confidence that especially in east, central, and south Scotland the direct effects of severe droughts are likely to be felt primarily in forest productivity and carbon sequestration. 
• Tree species are known to differ in their vulnerability to drought impacts. The productivity of Scots pine, Douglas fir, and Sitka spruce can be heavily impacted by severe droughts. Trials of different species provenances have shown that there can be as large a variation in drought susceptibility between provenances as between species.
• Drought effects are the result of the complex interplay between climate extremes, many different components of forest ecosystems and other biotic and abiotic disturbances. All these elements will be affected by climate change in ways that cannot be confidently projected, which makes predicting the interactions between them even more difficult.
• There is medium confidence that applying dendrochronology (the study of annual growth increments, or tree rings) alongside remote sensing and drought indices could help understanding of the risk of large-scale drought impacts.

Agro-forestry is the integrated use of trees on a farm or small holding for a wide range of benefits.  The Scottish Government has set statutory targets for the reduction of GHG emissions in Scotland through the Climate Change (Scotland) Act 2009. Agroforestry in Scotland is one option that could help achieve these targets, while also supporting sustainable adaptation to a changing climate.

This report identifies the wide range of potential benefits of increasing the use of agroforestry practice in Scotland and will support further discussion towards implementation.

The Scottish Government’s ambition is to increase woodland cover in Scotland to 25% by the second half of the century. The Scottish Climate Change Plan (2017) has an ambition to increase from the current 18% to around 21% of woodland cover by 2032. This will make an important contribution to reducing Scotland’s net greenhouse gas (GHG) emissions.

However, it is important to understand the consequences of forestry activity, given that approximately two-thirds of Scotland is covered by high carbon-content organic soils of varying depths, including nearly a quarter with deep peat soils

This report examines new evidence published since the Forest Research report ‘Understanding the GHG implications of forestry on peat soils in Scotland’ (Morison et al., 2010). The review broadly confirms the findings of the 2010 report. It remains probable that moderate and high productivity forests planted on shallower peat soils with limited disturbance provide a substantial net carbon uptake over the forest cycle.

Soil carbon, or the content of carbon housed within soil, plays a significant role in the release and absorption of global greenhouse gas emissions. Changes in land use contribute to release of this carbon, and Scottish Government is interested in the potential implications of such change across several policy areas.