Hedgerows and woodland habitats are an important feature of the Irish landscape due in part to their roles in biodiversity, agricultural management and potential carbon sequestration. Greenhouse gas (GHG)emission reductions in the land use, land-use change and forestry (LULUCF) sector are largely associated with forestry sinks. However, it is suggested that there could be a potential GHG mitigation potential (sink potential) in grazing land or cropland1 following the introduction of the Rural Environment Protection Scheme (REPS), which promoted the planting of indigenous trees and development of hedgerows.Similarly, there is evidence of encroachment of hazel scrub in grazing land in the Burren landscape due to are duction in livestock numbers. There is also evidence of alder and birch expansion on abandoned/reclaimed cutaway peat lands (Black et al.,2009b). Collectively these activities constitute an additional non-forestwoody biomass sink in the Irish landscape.
Under the European Union (EU) burden-sharing agreement, Ireland will be committed to reduce its GHG emissions by 20% below the 2005 value(DEHLG, 2010). Policies and measures to enhance GHG sinks are projected to result in a reduction of ~8%below the 2005 level. Additional measures or accountable sinks are required for the 20% target to be met for the non-emission trading sectors. Emissionsand removals (Kyoto removal units (RMUs))associated within the LULUCF sector can be used as a mitigation option under the Kyoto Protocolmechanism. Article 3.4 of the Protocol allows for theaccounting of emission removals (sinks) associated with management of croplands, grazing land and forests. Selection of these activities for the first commitment period of the protocol is voluntary, butlikely to become mandatory.
Ireland did not electcropland and grassland management for the first commitment period due to uncertainty in the magnitude of emissions or sinks in this land-useactivity and a lack of methodology to report these activities on a national basis. Under the accounting and reporting rule under Articles 7 and 8 of the KyotoProtocol, a party may elect for a land-use management activity if it is shown to be directly anthropogenic.
Clearly, the expansion of non-forest woody biomass areas, such as hedgerows, in the crop and grazing land categories meets these criteria. There has been anecdotal evidence that elements of the Irish agricultural landscape, such as hedgerows and small woodland patches, may represent a significant carbon(C) sink due to an increase in non-forest woody biomass as a direct result of the REPS. However,Ireland needs to demonstrate, via transparent inventory processes, that this ’agricultural greening’ associated with Article 3.4 activities is occurring before any potential carbon sink credit can be claimed in a compliant manner.Light Detection And Ranging (LiDAR) remote sensing technology and ground-truthing techniques could offer an ideal opportunity to utilise existing land-use policies and incentives (REPS or the proposed agri-environment scheme) to realise the potential return of investment without any added cost except for the implementation and testing of a compliant monitoring,reporting and verification (MRV) programme at are latively low input cost.