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Research article - Peer-reviewed, 2014

Changes in ecosystem carbon stocks in a grassland ash (Fraxinus excelsior) afforestation chronosequence in Ireland

Wellock, Michael L.; Rafique, Rashad; LaPerle, Christina M.; Peichl, Matthias; Kiely, Gerard

Abstract

AimsGovernment policy in Ireland is to increase the national forest cover from the current 10% to 18% of the total land area by 2020. This represents a major land use change that is expected to impact on the national carbon (C) stocks. While the C stocks of ecosystem biomass and soils of Irish grasslands and coniferous forests have been quantified, little work has been done to assess the impact of broadleaf afforestation on C stocks.MethodsIn this study, we sampled a chronosequence of ash (Fraxinus excelsior) forests aged 12, 20, 27, 40 and 47 years on brown earth soils. A grassland site, representative of the pre-afforestation land use, was sampled as a control.Important FindingsOur results show that there was a significant decline (P < 0.05) in the carbon density of the soil (0-30 cm) following afforestation from the grassland (90.2 Mg C ha(-1)) to the 27-year-old forest (66.7 Mg C ha(-1)). Subsequently, the forest soils switched from being a C source to a C sink and began to sequester C to 71.3 Mg C ha(-1) at the 47-year-old forest. We found the amount of C stored in the above- and belowground biomass increased with age of the forest stands and offset the amount of C lost from the soil. The amount of C stored in the above-and belowground biomass increased on average by 1.83 Mg C ha(-1) year(-1). The increased storage of C in the biomass led to an increase in the total ecosystem C, from 90.2 Mg C ha(-1) at the grassland site to 162.6 Mg C ha(-1) at the 47-year-old forest. On a national scale, projected rates of ash afforestation to the year 2020 may cause a loss of 290 752 Mg C from the soil compared to 2 525 936 Mg C sequestered into the tree biomass. The effects of harvesting and reforestation may further modify the development of ecosystem C stocks over an entire ash rotation.

Keywords

ash (Fraxinus excelsior L.); chronosequence; soil; biomass; carbon; ecosystem

Published in

Journal of Plant Ecology
2014, Volume: 7, number: 5, pages: 429-438
Publisher: OXFORD UNIV PRESS

    Sustainable Development Goals

    SDG15 Life on land

    UKÄ Subject classification

    Forest Science

    Publication identifier

    DOI: https://doi.org/10.1093/jpe/rtt060

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/63119