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

SLU Authors

• Peichl, Matthias

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


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