A young afforestation area in Iceland was a moderate sink to CO<sub>2</sub> only a decade after scarification and establishment

Abstract

Abstract. This study reports on three years (2004)(2005)(2006) of measurements of net ecosystem exchange (NEE) over a young Siberian larch plantation in Iceland established on previously grazed heathland pasture that had been scarified prior to planting. The study evaluated the variation of NEE and its component fluxes, gross primary production (GPP) and ecosystem respiration (R e ), with the aim to clarify how climatic factors controlled the site's carbon balance. The young plantation acted as a relatively strong sink for CO 2 during all of the three years, with an annual net sequestration of −102, −154, and −67 g C m −2 for 2004, 2005, and 2006, respectively. This variation was more related to variation in carbon efflux (R e ) than carbon uptake (GPP). The abiotic factors that showed the strongest correlation to R e were air temperature during the growing season and soil water potential. The GPP mostly followed the seasonal pattern in irradiance, except in 2005, when the plantation experienced severe spring frost damage that set the GPP back to zero. It was not expected that the rather slow-growing Siberian larch plantation would be such a strong sink for atmospheric CO 2 only twelve years after site preparation and afforestation.

Effects of seagulls on ecosystem respiration, soil nitrogen and vegetation cover on a pristine volcanic island, Surtsey, Iceland

“…The R e values measured in the gull colony were among the highest encountered in terrestrial ecosystems in Iceland (e.g. Óskarsson, 1998;Sigurdsson, 2001;Beckmann et al, 2004;Bjarnadottir et al, 2009) and are comparable to maximum values encountered in agricultural croplands and temperate grasslands (Falge et al, 2002) or in fertile Icelandic wetlands (Óskarsson, 1998).…”

Soil CO2 efflux in boreal pine forests in the current climate and under CO2 enrichment and air warming

“…In addition, carbon cycling in terrestrial ecosystems will be affected by the changing variability of climate (Medvigy et al 2010). Already studies from recent years and decades have suggested that annual carbon budgets of boreal forest ecosystems can be notably influenced by early thaw in spring or warmer than usual autumns (Goulden et al 1998;Piao et al 2008;Bjarnadottir et al 2009), the latter through an increase in ecosystem respiration. Longer-term or delayed effects of these variations are not clear yet, such as the effects on the level of soil CO2 efflux in the following years (e.g.…”

Croissance des stocks de carbone dix ans après boisement de terrains dénudés boréaux /

“…Egalement, une jeune plantation de mélèze sibérien (Larix sibirica) établie en Islande sur des landes en pâturage s'est avérée être un puits modéré de C 12 ans après boisement, avec une séquestration annuelle de 1,02 t C ha" 1 an" 1 (Bjarnadottir et al 2009). Il ne faut cependant pas oublier que le sol minéral n'est pas inclus dans le présent projet.…”