CARBON SEQUESTRATION IN A SPANISH CHESTNUT COPPICE

Carbon balance is one of the most important in nature, since it determines the flow of organic matter, governs the balance of other bioelements (N, P, S, etc.), and controls the content of CO₂ in the atmosphere. The objective of this work was to quantify the C sequestration in a sweet chestnut forest located in the ‘Sierra de Gata’ Mountains (Central-Western Spain). This chestnut coppice is located in the South edge of the ‘Sierra de Gata’ mountains (province of Cáceres, Spain). Climatic characteristics of the area are mean temperature 15°C and mean annual-rainfall 1158 mm yr^-1 (i.e. sub-humid Mediterranean). Soils were classified as an association of haplic Umbrisols and Leptosols. The studied coppice of Castanea sativa is 25 years old (i.e. usual rotation time); the accumulation of C in the tree biomass was 58 mg C ha^-1 yr^-1; the calculated litter decomposition-constants 0.39 yr^-1; and the aboveground annual-production 5.3 mg C ha^-1 yr^-1. Accumulation of C in the Ah horizon was 143 mg C ha^-1, referred to 85 cm depth. On calculating an annual overall balance, inputs of C into this forest ecosystem are always higher than the C outputs, C sequestration being 4.6 mg C ha^-1 yr^-1.