Carbon sequestration in a bamboo plantation: a case study in a Mediterranean area

Abstract

In the Mediterranean region, despite bamboo being an alien species that can seriously alter plant and animal biocoenosis, the area occupied by bamboo plantations continues to increase, especially for the purpose to sequester carbon (C). However, the C dynamics in the soil–plant system when bamboo is grown outside its native area are poorly understood. Here we investigated the C mitigation potential of the fast-growing Moso bamboo (Phyllostachys edulis) introduced in Italy for climate-change mitigation. We analyzed aboveground (AGB) and belowground (as root/shoot ratio) biomass, litter and soil organic C (SOC) at 0–15- and 15–30-cm depths in a 4-year-old bamboo plantation in comparison with the former annual cropland on which the bamboo was established. To have an idea of the maximum C stored at an ecosystem level, a natural forest adjacent the two sites was also considered. In the plantation, C accumulation as AGB was stimulated, with 14.8 ± 3.1 Mg C ha^–1 stored in 3 years; because thinning was done to remove culms from the first year, the mean sequestration rate was 4.9 Mg C ha^–1 a^–1. The sequestration rates were high but comparable to other fast-growing tree species in Italy (e.g., Pinus nigra). SOC was significantly higher in the bamboo plantation than in the cropland only at the 0–15 cm depth, but SOC stock did not differ. Possibly 4 years were not enough time for a clear increase in SOC, or the high nutrient uptake by bamboos might have depleted the soil nutrients, thus inhibiting the soil organic matter formation by bacteria. In comparison, the natural forest had significantly higher C levels in all the pools. For C dynamics at an ecosystem level, the bamboo plantation on the former annual cropland led to substantial C removal from the atmosphere (about 12 Mg C ha^–1 a^–1). However, despite the promising C sequestration rates by bamboo, its introduction should be carefully considered due to potential ecological problems caused by this species in overexploited environments such as the Mediterranean area.