Topographic control on phytolith carbon sequestration in moso bamboo (Phyllostachys pubescens) ecosystems

Phytolith carbon (C) sequestration has been identified to be a relatively stable and efficacious mechanism to securely reduce atmospheric carbon dioxide (CO ₂ ) concentration. As a fast-growing and Si-accumulating plant, moso bamboo (Phyllostachys pubescens) can produce large quantities of phytolith-occluded carbon (PhytOC). In this study, we sampled the mature leaves, leaf litter and soils from moso bamboo stands located in Qingshan (30°13′N, 119°47′E; Lin'an, China) to study topographic effects on phytolith and PhytOC production in moso bamboo ecosystems. Our results showed that the phytolith contents of mature leaves and leaf litter in moso bamboo stand decreased with the slope steepness as follows: 2–5° > 5–15° > 15–35°, and showed an increasing tendency with the slope position as follows: lower slope < middle slope < upper slope. The PhytOC production flux also showed the same trend as that for phytoliths and ranged from 10.32 to 16.16 kg CO ₂ ha ^{− 1} year ^{− 1} . Our data indicate that topography, especially slope position and slope steepness, should be considered as some key factors to enhance bamboo phytolith C sequestration during future bamboo afforestation and reforestation.