Effects of Different Management Regimes for Cutover Areas on Soil Carbon Storage in Chinese Fir Plantations

Abstract

Based on data collected (through local observations) for several consecutive years, comparative analyses of Chinese fir plantations in Huitong, Hunan, were made. Results show that, before harvesting, carbon storage in forest soils in these 22-year-old plantations (0–60 cm) amounted to 160.38 t/hm2; 1 year after a 100% clear-cutting, loss of carbon storage in the soil (0–60 cm) of cutover areas was 35.00%; 2 years later, the rate was 44.65%; and, after 3 years, the rate was 43.93% compared with a control area of a standing forest. Three years after 50% thinning and 100% clear-cutting, the loss of carbon storage in the soil (0–60 cm) of cutover areas was 16.14 and 45.15%, respectively. There existed an evident difference in carbon storage in the soil (0–60 cm) of cutover areas in four kinds of management regimes, which followed the order: closed Chinese fir forests (108.20 t/hm2) > fallow lands after farming (92.68 t/hm2) > commercial forests (85.80 t/hm2) > naturally regenerated forestlands after harvesting. Carbon storage in unburnt soil (0–45 cm) reached 73.36 t/hm2, which was 15.20 t/hm2 higher than that in the soil of burnt areas. A total of 20.7% of carbon storage in the soil (0–45 cm) of burnt areas was lost 40 days after burning. Carbon storage in surface soil (0–15 cm) was higher than in the lower soil layer, which amounted to 30.04% (0–60 cm) and 53.52% (0–30 cm) of total carbon storage in the soil.