| Global climate change and how to reduce carbon emission have been one of hotspots in today's world. Forests are the most important terrestrial ecosystem in terms of sequestration and storage of carbon, playing an essential role in the global carbon cycle. As a carbon sink, plantations have been paid more and more attention as they continuously increased in many countries. The Metasequoia glyptostroboides plantation area has become bigger in the past 30 years and it would play important roles as a carbon sink in Chongming Island. But there are few data on carbon storage of M. glyptostroboides plantations, limiting the precise estimation on the carbon sink. In this study, the carbon storage of M. glyptostroboides stands at ages of 8, 15 and 30 years-old was investigated, the results were showed as follows:(1) The leaf area index (LAI) of the stands became the biggest in August, being 2.3, 2.7 and 2.5 in the three stands, respectively. The order of the LAI was 30 years>15 years>8 years-old stand. The litterfall was 1.04, 2.67, and 3.87 t·hm-2yr-1 in the three stands, respectively, and the leaf litter occupied more than 90% of total litterfal.(2) In three stands, the soil bulk density and the total potassium concentration increased firstly and then decreased with soil depth; the pH, total phosphorus concentration decreased with soil depth; the total nitrogen concentration in the 0-20 cm layer was 1.08, 1.35 and1.58 g·kg-1; the order of total phosphorus, nitrogen, potassium concentration in the same layer was 30 years > 15 years> 8 years-old stand.(3) The carbon concentration of the leaf and brance in the litterfall was 47.35%, 48.11% and 47.67% and 44.40%, 44.86% and 46.07%. The carbon concentration of the underground vegetation and forest floor (undecomposed part) was 43.6%, 40.1% and 41.7% and 42.6%, 40.3% and 38.6%. The soil carbon concentration in the 0-20cm layer was 10.28, 11.63g·kg-1 and 12.35g·kg-1. The order of the soil carbon storage in the same layer was 30 > 15> 8 years-old stand. In three stands, carbon concentration decreased with soil depth, being significantly different (p < 0.05) between two adjacent layers.(4) Total carbon storage was estimated to be 87.02, 117.69, and 160.26 t?hm2 in the three stands, respectively. Soil carbon occupied 88.9%, 75.6% and 57.6%; tree biomass carbon was 5.2%, 22.8% and 40.5%; underground vegetation carbon was 2.2%, 0.6% and 0.5%; forest floor carbon was 3.6%, 1.0% and 1.4%. Soil carbon mainly accumulated in the 0-20cm layer in the three stands. |
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