Patterns of Biomass, Carbon, and Soil Properties in Masson pine (Pinus massoniana Lamb) Plantations with Different Stand Ages and Management Practices

Masson pine (Pinus massoniana Lamb) has been planted extensively in different parts of China for timber production and habitat restoration. The effects of stand age and management of these plantations on biomass, carbon storage, and soil physicochemical properties are poorly understood. In this study, we investigated biomass, carbon storage, and soil physicochemical properties of Masson pine plantations. The plantations were divided into four age groups (9, 18, 28, and 48 years), and into managed (MS) and unmanaged stands (UMS) in Hubei province, Central China. Tree biomass increased with stand age. A growth model indicated that maximum tree growth occurred when the plantations were 17 years old, and the average growth rate occurred when plantations were 23 years old. Tree biomass in managed stands was 9.75% greater than that in unmanaged ones. Total biomass carbon was estimated at 27.4, 86.0, 112.7, and 142.2 Mg ha(-1), whereas soil organic carbon was 116.4, 135.0, 147.4, and 138.1 Mg ha(-1) in 9-, 18-, 28-, and 48-year-old plantations, respectively. Total carbon content was 122.6 and 106.5 Mg ha(-1), whereas soil organic carbon content was 104.9 and 115.4 Mg ha(-1) in MS and UMS, respectively. Total carbon storage in the plantations studied averaged 143.7, 220.4, 260.1, and 280.3 Mg ha(-1) in 9-,18-, 28-, and 48-year-old stands, and 227.3 and 222.4 Mg ha(-1) in MS and UMS, respectively. The results of our study provide a sound basis for estimating ecosystem carbon as it relates to forest management activity and stand age.