返回Google圖書搜尋

Soil Organic Carbon Changes in the UK Forest Soils

出版	Aberdeen University, 2019
URL	http://books.google.com.hk/books?id=u8920AEACAAJ&hl=&source=gbs_api

註釋Forest soils contain large amounts of carbon, which can be lost through forest operations or changing environmental conditions. As forests are perennial with infrequent disturbance, soil organic carbon (SOC) accumulation differs from highly disturbed land uses, with significant accumulation occurring in deeper soil horizons (subsoil). This thesis investigated changes in SOC in both topsoil and subsoil under the main native broadleaved and coniferous species in the UK, oak and Scots pine. The overall results showed that prolonging forest rotations could allow more carbon (C) to be sequestered in soils. In Scots pine (Chapter 3), increasing rotation age would allow greater accumulation of the top F and H horizons, while in oak stands (Chapter 2), the most pronounced changes would be in the mineral subsoil horizons. In the oak forest, we demonstrated importance of sampling subsoil horizons (Chapter 2). Including subsoil measurements showed that young forest subsoil had similar amounts of SOC as ancient forests. Long-term RothC simulations of pine forests (Chapter 3) suggested that the lowest soil C stocks occur, not immediately after harvesting, but closer to the middle of the rotation. This shows the importance of including 40 to 50 year old stands in sampling campaigns to capture the magnitude of these losses. The simulations suggested that converting current grassland sites to forest would allow accumulation of similar amounts of SOC as in ancient forest sites. Model SOC pools were compared to measurable fractions for the 220 year old oak stands. Discrepancy between measured fractions and simulated pools (Chapter 4) suggested a significant difference in soil processes in the topsoil and subsoil. Current modelling approaches might not be sufficient to represent factors that control SOC dynamics with depth.