Estimating and valuing the carbon sequestered in softwood and hardwood trees, timber products and forest soils in Wales

Models of carbon storage in softwood and hardwood trees and forest soils an d its emission from timber products and waste are developed and integrated with data on storage benefits to yield estimates of the value of the net ca rbon flux generated by afforestation. The long-term nature of the processes under consideration and the impact of varying the discount rate are explic itly incorporated within the model. A geographical information system (GIS) is used to apply carbon sequestration models to data on tree growth and so il type distribution for a large study area (the entire country of Wales). The major findings are: (1) all three elements under analysis (carbon seque stration in livewood, release from different products and waste, and storag e or emission from soils) play a vital role in determining overall carbon f lux; (2) woodland management has a substantial impact upon carbon storage i n livewood however the choice of discount rate exerts the largest overall i nfluence upon estimated carbon flux values; (3) timber growth rates (yield class) also have a major impact upon values; (4) tree species does affect s torage values, however this is less important than the other factors listed above; (5) non-peat soils generally sequester relatively low levels of car bon. Planting upon peat soils can result in very substantial emissions of c arbon which exceed the level of storage in livewood. The GIS is used to produce valuation maps which can be readily incorporated within cost-benefit analyses regarding optimal locations for conversion of land into forestry. (C) 2000 Academic Press.