Estimation of vegetation carbon stock in Portugal using land use/ land cover data

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

This research aimed to quantify the carbon stored over the years in vegetation throughout Continental Portugal. Carbon stock was measured for the years of 1985, 2000 and 2006. For this, the CORINE (Co-Ordination of Information on the Environment) Land Cover (CLC) database was used to estimate the spatial distribution and quantity of carbon stored by each land cover class. Carbon stock was the result of each CORINE land cover class area multiplied by its respective carbon density. Densities were derived from literature, namely Portuguese Environmental Agency tables. Results show a decrease of carbon stock for the time lapse of both 1985-2000 and 2000-2006. The year 1985 had a total carbon stock of 173.08 Mt, 2000 resulted in a total of 170.22 Mt and finally the year 2006 with 159.97 Mt. Spatial distribution of the carbon stock was also verified as well as the statistics per class. Results show that the gathering of carbon stock records is a key step in monitoring changes in carbon sequestration. By using CORINE land cover as a default database, this methodology may be used by other countries members of the CORINE program and therefore may be easily comparable in between them. In another approach, the COS LULC (Carta de Ocupação do Solo or land Use Cartography) was used to compare the impact and effect of scale on carbon stock estimation, represented here by different minimum mapping units (MMU). The COS land cover from the year 1990, with a 1 ha MMU was generalized into 3, 5, 10, 15, 20 and 25 ha as a way to gather information on the effects of scale differences. Results showed a small difference but with certain remarks regarding each study area.