Aboveground woody biomass of natural birch woodland in Iceland-comparison of two inventories 1987-1988 and 2005-2011

Abstract

The only native tree species in Iceland forming woodland is the mountain birch. Since human settlement in the 9th century AD, natural birch woodlands have decreased from around 28% to 1.5% of the terrestrial area. In this paper we estimated and compared aboveground woody biomass stocks of two sample inventories from 1987-1988 and 2005-2011. Total above-ground woody biomass stocks in 1987-1988 and 2005-2011 were 1503 Gg (SE = 175, n= 272) and 1455 Gg (SE = 180, n= 181), respectively, for the woodland already existing in 1987-1988. The biomass estimates in 2005-2011were not significantly different from the 1987-1988 estimates in the < 2 m height class (P = 0.282) nor in the 2-4 m height class (P = 0.673). We concluded that the aboveground woody biomass of the natural birch woodland already existing in 1987-1991 had not changed between the two inventories. Additionally, we estimated an aboveground woody biomass increment of 37 Gg for the woodland expansion occurring between these two inventories.