"Figure 6: Carbon levels in all semi-natural habitats have increased between 1978 and 1998, but fell back for most for 2007","" "Level of carbon in soils, Great Britain, 1978, 1998 and 2007","" "","" "Notes","" "Unit","Carbon concentration (g C kg−1)" "","" "","Bracken","Dwarf shrub heath","Fen, marsh and swamp","Bog","Broadleaf, mixed and yew woodland","Acid grassland","Neutral Grassland" "1978","155.2","305.3","231.7","411.8","62.4","235.1","67.1" "1998","154.7","298.7","252.8","449.9","102.2","256.7","70.1" "2007","195.9","284.9","228.6","432.9","88.7","228.5","68.0"