The maximum decrease in forest fraction is found in North America (up to 0.35 decrease, Fig.  17 a, b), where it results in a 12% increase in the surface albedo in September (Fig.  13 b).

In Scandinavia and northern Eurasia, the reduction in forest fraction (Fig.  17 a) is smaller and reaches locally 0.15–0.20, leading to a 5% rise of the surface albedo here in September.

Most of the reduction (about two-thirds) in forest fraction takes place after 6 ka BP (Fig.  17 b)..

The model appears to somewhat underestimate the southward retreat of the tree line seen in the data, as the simulated reduction in forest fraction (Fig.  17 ) does not exceed 0.15 in northern Eurasia (i.e.

the areas where we found a 0.35 reduction in forest fraction (Fig.  17 a) and a 12% rise in surface albedo in spring (Fig.  13 d).