Tree line expansion?

A bit of late night journal reading led me to an article about tree line expansion due to climate change. The idea that areas currently covered in ice could become suitable environments for new trees and shrubs to grow in the near future is a positive impact of climate change! New trees = increased uptake of CO2!

The study was taken in Sweden near the tree line which marks the boundaries of the Arctic. The image on the left shows the shrub colonisation of the area in 1977 (top) compared with 2009 (bottom). As temperatures have increased here, we can see that increased amount of vegetation can grow here. Research has found that although models predict this expansion could happen along the entire Arctic boundary, some areas are showing no new vegetation despite ideal conditions...

However, surely this northward expansion of vegetation is only a good thing?! Except of course the decreased albedo due to ice melt...which I personally think can be solved by everyone painting their roofs white?!

References:

Rundqvist et al (2011), 'Tree and shrub expansion over the past 34 years at the tree-line near Abisko, Sweden', Journal of the human environment, 40, 683 - 692.