I just finished reading a book about the vikings in which the situation in greenland was
also mentioned. Unfortunately it is wirtten in german...
But it seems the lack of wood on the comparably warm eastern coast took its toll on the
settlers, since most of their buildings and ships etc. were made of wood. The best source
was wood from, I think, siberia which was washed ashore.
They even found some clothing in the style of the fashion of paris, and since this was
notwashed ashore (
), they obviously maintained some connection to Europe.
As far as I remember they traded products from whale- and sealhunt in exchange for wood and other things.
Over the centuries the effects of inbreeding left the settlers quite literally crippeled, and the climate changed and became colder. Around 1350 one of their settlements was found to be abandoned and plundered by the native Inuit who had arrived a few years previously.
Two houndred years later a german merchant couldnt find any settlers anymore.
But looking at the article on wikipedia there seem to be some theories about what happened to the last settlers:
http://en.wikipedia.org/wiki/History_of_Greenland#Late_Dorset_and_Thule_cultures