Greenland was colonized by Norsemen beginning in the 9th century. One of the main resources the Norse relied on was timber, which they used to build their ships, homes, and other structures. However, Greenland is largely treeless, and the Norse had to rely on imported timber to meet their needs. As the climate of Greenland cooled in the 14th and 15th centuries, the sea ice made it more difficult for the Norse to import timber, and the Norse settlements in Greenland eventually declined and were eventually abandoned.