The Chipewyan were highly mobile, with the movement and dispersal of camps and hunting groups determined by the nature and availability of resources, especially caribou. In the winter and early spring camps were located at elevated points on the forest edge in areas frequented by the caribou. In the summer, when caribou were sometimes scarce, camps were located near lakes and streams containing fish. Trade with Europeans and the establishment of European trading posts undermined the traditional pattern of mobility and gradually led to permanent clustered settlements. In the twentieth century this trend has been reinforced by government relocation programs, the establishment of schools and other services, increased commerce, and limited wage labor opportunities. The traditional dwelling was a conical structure built of a framework of wooden poles covered with sewn caribou skins. As the settlement pattern became more permanent, the traditional dwellings were replaced by canvas tents and log homes, which were still common in the 1970s.