The provincial power to manage Crown land did not initially extend to Manitoba, Alberta and Saskatchewan when they were created from part of the Northwest Territories, since the land was vested in the federal Crown. It was vacated on some land (the Railway Belt and the Peace River Block) by British Columbia when it entered the confederation. Title to this land was not vested in those provinces until the passage of the Natural Resources Acts in 1930. The power is not absolute, however; provincial Crown land may be regulated or expropriated for federal purposes. The administration of crown land is also subject to the rights of First Nations (since they are a relevant interest), and provincial power "is burdened by the Crown obligations toward the Aboriginal people in question". Debate exists about whether such burdens apply in the same manner in the Western provinces under the Natural Resources Acts.