I found this on wikipedia... I think it gives a good explanation.

Within Canada, Crown Land is a designated area belonging to the Crown, the equivalent of an entailed estate that passes with the monarchy and cannot not be alienated from it; thus, per constitutional convention, these lands cannot be unliaterally sold by the monarch, instead passing on to the next king or queen unless the sovereign is advised otherwise by the ministers of the Crown. Though the Canadian monarch owns all Crown Land in the country, paralleling the "division" of the Crown amongst the federal and provincial governments, Crown Land is similarly divied so that some lands within the province are administered by the provincial Crown, whereas others are under the federal Crown. About 89% of Canada's land area (8,886,356 km²) is Crown Land, which may either be federal (41%) or provincial (48%); the remaining 11% is privately-owned.^[3] Most federal Crown land is in the Canadian territories (Northwest Territories, Nunavut and Yukon), and is administered on behalf of Indian and Northern Affairs Canada; only 4% of land in the provinces is federally-controlled, largely in the form of National Parks, Indian reserves, or Canadian Forces bases. In contrast, provinces hold much of their territory as provincial Crown Land, which may be held as Provincial Parks or wilderness.

Crown Land provides the country and the provinces with the majority of their profits from natural resources, largely but not exclusively provincial, rented for logging and mineral exploration rights; revenues flow to the relevant government and may constitute a major income stream, such as in Alberta. Crown land may also be rented by individuals wishing to build homes or cottages.