(a) gravel, sand, sandstone, rock and borrow material required for provincial tree nurseries and provincial parks;

(b) gravel, sand, sandstone, rock and borrow material required for district forestry offices;

(c) fuel wood required for provincial camp grounds; and

(d) services and supplies purchased in the course of a special investigation undertaken for the purposes of the protection of land and water and their mineral, vegetable and other components, including the flora, fauna and fish on the land or in the water.