There are firs and spruces on the mountains, characteristic of the Boreal zone; pines characteristic of the Transition zone; pinon juniper, greasewood and the universally conspicuous sage-brush, characteristic of the Upper Sonoran zone.
Most of the pine that formerly grew on the Archean at the northern fringe of the settlements has been cut, but the lumberman is still advancing northwards and approaching the northern limit of the famous Canadian white pine forests, beyond which spruces, tamarack (larch) and poplar are the prevalent trees.
From Labrador it ranges to the southern shores of Hudson's Bay and to those of the Great Bear Lake, and to the valley of the Yukon and the coast of Alaska, forming with the aspen, the larch, the balsam poplar, the banksian pine, the black and white spruces and the balsam fir, the great subarctic transcontinental forest; and southward it ranges through all the forest region of the Dominion of Canada and the northern states."
On the higher elevations the trees are mostly white pine, yellow pine and hemlock, but in the valleys and lower levels are oaks, hickories, maples, elms, birches, locusts, willows, spruces, gums, buckeyes, the chestnut, black walnut, butternut, cedar, ash, linden, poplar, buttonwood, hornbeam, holly, catalpa, magnolia, tulip-tree, Kentucky coffee-tree, sassafras, wild cherry, pawpaw, crab-apple and other species.
Picea Ajanensis - The finest of the Japanese Spruces, distinguished from all others by the bluish silver tint of the young branches on the undersides, but which are upturned so that the whole tree has a silvery appearance.
