Query: Trees of Western Canada, but not Flora of the Western United States
Domain: plants
Relevant documents:
Pinus resinosa
Cornus alternifolia
Betula neoalaskana
Acer spicatum
Tsuga mertensiana
Larix laricina
Tilia americana
Jack pine
Celtis occidentalis
Picea mariana
Ostrya virginiana
Fraxinus nigra