Query: Trees from Western Canada that are not found in the Northwestern US
Domain: plants
Relevant documents:
Abies amabilis
Pinus resinosa
Acer circinatum
Cornus alternifolia
Acer glabrum
Betula neoalaskana
Acer spicatum
Larix laricina
Tilia americana
Jack pine
Picea mariana
Ostrya virginiana
Fraxinus nigra
Acer macrophyllum