Abies balsamea
Abies lasiocarpa
Acer glabrum
Acer negundo
Acer pensylvanicum
Acer rubrum
Acer saccharinum
Acer saccharum
Aesculus glabra
Alder:
Thinleaf Alder (Alnus tenuifolia)
Alnus tenuifolia
Arbutus menziesii
Arctostaphylos manzanita
Ash:
Green Ash (Fraxinus pennsylvanica)
White Ash (Fraxinus americana)
Asimina triloba
Aspen:
Quaking Aspen (Populus tremuloides)
Big-Toothed Aspen (Populus grandidentata)
Baldcypress (Taxodium distichum)
Basswood:
American Basswood (Tilia americana)
Beech:
American Beech (Fagus grandifolia)
Blue Beech (Carpinus caroliniana)
Betula nigra
Betula occidentalis
Betula papyrifera
Birch:
Paper Birch (Betula papyrifera)
River Birch (Betula nigra)
Water Birch (Betula occidentalis)
Box Elder (Acer negundo)
Buckeye:
Ohio Buckeye (Aesculus glabra)
Carpinus caroliniana
Carya (Synoptic Key to Hickories) 
Carya alba
Carya glabra
Carya illinoinensis
Carya ovalis
Carya ovata
Cedar:
Eastern Red Cedar (Juniperus virginiana)
Northern White Cedar (Thuja occidentalis)
Celtis occidentalis
Cercis canadensis
Cherry:
Black Cherry (Prunus serotina)
Cornus florida
Cottonwood:
Eastern Cottonwood (Populus deltoides)
Narrowleaf Cottonwood (Populus angustifolia)
Plains Cottonwood (Populus deltoides ssp. monilifera)
Cupressus macrocarpa
Cypress:
Monterey Cypress (Cupressus macrocarpa)
Diospyros virginiana
Dogwood:
Flowering Dogwood (Cornus florida)
Douglas-Fir (Pseudotsuga menziesii)
Elm:
American Elm (Ulmus americana)
Slippery Elm (Ulmus rubra)
Eucalyptus (Eucalyptus spp.)
Fagus grandifolia
Fir:
Balsam Fir (Abies balsamea)
Douglas-Fir (Pseudotsuga menziesii)
Subalpine Fir (Abies lasiocarpa)
Fraxinus americana
Fraxinus pennsylvanica
Gleditsia triacanthos
Hackberry (Celtis occidentalis)
Hemlock:
Eastern Hemlock (Tsuga canadensis)
Hickory:
Synoptic Key to Hickories
Mockernut Hickory (Carya alba)
Pignut Hickory (Carya glabra)
Red Hickory (Carya ovalis)
Shagbark Hickory (Carya ovata)
Holly:
American Holly (Ilex opaca)
Hop Hornbeam (Ostrya virginiana)
Hornbeam (Carpinus caroliniana)
Ilex opaca
Juglans nigra
Juniper:
Rocky Mountain Juniper (Juniperus scopulorum)
Juniperus scopulorum
Juniperus virginiana
Larix laricina
Liquidambar styraciflua
Liriodendron tulipifera
Lithocarpus densiflorus
Locust:
Honey Locust (Gleditsia triacanthos)
Black Locust (Robinia pseudoacacia)
Madrone:
Pacific Madrone (Arbutus menziesii)
Magnolia:
Big-Leaf Magnolia (Magnolia macrophylla)
Manzanita (Arctostaphylos manzanita)
Maple:
Dwarf Maple (Acer rubrum)
Red Maple (Acer rubrum)
Silver Maple (Acer saccharinum)
Striped Maple (Acer pensylvanicum)
Sugar Maple (Acer saccharum)
Oak:
Black Oak (Quercus velutina)
Blackjack Oak (Quercus marilandica)
Bur Oak (Quercus macrocarpa)
Chestnut Oak (Quercus montana)
Chinkapin Oak (Quercus muehlenbergii)
Coast Live Oak (Quercus agrifolia)
Gambel Oak (Quercus gambelii)
Northern Red Oak (Quercus rubra)
Overcup Oak (Quercus lyrata)
Pagoda Oak (Quercus pagoda)
Pin Oak (Quercus palustris)
Post Oak (Quercus stellata)
Scarlet Oak (Quercus coccinea)
Shingle Oak (Quercus imbricaria)
Southern Red Oak (Quercus falcata)
Swamp White Oak (Quercus bicolor)
Tanoak / Tanbark Oak (Lithocarpus densiflorus)
White Oak (Quercus alba)
Water Oak (Quercus nigra)
Willow Oak (Quercus phellos)
Ostrya virginiana
Pawpaw (Asimina triloba)
Pecan (Carya illinoinensis)
Persimmon (Diospyros virginiana)
Picea abies
Picea engelmannii
Picea pungens
Pine:
Bishop Pine (Pinus muricata)
Colorado Pinyon Pine (Pinus edulis)
Eastern White Pine (Pinus strobus)
Jack Pine (Pinus banksiana)
Limber Pine (Pinus flexilis)
Loblolly Pine (Pinus taeda)
Lodgepole Pine (Pinus contorta)
Monterey Pine (Pinus radiata)
Ponderosa Pine (Pinus ponderosa)
Red Pine (Pinus resinosa)
Scots Pine (Pinus sylvestris)
Shortleaf Pine (Pinus echinata)
Table Mountain Pine (Pinus pungens)
Virginia Pine (Pinus virginiana)
Pinus banksiana
Pinus contorta
Pinus echinata
Pinus edulis
Pinus flexilis
Pinus muricata
Pinus ponderosa
Pinus pungens
Pinus radiata
Pinus resinosa
Pinus strobus
Pinus sylvestris
Pinus taeda
Pinus virginiana
Platanus occidentalis
Poplar (see also Cottonwoods and Aspens):
Balsam Poplar (Populus balsamifera)
"Tulip Poplar" (Liriodendron tulipifera)
White Poplar (Populus alba)
"Yellow Poplar" (Liriodendron tulipifera)
Populus alba
Populus angustifolia
Populus balsamifera
Populus deltoides
Populus deltoides ssp. monilifera
Populus grandidentata
Populus tremuloides
Prunus serotina
Pseudotsuga menziesii
Quercus agrifolia
Quercus alba
Quercus bicolor
Quercus coccinea
Quercus falcata
Quercus gambelii
Quercus imbricaria
Quercus lyrata
Quercus macrocarpa
Quercus marilandica
Quercus montana
Quercus muehlenbergii
Quercus nigra
Quercus pagoda
Quercus palustris
Quercus phellos
Quercus rubra
Quercus stellata
Quercus velutina
Redbud:
Eastern Redbud (Cercis canadensis)
Redwood (Sequoia sempervirens)
Rhododendron:
Great Rhododendron (Rhododendron maximum)
Rhododendron maximum
Robinia pseudoacacia
Salix interior
Salix lasiolepis
Salix nigra
Sassafras (Sassafras albidum)
Sequoia sempervirens
Spruce:
Blue Spruce (Picea pungens)
Engelmann Spruce (Picea engelmannii)
Norway Spruce (Picea abies)
Sweetgum (Liquidambar styraciflua)
Sycamore (Platanus occidentalis)
Tamarack
Tanoak
Taxodium distichum
Thuja occidentalis
Tilia americana
Tsuga canadensis
Tulip Tree
Ulmus americana
Ulmus rubra
Walnut:
Black Walnut (Juglans nigra)
Willow:
Arroyo Willow (Salix lasiolepis)
Black Willow (Salix nigra)
Sandbar Willow (Salix interior)
