Tips: Select a twig that seems typical of the tree. Try to obtain a twig with reproductive structures (fruits, cones) because you may need to observe them to identify your tree. This key is for conifers (trees which have leaves that look like needles or tiny overlapping scales, are frequently evergreen, lack flowers, usually bear woody or leathery cones, and produce seeds). To use the key, read both descriptions in a couplet (for instance, 1a and 1b). Decide which best describes your sample, and move on to the next couplet indicated. Should you reach a dead-end, use the numbers in parentheses to backtrack until you reach a couplet that you feel unsure about, and try following the other path. Some tree genera are found more than once in the key because they occur with different forms. Only trees which are native to the United States are included in this key.

Trees with needles or overlapping scales:

STEP	FROM	FEATURES	GENUS
1a		Trees with needles. . . . . . . . . go to 2
1b		Trees with at least some tiny overlapping scales. . . . . . . . . . go to 13
2a	1a	Trees with fleshy, berry-like fruits. . . . . . . . . . go to 3
2b	1a	Trees with woody cones. . . . . . . . . . go to 5
3a	2a	Each bright red fruit partially covers a black seed	TAXUS (Yew)
3b	2a	Each fruit totally encloses the seed. . . . . . . . . . go to 4
4a	3b	Oval green-purple fruits with a diameter of approximately 25 mm	TORREYA
4b	3b	Globe-like blue-black fruits with a diameter of approximately 10 mm	JUNIPERUS (Juniper)
5a	2b	Groups of needles are attached to the twigs in clusters. . . . . . . . . . go to 6
5b	2b	Single needles are attached to the twigs. . . . . . . . . .go to 7
6a	5a	Clusters of 2 - 5 needles	PINUS (Pine)
6b	5a	Clusters of 12 - 50 soft needles	LARIX (Larch)
7a	5b	Cones stand up from the upper side of the twig	ABIES (Fir)
7b	5b	Cones hang down from the lower side or end of the twig. . . . . . . . . .go to 8
8a	7b	Cones have long, pointy bracts extending beyond scales	PSEUDOTSUGA (Douglas fir)
8b	7b	Cones don’t have long, pointy bracts or scales. . . . . . . . . .go to 9
9a	8b	Each needle is tucked into a papery sheath	PINUS (Singleleaf pinyon)
9b	8b	Needles are not tucked into papery sheaths. . . . . . . . . . go to 10
10a	9b	Cones attached along the length of the twig, trees often found in swamps, with root "knees"	TAXODIUM (Baldcypress)
10b	9b	Cones hang at the ends of twigs, without root "knees". . . . . . . . . . go to 11
11a	10b	Needles attached to twigs by little woody projections. . . . . . . . . . go to 12
11b	10b	Needles attached directly to stems without woody projections	SEQUOIA (Coastal redwood)
12a	11a	Needles are four-sided and stiff with sharp tips	PICEA (Spruce)
12b	11a	Needles are flat and flexible with blunt tips	TSUGA (Hemlock)
13a	1b	Trees with fleshy, berry-like fruits	JUNIPERUS (Juniper)
13b	1b	Trees with woody or leathery cones. . . . . . . . .go to 14
14a	13b	Alternated leaf scales, cones 40mm - 80 mm long with numerous, spirally arranged scales	SEQUIOADENDRON (Giant Sequoia)
14b	13b	Leaf scales opposite or whorled, cones 40 mm long with only a few opposite scales. . . . . . . . . . go to 15
15a	14b	Globe-shaped cones. . . . . . . . . .go to 16
15b	14b	Cones are longer than they are wide. . . . . . . . . .go to 17
16a	15a	Twigs form flattened cones 13 mm in diameter with 2 - 5 seeds per cone scale	CHAMAECYPARIS (False Cypress)
16b	15a	Twigs do not form flattened "sprays", cones 13 mm - 40 mm in diameter with > 5 seeds per cone scale	CUPRESSUS (Cypress)
17a	15b	Leaf scales are mostly long, narrow and pointed, seed-bearing cones are urn-ashaped with rigid scales	CALOCEDRUS (Incense cedars)
17b	15b	Leaf scales are mostly short and broad with blunt tips, seed-bearing cones are oval with flexible scales	THUJA (Arborvitae)