Spruce vs fir: how to tell them apart

Fir tree identification by needles

Fir needles are single, flat and soft to the touch. On balsam fir, NRCan gives them 1.5 to 2.5 cm long with a rounded or notched tip, spread in two rows along the twig with the upper ones shorter. The top is shiny dark green; underneath, 10 to 12 lines of white dots form two silvery bands. Crushed, they give off a strong odor; Ohio State describes fir needles in general as citrusy when crushed. They are soft, never stiff and prickly like most spruce needles.

Two more fir clues sit at the twig tip: the buds are broadly egg-shaped, about 5 mm long and resinous, and the twigs are greenish gray and slightly hairy (NRCan). A fir needle pulled from the twig always comes away cleanly from its round base, which is the single most reliable fir tree identification test when there are no cones.

Spruce tree identification: white, black and Colorado spruce

Once the roll-and-pull test says spruce, the species usually comes from the twig, the smell and the cone.

White spruce (Picea glauca). Needles 1/3 to 3/4 inch, green to gray-green, on hairless twigs. Crush a few: Virginia Tech describes a pungent odor that some compare to cat urine, and the USDA Forest Service's Silvics of North America lists skunk spruce and cat spruce among its other names. Cones are cigar-shaped, 1 1/2 to 2 1/2 inches, with rounded scales. In the United States the Forest Service places it in Alaska, Minnesota, Wisconsin, Michigan, New York and Maine, with possible outliers in Montana, Wyoming and South Dakota; in Canada it ranges from Newfoundland and Labrador to the Yukon.

Black spruce (Picea mariana). Needles are short, 8 to 15 mm, straight, blunt-pointed and dull grayish green, and the twigs carry many short brownish hairs (NRCan's black spruce factsheet). The cones are the giveaway: open, almost round, and able to stay on the tree for up to 30 years, so an old black spruce is often crowded with gray cones near the top. In the southern part of its range it grows mostly on wet, poorly drained sites such as bogs.

Colorado blue spruce (Picea pungens). Wisconsin Extension notes its longer, very sharp needles, which make it hard to decorate as a Christmas tree. Ohio State's fact sheet names it alongside Norway spruce and white spruce, and the same peg and roll tests apply to all three.

Balsam fir and Fraser fir

Balsam fir (Abies balsamea) is the fir of the North. The Forest Service maps it from Newfoundland and Labrador west to northwestern Alberta, and in the United States from extreme northern Minnesota east through New York and central Pennsylvania into New England, with local stands in the mountains of Virginia and West Virginia. Mature trees stand 40 to 60 feet tall and 12 to 18 inches in diameter. The Forest Service gives a maximum age of about 200 years; NRCan says about 150.

In Canada, NRCan describes balsam fir as a tree of the northern forests of central and eastern Canada, and black spruce as transcontinental, extending south into the United States: these are two of the conifers Canadians meet first in the boreal forest. The Canada tree identification guide sorts them by region, with tamarack, the boreal conifer that drops its needles every autumn.

Fraser fir (Abies fraseri), native to the eastern United States according to Wisconsin Extension, is the other popular Christmas-tree fir. The Forest Service calls balsam fir closely related to Fraser fir, and the two share flat needles, upright cones and resin-blistered bark. Wisconsin Extension describes Fraser fir needles as flat, shiny dark green above and lighter below, more crowded on the twig than balsam's, with horizontal branches that give the tree a stiff look. On a tree lot, the label is usually the quickest way to tell them apart.

Douglas-fir: the look-alike that is neither

Douglas-fir (Pseudotsuga menziesii) carries "fir" in its name, which sends people to the wrong genus. Virginia Tech's Douglas-fir fact sheet gives the test in one line: its single needles "lack woody pegs or suction cups." They are 3/4 to 1 1/4 inches long, blunt-tipped and very fragrant. Two other marks settle it:

• Buds: long, sharp-pointed and red-brown, unlike a fir's round, resin-coated buds.
• Cones: 3 to 4 inches, hanging like a spruce's, with three-lobed bracts sticking out beyond the scales, which Virginia Tech compares to the back half of a mouse.

Hemlocks also have short, flat needles; they, and the pines, larches and cedars, are in the conifer identification key. For pines, whose needles come in bundles, see the pine page. If the tree has scales instead of needles, it belongs on the cedar page.

Spruce or fir in winter and from a distance

Because both keep their needles all year, spruce and fir are among the easiest trees to identify in winter; the winter tree identification guide covers the leafless broadleaves around them. From a distance, look at the top of the crown: upright fir cones, grayish brown when ripe (NRCan), stand on the uppermost branches until they break apart in early fall, while spruce cones hang down. Under the tree, whole cones mean spruce; loose scales and winged seeds mean fir. Spruces keep their needles for four to 10 years, Ohio State notes, so the woody pegs are easiest to see on older twig sections near the main stem.

If you can't reach a branch, a close photo of the needles and twig gives the best result. Tree Identifier names a tree from one photo, and its Collection includes Norway spruce, Colorado blue spruce and Douglas-fir. Tree Identifier's Tree Map keeps the location of each identified tree, which helps if you want to come back for the cones in late summer.