Kathi Mirto excelled at writing and natural sciences as a classroom teacher. Today, she combines her research, knowledge, and photography!
This essay features 4 common spruce trees of Michigan. They include the Norway Spruce, White Spruce, Black Spruce, and Blue Spruce (in that order). Michigan shares many of these species with the Central and Northeastern regions of the United States and Canada.
Norway Spruce (Picea, abies)
Norway Spruce Location:
Native to central and northern Europe, including Norway, bearing the name, the Norway Spruce has become naturalized from Michigan to Connecticut in the United States and has been planted for centuries as far west as the Pacific Coast and Canada becoming perhaps the most common spruce, rivaled only by the Colorado Blue Spruce.
As a shade-tolerant species, the Norway Spruce is an adaptable competitor. It forms a lower canopy layer beneath taller trees and, eventually, outgrows them. It adapts well to a variety of harsh soil conditions including clay, rocky and dry soils, but will quickly die in wet soils. Once it is established, it can thrive under seasonal drought and tolerates city pollution.
Throughout Michigan and many other locations, the Norway Spruce is planted as an ornamental tree in both urban and rural environments possibly as a windbreak or snowbreak; and occasionally in pure stands for future lumber harvest in forests.
Norway Spruce Size and Shape
- Moderately fast growth rate, large-sized tree, reaches 65 to 100 feet (20 to 30 meters) in height and 25 to 30 foot (7.5 to 9 meter) spread at maturity. Michigan Big Tree: 82 feet (25 meters) tall, Oakland County.
- The Norway Spruce has a strong central leader with a narrow, spire-top crown and overall pyramidal shape; branches may or may not persist almost to the ground.
A distinctive trait of Norway Spruce is drooping, up-turned branches with long dangling branchlets, making it easily identifiable from a reasonable distance.
Norway Spruce Needles
Norway Spruce needles are fairly short, measuring about .5 to 1.5 inches (1.3 cm to 3.8 cm), but comparatively, the needles of Norway Spruce are the longest among the spruce family. They point forward and spiral around the twig. Needles are typically dark green, shiny, and sharp, but they are easier to grasp than the more prickly Colorado Blue Spruce, whose needles radiate more outwardly from the twig and are less flexible.
Norway Spruce needles are attached individually to orange/brown stems with a peg-like projection, visible to only the most discerning eye; one may even need a magnifying glass to see them.
Spruce Needles vs. Fir Needles
As with all spruce varieties, if you pluck a needle, you can roll it between your fingers because they have four distinct sides. This distinguishes them from fir tree needles which look much the same at first glance, and are attached to their stems singly as well, but they are flat and do not roll easily between your fingers. Also, fir needles are not attached with the peg-like projection as with all spruces (shown in the photo above).
Norway Spruce Male Pollen Cones
Norway Spruce male pollen cones release their flurry of crimson-yellow, tiny pollen scales by wind or animal disturbance in order to fertilize the more sturdy female seed cones, thereafter disintegrating (monoecious -- meaning both male and female on the same plant). In April and May, I've observed thousands of these red-yellow cones decorate a tree fantastically, like berries on a holly bush!
Early spring, female seed cones of the Norway Spruce are more erect and bright red or pink. After being fertilized by the male pollen cones, the seed cones become green and hang downward; and not until autumn, do they transform into the more recognizable reddish-brown woody cones with thin scales.
Norway Spruce Seed Cones
Norway Spruce seed cones are the largest among the spruces measuring between 4 to 7 inches (10 to 18 cm) long. They are cylindrical in shape, orangish-brown in color, and fall from the tree autumn of the second year. The seed cones are female and sturdy while the pollen cones are male and disintegrate after they fertilize the female cones (monoecious). As with all spruce varieties, the seed cones grow downward pointed toward the ground situated from the treetop branches.
Spruce Seed Cones vs. Fir Seed Cones
One of the easiest ways to tell these two species apart is by observing how their seed cones grow on the tree. Fir seed cones grow erect from their treetop branches pointed towards the sky, while spruce seed cones do the opposite as described above. Also, fir seed cones disintegrate before dropping to the ground.
Upon maturity in autumn, the Norway Spruce seed cones open up their scales to release winged seeds tucked inside; the part of the cone squirrels love to feast upon! Note: Most spruce trees have very similar winged seeds that vary only slightly, particularly by size.
Norway Spruce bark has a distinct, thin, scaly pattern that reminds me of puzzle pieces, making it quite recognizable. The color of the bark can vary from reddish tones to grayish brown.
White Spruce (Picea, glauca)
White Spruce Location
The White Spruce is a popular tree native to central and northern Michigan and scattered locations of several other northern US states and much of Canada. The White Spruce has been heavily planted throughout the state and much of the United States and Canada as an ornamental and as one of the most popular Christmas trees. It prefers drier upland forests of moist, cool climates on shallow, rocky sites, but is adaptable to clay and poorer soils. It is also well adapted to freezing conditions; is able to establish in the shade of other species on moist or wet sites, gradually able to grow into forest overstory. I've noticed in my area of Southwestern Michigan, it is often planted as a windbreak between farm pastures.
White Spruce Size and Shape
- The White Spruce tree is slow growing, long-lived, medium-sized to large tree from 60 to 100 feet (18 to 30 meters) in height with approximately a 20 foot (6 meter) spread. Michigan Big Tree: 101 feet (31 meters) tall, Luce County.
- White Spruce is typically lush, densely foliated and pyramidal with a broad spread towards the base. Branches grow upright towards the crown, especially on younger trees; the many branches grow from the trunk in a random pattern. The tree typically retains foliage on the lower branches.
White Spruce Needles
White Spruce needles measure from 1/2 to 3/4 inches (1.3 to 2 cm). White spruce needles are four square and easily roll between your fingers, they are bluish-green to dark green in color, dull, sharp, and point somewhat forward towards the tip of the branch, about 60 degrees. Their common name refers to the waxy layer on young needles.
White spruce is also known as Canadian spruce and also skunk spruce or cat spruce due to the pungent smell of the needles.
White Spruce needles are attached singly to the twig with a peg-like projection and wrap around the entire stem. The stems and twigs are yellow-tan to light gray and are not as reddish as the Norway Spruce.
White Spruce Male Pollen Cones
White Spruce male pollen cones are scattered throughout the tree canopy serving as a source of pollen by the wind or animal disturbance for the female seed cones, disintegrating sometime thereafter. As with the majority of conifers, the White Spruce tree is monoecious with both male and female cones. The above photo of the purplish male pollen cones was taken in April. The cones were spread abundantly throughout the entire tree, looking more like flourishing berries rather than cones.
White Spruce Seed Cones
White Spruce seed cones (female) are small measuring about 1 to 2 inches (2.5 to 5 cm) in length with a cylindrical oblong shape; are slightly firm. Color remains medium green throughout much of the summer, turning light brown to reddish-brown in autumn and winter when they release their seeds. The scales have straight edges. The cones grow from branches pointed toward the ground covering the upper third portion of the tree, as with all the spruces. They fall off the tree the first year.
Seed cones of the White Spruce tree are much smaller than some of their cousin species as demonstrated in the photo above. The photo also demonstrates the varying sizes of seed cones from identical species.
White Spruce bark is somewhat flaky and thin with irregular patterns. The bark is typically gray to brown and becomes more scaly upon maturity. Bark is often unseen as the dense foliage and branches persist close to the ground.
Black Spruce (Picea mariana)
Black Spruce Location
The Black Spruce tree occurs naturally in the northeastern United States, and three midwestern states of Minnesota, Wisconsin, and Michigan, extending from the northern range of North America to Alaska spreading wide across Canada reaching north all the way to the very limit of tree growth. (See map for Michigan location by county). Black Spruce is found in the low country restricted to bogs on the southern end of its range. Northward, these spruce trees can be found on the edges of wetlands, dune ridges or gravelly shores. Due to their preference for damp conditions, they are also known as Swamp Spruce or Bog Spruce. The species scientific name refers to the US state of Maryland.
Black Spruce Size and Shape
- Small to medium-sized tree with slow growth rate, reaches up to 60 feet (18 meters) high in ideal condition with a 20 to 30 foot (6 to 9 meter) spread. Michigan Big Tree: 65 feet (20 meters) tall, Isabella County.
- The Black Spruce trunk is slender, straight, and slightly tapered. In closed stands, the tree self-prunes of lower branches, has a narrow irregular, conical, spire-like crown of short slender branches. The top crown can sometimes be club-shaped. Branches tend to droop turning up at the tips.
Black Spruce Needles
Black Spruce needles are the shortest and most blunt among the spruces measuring from 1/4 to 5/8 inches ( 7 to 19 cm). Needles have a slight curve tending to grow from the stem at a forward angle. They exhibit the typical spruce, four-square shape making them easy to roll between your fingers. They are blue-green and slightly darker than other spruces bearing the name sake; needles persist on the tree 7 - 10 years.
The Black Spruce needle attachment is no different from other spruce forms growing singly from the stem using a peg-like projection. Differentiating them from other species, though, are the presence of tiny hairs on the stems between needles of new growth that tend to rub off by winter, but are difficult to see with the naked eye.
Black Spruce Seed Cones
Black Spruce seed cones are the smallest of the spruces measuring approximately 5/8 to 1.25 inches (1.6 to 3 cm) with an overall rounded to egg shape. At maturity in autumn of the first year, they become darker brown than other spruce species with fan-shaped close-fitting scales exhibiting uneven slightly fringed edges. The cones spread along the top portion of the tree persisting on branches for many years, opening intermittently during drying and releasing of seeds for 1-2 years.
Black Spruce bark is thin, scaly, grayish brown, separating into thin ragged scales.
Blue Spruce (Picea pungens)
Blue Spruce Location
The Blue Spruce tree is a native species scattered throughout North America, but is not native to Michigan (see USDA Plant Database Map). But the tree has been widely planted outside of its natural range, including Michigan, for its beauty, particularly the blue-green needles, making it a favorite among Michiganders, (trees in the Rocky Mountains vary greatly in foliage color). The Blue Spruce grows well on almost any upland soil, is drought resistant and shade tolerant. It also is known as Colorado Blue Spruce or Green Spruce, as there are green needle forms.
Blue Spruce Size and Shape
- Medium-sized tree with medium to slow growth rate reaching up to 75 feet (23 meters) in the wild, but rarely higher than 50 feet (15 meters) in city landscapes with a 10 to 20 foot (3 to 6 meter) spread.
- The Blue Spruce trunk is straight; crown is pyramidal with dense foliage; branches reach to the ground making the tree an excellent wind break, snowbreak or privacy barrier. Older branches are often downswept in large trees; branches grow in layered arrangement around trunk.
Blue Spruce Needles
Blue Spruce needles measure approximately 1 inch (2.5 cm) long, are dull, sharp and radiate outwards in all directions rather than pointing forward from the stem, making them problematic to handle. New growth is waxy and gray to bluish-green in color with conspicuous stripes, but there are green forms called Green Spruce, dependent on how much wax forms on the needle surface.
Blue Spruce needles grow singly from the stem via a peg-like projection as with all spruce trees, and spiral around the reddish-brown stem.
Early to mid spring pollen cones (male) of Blue Spruce are conspicuous, shaped oblong with narrow ends, colored pinkish-red spreading throughout the tree crown serving as the pollinator for the seed cones (female), disintegrating sometime thereafter. Tree is monoecious, meaning with both male and female producers.
By late-May to mid-June, the male pollen cones on all spruce trees turn brown and begin to disintegrate. Look closely at the needles in the photo above and you will notice tiny brown flakes caused by the male pollen cones beginning the process to pollenate to the female seed-cones as they fall apart.
Blue Spruce Seed Cones
Blue Spruce seed cones are oblong and pale brown reaching up to 4 inches (10 cm) long ripening in autumn of first season; they are located on the topmost branches of the crown. Compared to other spruce cones, the scales are thin and papery with raggedy edges. White sap drips are often seen on them, as with many other spruce tree cones.
Black Spruce bark is thin and smooth on young trees. Older trees form thin, purplish to grayish-brown, loosely attached scales which are coarsely flaky; some flakes are ash gray. The bark is usually unseen, as the tree typically branches to the ground throughout its life.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Kathi Mirto