The spruce trees of North America include seven different species, all of them growing north of Mexico, mostly in cool climate locations. Spruce trees are important producers of lumber and are also useful in an ornamental capacity. The spruces all have evergreen needles, most are tall and they have a conical shape.
White spruce’s range is “transcontinental,” according to the Nearctica website, as the tree grows from Labrador to Alaska, covering most of Canada and many of the northernmost states. White spruce grows to 150 feet tall and features blue-green needles. The odor that crushed needles produce gives the tree the nickname of skunk spruce. White spruce can withstand the shade and its penchant for growing best in damp, loamy areas means it is common along lakes and rivers throughout its range. White spruce suffers from insect pests such as the spruce budworm, which can severely damage the tree if infestations occur in consecutive years.
Black spruce shares a similar range with white spruce; among coniferous species in North America, the “National Audubon Society Field Guide to Trees” says that only common juniper has a wider distribution than these two spruces. Black spruce rarely will be as tall as 100 feet, with most in the 20- to 40-foot range. Black spruce has grayish-black bark and prefers moist sites, growing in bogs and around swamps. In areas with heavy snowfall, the lower branches of black spruce will actually take root after the snow bends them to the ground. This can result in a ring of smaller trees around a larger specimen.
No spruce in the world can grow taller than the Sitka spruce, a species that exceeds 200 feet on occasion, with a diameter of 5 feet. The Sitka spruce grows along the coastal areas of the Pacific Northwest. The tree excels in damp, foggy air and resists any problems that salt spray can cause other trees. Weevils and aphids are pests that damage this tree. Sitka spruce can start to decay when it suffers an injury to its trunk. Despite its large size, the Sitka spruce produces cones that are usually only about 3 1/2 inches long.
The red spruce is a medium-sized tree, attaining an average height of 50 to 80 feet. Known as an attractive ornamental spruce, the red spruce occurs in the Northeast and into the Appalachians. The red spruce requires a cool and damp climate to thrive and this species does well in acidic soil. Red spruce shares the trait of developing shallow roots like most spruces do, meaning it is wise to plant it where it gets some buffer from the wind. While certain fungi may infect weakened and old red spruces, this spruce is quite resistant to most diseases, notes the National Forest Service website.