Spruce, Fir, Hemlock
Many people use the generic term “pine tree” for any kind of evergreen, but the fact is, there are over 68 genera of evergreens. One of the more common members are spruce trees. Most spruce trees are inhabitants of cooler regions throughout the globe. Forty species of spruce trees are found throughout the world, about half of which are found in China. There are no native spruce to Frederick County, but Norway spruce, blue spruce, white spruce, and red spruce have been planted and grow in the area.
A single spruce needle connects to all sides of the twig by a peg-like projection. Most spruce cones hang downward from the stem, not upright. Spruce wood is light, but unusually strong. The strength per weight ratio of spruce makes it a very desirable wood for acoustic guitars and other string instruments. The red or Adirondack spruce is a very prized tone wood for guitars. Other prized spruce tone woods come from Norway spruce, Italian Spruce, Sitka, and Engelmann spruce. The white spruce has one of the widest distributions in North America, found all across the north from the Coast of Alaska to the Atlantic Ocean. The blue spruce, or Colorado blue spruce, is a very popular ornamental tree that is prized for its bluish color. This tree is native to the Rocky Mountain Region of the US. The tree gets it blue color from a waxy coating on its needles. Some blue spruce are subject to attack by cytospera canker, a fungal disease that kills the lower branches of trees progressively, working its way up the tree.
There are about 40 species of fir trees growing across the globe in both the northern and southern hemisphere. The balsam fir and Frasier fir are the two most important trees found in the east. Firs are slower growing, medium-sized trees that have somewhat flattened needles that tend to be bunched at the upper side of the twig. Each needle is imbedded in the twig, so when it is removed, the twig resembles a suction cup. Fir cones are attached to the upper side of the branch, and the cone breaks down when it sheds its seed, so it is unlikely that fir cones are on the ground unless the immature cone falls from the tree. Balsam fir is a tree of the north, often found in level- to low lying boggy sites, where it exists with black spruce and larch. Mature firs are used for lower grade lumber, and made into paper. The Frasier Fir is found at high elevations in the Southern Appalachian Mountains, popular as a high quality Christmas tree throughout the east.
There are two species of hemlock trees found in the east: the eastern, or Canadian hemlock, and the Carolina hemlock. The eastern hemlock is long lived, and can grow to a very large size under ideal conditions. This tree has a wide distribution, ranging from the Appalachians to the lake states, and northward into Canada. The Canadian hemlock needles are two ranked and flattened, tending to be on the upper side of the twig. The cones are rather small, at about ½ to ¾ inch long. Eastern hemlocks are a very shade tolerant tree , and they can germinate under a dense canopy and continue their expansion into the overstory, even in deep shade. Hemlocks used to be pretty common in Frederick County, but many have now succumbed to hemlock woolly adelgid and hemlock elongate scale insects. A small plantation of eastern hemlocks was identified in New Jersey that seemed to exhibit natural resistance to hemlock woolly adelgid. Seedlings were developed from this plantation and sold as “Bullet Proof” hemlocks. Some of these seedlings have been planted locally, and are being monitored to see if they are truly resistant to the adelgid. If this appears to be the case, the Bullet Proof hemlocks may offer a means of reestablishing hemlocks throughout some of its former range. The Carolina hemlock is an uncommon tree that is found at high elevations in Virginia, the Carolinas, Tennessee and Georgia. The needles project from all sides of the twig on the Carolina hemlock, not two ranked like its eastern cousin. Carolina hemlock are gaining popularity as ornamental trees.
Article by FCFCDB
Nature Note for 12/9/2018