This article, which appeared in the July 2008 issue of Sawmill & Woodlot Magazine, is part of S&W Publishing LLC’s “Tree Species” series and is not intended for reprint or republication. It is posted here with permission from Sawmill & Woodlot Magazine. To access copies of Sawmill & Woodlot’s “Tree Species” articles, visit http://sawmillmag.com/treespecies.php
EASTERN RED CEDAR (Juniperus virginiana; technically a juniper and not a cedar) is known by many different names, including aromatic cedar, Virginia juniper, and Tennessee red cedar. Historical records show that this tree would sometimes reach 120 feet in height and 4 feet in diameter with an age of 300 years. Such trees have apparently all been harvested. Today, with much smaller trees, the wood tends to be quite knotty. Pure heartwood, without the white sapwood streaks, is not always easy to find. The wood is aromatic—and smells like gerbils! Older people may remember the cedar smell in “hope chests” that young ladies used for storing linens, woolens, and other fabrics. The moth-repelling properties were highly touted, although somewhat overstated. (There is not much activity by producers in refuting this commonly held belief.) During the settlement of the United States by the colonists, cedar was prized as a fencing material due to its natural decay resistance. It was also used for buckets and shingles. In the first half of the 20th century, it was prized for making pencils until tree supplies dwindled. Today, although in limited supply, its wonderful aroma makes eastern red cedar lumber highly prized for chests and closet and wardrobe liners, as well as for pet bedding. It is also used for making curios and aromatic blocks to put with clothes in dressers and chests. The bark is quite thin and very stringy, and comes off in fibrous strips. The juniper berries, purple-blue in color, are loved by birds, and are also associated with gin making and spices for cooking. Cedar leaf oil has been used for medicine. The wood oils have been used for perfume.
PROCESSING: Suggestions and Characteristics
This is a small tree, seldom over 40 ft. tall and quite often only 20 ft. high and seldom larger than 20 in. in diameter. It is ubiquitous throughout the Middle Atlantic states, especially along fence lines where birds have deposited the seeds. It is claimed that this is the most widespread conifer in the East, growing in an area from Nova Scotia to North Dakota to Texas to Florida. Because of this particular tree’s association with cedar-apple rust disease, cedar has been intentionally eliminated from some areas, such as the Shenandoah Valley of Virginia.
DENSITY. The density of eastern red cedar averages about 32 lbs. per cubic foot at 8% MC. A board foot of dried, 3/4 in.-thick lumber will weigh no more than 2 lbs.
SAWING. The small diameter and large number of small knots make this wood of less interest to the larger mills. Small mills can profitably cut this material. As spike knots, which result when quartersawing, are not desirable (spike knots can drastically weaken lumber), it is important to produce flatsawn lumber. This means frequent turning of the log. Typically the entire log is sawn into lumber; no large cants are produced. Often 5/4 thickness is sawn, and after drying, the 5/4 is resawn into two, 1/2 in.-thick pieces. Sometimes this is done with 4/4, producing 3/8 in.-thick resawn pieces. In either case the board footage of lumber doubles. The sawdust can be saved and potentially used for pet bedding material.
DRYING. The wood dries very easily and quickly with little warp or cracking. However, if temperatures in the dryer exceed 80 F, the heat will drive off the aromatic oils, substantially reducing the aroma after the wood is dried. Shrinkage in drying is under 4%. Final moisture contents for red cedar would typically be between 7% and 10% MC.
GLUING & MACHINING. Eastern red cedar glues very well without special preparation. The wood also machines well, especially if knives are sharp and sandpaper is fresh. Rake angles can be larger than for most hardwoods. Sanding can often restore the aroma to older wood. The dust can be an irritant to some people causing dermatitis and respiratory problems.
STABILITY. Eastern red cedar is quite stable, changing 1% in size for each 6% MC change tangentially (parallel to the rings), and 1% for each 10% MC change radially (across the rings).
STRENGTH. The bending strength (MOR) averages 8,800 psi. Hardness is 900 lbs. Stiffness (MOE) averages 0.9 million psi.
COLOR & GRAIN. The sapwood is very white, while the heartwood is reddish purple to reddish brown. Streaks of sapwood in the heartwood result in a dramatic appearance; avoid using streaky material outdoors, as it may not have the best insect repellent properties. It is common to have many tight knots that add to the character as well.
PESTS & DISEASES Eastern red cedar is tormented by a variety of insect pests, although few typically cause serious damage. Among the most common of these is the bagworm—a small caterpillar that dines on cedar foliage while enclosed in a silken bag strewn with bits of foliage, twigs, and other organic debris. Local outbreaks of the bagworm or another small caterpillar called the juniper webworm can lead to complete defoliation of large trees. Extensive crown discoloration and damage can also result from feeding by leaf piercing-sucking insects, such as the juniper scale and the spruce spider mite. Additionally, a number of bark and wood-boring beetles, such as the juniper bark beetle and the blackhorned juniper borer, routinely attack the branches and bole of dying or weak- ened trees. Our featured species also serves as host for dozens of fungal pathogens, and at least one of these, Annosum root rot, is a common and widespread cause of cedar mortality. Cedars in recently harvested, thinned, or otherwise disturbed stands are especially vulnerable to this disease. Most of the other fungi, however, are typically little more than a nuisance. For example, cedar hosts several rusts from the genus Gymnosporangium, the best known of which is cedar apple rust. In order to complete its life cycle, the fungus also infects foliage and fruit of apple trees. The rust forms reddish brown galls on cedar branches, and, under humid conditions in the summer, the galls produce orange, gelatinous (and sporebearing) “horns” that can be quite numerous and conspicuous. These “cedar apples” pose no threat to the host. On the other hand, considerable damage, and at times death of young trees, is caused by Phomopsis, Kabatina and Cercospora blights, the symptoms of which are foliage yellowing or bronzing, tip dieback, and crown thinning.
MARKETS. Many contractors and remodelers are interested in obtaining small quantities of 1/2 in.- or 3/8 in.-thick lumber, dried and planed, for lining closets. Often they want the edges to be tongue and groove, although a simple lap joint should serve equally well. The more remanufacturing that can be done after drying, the easier it is to sell this wood. Experience shows that sales are often in smaller quantities and require rapid delivery. This means that a mill must carry an inventory of kiln-dried stock in order to respond quickly to sales requests. In short, success in selling will be in direct relationship to the effort put into marketing.
Gene Wenger is a Professor Emeritus at the University of Wisconsin-Madison and president of The Wood Doctor’s Rx. He can be reached at [email protected].
Eric Kruger is a professor in the Department of Forest Ecology & Management at the University of Wisconsin-Madison. He can be reached at [email protected].