For Mr. and Mrs. Anybody out there, the difference in cedar species is probably not one of their more vital concerns, but in talking to literally thousands of callers through the years about log siding, its clear most people think cedar is cedar. To help dispel that notion and clarify what advantages one type of cedar has over another, the following is offered.
All the cedars are classified as softwoods; all are durable and have a pleasant fragrance, but that is where the similarity ends. The wood from the various cedars differ from each other in color, density (insulating value), hardness of the wood, weight, strength, lengths manufactured and grades of lumber available.
Due to cedar’s natural resistance to decay and insects, it has long been the wood of choice for outdoor applications. To illustrate a point, totem poles, carved from Western Red Cedar; some standing after a thousand years, would have become part of the forest floor by this time had the Indians used, say, hemlock or pine.
Cedar is graded for appearance rather than strength and is not normally used for rafters, joists, beams or other structural components. Appearance grades range from the clears down through the various knotty classifications. Most cedar is used for siding. Other common uses are porch decking, railings, outdoor furniture, fencing material or anywhere the wood must withstand the ravages of time and the elements.
There are several species of cedar in North America but let’s eliminate the cedar shrub varieties and cedar species that don’t grow large enough to produce useable lumber. Two species called Eastern Red Cedar and Southern Red Cedar are actually juniper. They are small, “scrubby” trees, the larger of which can be cut into short boards that are used for “cedar” chests, bird houses and closet lining. Another species, Atlantic White Cedar (Chamaecyparis Thyoides), grows in a small area along the eastern seaboard. Although the larger trees might produce lumber, sufficient quantities are not available for commercial distribution.
This leaves five species of cedar with trees large and tall enough to cut into longer, graded lumber: Western Red Cedar, Incense Cedar, Port Orford Cedar and Yellow Cedar; all from the Western states, and Northern White Cedar in the Northeast. We are down to four if we eliminate Yellow Cedar (Chamaecyparis Nootkatensis) sometimes called Alaska Cedar, and is found in Alaska and northern B.C. but not distributed widely in the lower 48.
Western Red Cedar (Thuja Plicata) commonly called just Red Cedar provides the vast bulk of cedar sold, and is the standard to which all the others are measured. It is in high demand for its durability, decay resistance and dimensional stability, and due to its porous cell structure, is light in weight and makes the best insulator of all the cedars. Red is somewhat of a misnomer as the wood ranges from a light cream color to warm shades of tan and brown. WRC is the most prolific of all the cedars and grows west of the Cascade Mountains in Northern California, Oregon, Washington and British Columbia. A variety of WRC, sometimes called Inland Cedar, grows east of the mountains, and due to the drier climate, doesn’t reach the size of cedar found in the lush, rain drenched coastal forests. Old growth WRC trees are commonly six feet in diameter at the stump and can be 180 feet tall. In dense stands, the first limb may be a hundred feet off the ground. These giants yield long, clear, blemish free runs of the finest cedar lumber available anywhere, and is shipped world wide. Due to the large volume harvested, it is the species most likely to be found in your local lumber yard. The wide choice of grades, as well as the longer lengths available make WRC the most utilitarian of all the cedars. And let’s not forget shakes and shingles which are milled from – you guessed it – Western Red Cedar.
Incense Cedar (Calocedrus Decurrens) is found in Western Oregon and parts of Northern California. Although it doesn’t grow to the size of WRC, it yields quality, well graded, longer lumber. The wood is a little heavier and less porous than WRC so it lacks some of the insulating value. It has a light pine color which is a desirable feature for many. The wood is a little harder than WRC and works well for decking, railings or lawn furniture, for example where a more “scuff free” surface is needed. Due to the smaller average tree size of Incense Cedar, it doesn’t yield as many clear grades as the Western Red, but the knotty “appearance” grade lumber not only has an attractive look but is less expensive. Because of the limited growing area, Incense Cedar is not as widely available as WRC.
Port Orford Cedar (Chamaecyparis Lawsoniana) is in a class by itself. It grows only between Coos Bay, Oregon and Crescent City, California and inland from the ocean about fifty miles. The old growth trees (what few are left) rival WRC in girth and height. PO cedar has a uniform light cream color and is the strongest of all the cedars; so strong in fact that it can be used for some structural applications. The wood is exceptionally straight grained and short blocks (bolts) of old growth PO are used for the manufacture of arrow shafts. In the days when fishing vessels and other work boats were made of wood, the choice of material for hull planking was PO Cedar because of the durability and strength of the long, clear, wide lumber available at the time. Supplying the high demand from the small growing area leaves little available for the market today, especially in the clear grades. Knotty and appearance grade Port Orford lumber is sold in a few retail outlets, mostly in the west.
Northern White Cedar (Thuja Occidentalis) is found in the lake states, southeastern Canada, the New England states and Maine. This species is also known as Eastern White Cedar, but mostly is just referred to as White Cedar. Locally it has been called American Red Cedar and Swamp Cedar. A typical White Cedar tree is 50 feet tall and two feet on the stump but can reach a height of 80 feet. Saw logs generally have a low yield of top grade lumber because they are often knotty, crooked or hollow. Also, longer lumber milled from White Cedar is at a premium due to the smaller size of the logs. Like all cedar, the wood is stable and decay resistant. Unlike the Western Cedars, which have a multitude of appearance and structural grades, White Cedar is usually graded only on a #1, #2, or #3 basis.
So, armed with the forgoing info, you can tell the salesman at the lumber yard that you’re not interested in the Chamaecyparis Nootkatensis, but want to look at the Calocedrus Decurrens.