The terms “hardwood” and “softwood” often cause confusion because they suggest a distinction based on physical density or feel. Many assume durable lumber comes from hardwoods, while lighter woods are softwoods. The actual classification is based not on density, but on the tree’s botanical characteristics. This scientific basis determines where a species like cedar fits into wood categories.
Cedar’s Classification as Softwood
Cedar is classified as a softwood, regardless of the density or durability found in some varieties. Species like Western Red Cedar and Eastern Red Cedar are derived from coniferous trees that bear cones and typically have needle-like foliage. Their botanical origin places them firmly within the softwood category. This classification holds true even though certain cedar varieties are valued for their strength and resistance to decay, qualities often associated with hardwoods.
The Botanical Basis of Wood Classification
The scientific differentiation between hardwoods and softwoods rests entirely on how the parent tree reproduces. Hardwoods come from angiosperms, which are flowering plants that enclose their seeds within a protective vessel, such as a fruit or nut. Most temperate angiosperms are deciduous, meaning they shed their leaves seasonally. Softwoods, by contrast, are sourced from gymnosperms, which are plants that produce “naked” seeds, typically found on the scales of cones.
This reproductive difference results in distinct cellular structures visible under a microscope. Hardwoods have a more complex structure that includes vessel elements, which appear as pores on the wood’s cross-section and function primarily for water transport. The bulk of the wood is composed of thick-walled fibers, which provide mechanical support. Softwoods possess a simpler, more uniform cellular architecture, composed predominantly of long, thin cells called tracheids. These tracheids perform the dual function of water conduction and structural support.
Practical Implications of Softwood Properties
Cedar’s classification as a softwood is responsible for several of its desirable material properties. It is considered one of the lightest commercial softwoods, with Western Red Cedar averaging around 21 pounds per cubic foot (oven-dry density). This low density, combined with a straight grain and uniform texture, makes it easy to cut, saw, and nail with common tools. The wood’s light weight also contributes to its high thermal insulating value, as air-filled cell cavities trap heat effectively.
Despite its low density, cedar exhibits high dimensional stability, meaning it resists warping, twisting, and shrinking when exposed to moisture changes. Its longevity in exterior applications comes from natural chemical compounds called thujaplicins, which are extractives present in the heartwood. These natural oils and phenols act as preservatives, lending the wood resistance to decay, mold, and insect damage. This combination of light weight, workability, and natural durability makes cedar a preferred material for outdoor applications like siding, decking, and fencing, as well as aromatic storage chests.