Cedar is classified as a softwood. This classification is rooted in the tree’s botanical origin, which is a system based on reproduction and cellular structure, not on the wood’s physical density or actual “hardness.” The terms hardwood and softwood are therefore scientific designations that describe two distinct groups of trees.
Defining Hardwood and Softwood
The difference between hardwood and softwood lies in how the tree reproduces, which dictates the anatomy of the wood. Hardwoods come from angiosperms, flowering plants that produce seeds enclosed within a fruit or shell. Softwoods come from gymnosperms, which are non-flowering, cone-bearing plants that produce “naked” seeds.
This reproductive difference results in a distinct cellular structure. Hardwoods possess specialized water-conducting cells called vessels or pores that appear as open tubes in the wood grain. This complex structure, which also includes thick-walled fibers, typically contributes to a denser and stronger material.
Softwoods have a simpler, more uniform cellular makeup. Water transport and structural support are primarily handled by long, narrow cells called tracheids. Softwoods lack the vessels found in hardwoods, which is why they are often described as non-porous wood.
Cedar’s Scientific Classification
Applying these botanical definitions, cedar is firmly placed in the softwood category. Cedar trees are conifers, meaning they are cone-bearing and belong to the division Pinophyta, making them gymnosperms. This biological fact automatically classifies all true cedars (Cedrus species) and the many woods commonly called “cedar” (like Western Red Cedar) as softwoods.
The wood’s internal structure confirms this classification, as cedar is composed almost entirely of tracheids. These cells are responsible for both conducting water and providing mechanical strength. The absence of the vessel elements and specialized fibers found in hardwoods is the defining anatomical feature of all softwood species, including cedar.
Physical Properties That Cause Misclassification
The common confusion about cedar’s classification stems from its unique physical characteristics, which lead many to assume it must be a hardwood. The botanical labels of “hardwood” and “softwood” do not correlate with the material’s actual physical hardness or durability. Some softwoods, such as Douglas fir, are harder than some hardwoods, like balsa.
Cedar is prized for its natural resistance to decay and insect damage, a property typically associated with durable woods. This resistance comes from the presence of natural oils and organic compounds within the wood’s heartwood. These chemicals act as natural preservatives, extending its lifespan in outdoor applications like decking and siding.
Furthermore, cedar possesses a relatively low density compared to many other woods, which contributes to its excellent thermal insulating and acoustic properties. Its light weight, combined with its high dimensional stability and low shrinkage factor, makes it a popular choice for construction where durability is needed.