Diverse design projects often demand different types of timber. An awareness of the distinctions between various species can help to determine material selections that will best suit certain design needs. While it is well-understood that wood is often classified into two categories—hardwood and softwood—the driving differences between these two classifications are commonly oversimplified. The terms hardwood and softwood are often used in design, architecture, and construction, and it would make sense to believe this is due to the characteristics of each. However, the disparities between these two types of wood aren’t simply in their name. While hardwood is often more dense than softwood, the ways in which trees within each category reproduce is what gives them their distinct designations.
Overview and Reproduction Processes
Hardwoods come from angiosperms trees, meaning that they produce seeds within a protective covering, such as fruit or nuts. The word angiosperm comes from the Greek words angeion—meaning case or casing—and sperma, which means seed. The reproduction process begins when the tree flowers. When successfully pollinated, the flower becomes an enclosed seed that will eventually fall to the ground or be eaten and discarded. Common examples of hardwoods include alder, balsa, beech, hickory, mahogany, maple, oak, teak, and walnut.
In comparison, softwoods are gymnosperms, a word that translates to “naked seeds.” Unlike angiosperms, gymnosperms produce an exposed seed or ovule, typically as needles and cones. Examples of softwoods include cedar, Douglas fir, juniper, pine, redwood, spruce, and yew trees. Simply put, hardwoods come from angiosperm trees, which reproduce via flowers that become an enclosed seed when pollinated, while softwoods reproduce by dropping needles or cones.
Differences in Growth and Grain
While the designation of lumber as hardwood or softwood is based on the reproduction cycle, trees in either category grow in specific ways that make it easier to differentiate between the two. For one, hardwoods are perennial, so they grow broad leaves in the spring which they lose in the autumn. They also grow more slowly than softwoods, which typically result in lumber that is denser. However, there are examples of “softer” hardwoods, such as balsa. Comparatively, softwoods are annual evergreens. Needles may shed, but they keep their greenery year-round. They grow much faster than trees that fall into the hardwood category, making the lumber easier to cultivate and harvest.
Since hardwoods typically have a slower rate of growth than softwoods, their pores are visible on a microscopic level, leading the wood with a much more distinct grain. Softwoods, on the other hand, are virtually pore-less on a microscopic level, giving them a lighter grain. Their rate of growth also effects how inherently fire-resistant they are: hardwoods are usually more inherently fire-resistant while softwoods are usually more flammable.
Differences in Uses
Because hardwoods have a more distinct, luxurious grain pattern than softwoods, and due to their rate of growth, they are used most often in high-quality furniture, decks, flooring and construction. While hardwoods are often more cost-prohibitive and sometimes more challenging to manipulate, their higher density allows for longer lifespans in many cases. Softwoods, with their more subtle grain and ease of harvest, are used in timber products which have a lower price-point, including furniture, medium-density fiberboard, and building components such as windows.
While approximately 80-percent of green plants that exist currently fall within the hardwood category, more than 80-percent of timber comes from softwoods. As the most commonly used type of timber, softwoods are frequently used in furniture, medium-density fiberboard, and building components, such as windows.