Hemlock is classified as a softwood, despite its relatively high density compared to many other woods in this category. The terms “hardwood” and “softwood” are misleading, referring to the botanical origin of the tree rather than the physical hardness of the lumber. This classification is confusing because some species, particularly Western Hemlock, possess a strength-to-weight ratio that rivals certain hardwoods. Understanding this distinction requires examining the tree’s reproductive structure and cell anatomy.
The Botanical Distinction Between Hardwood and Softwood
The difference between wood types lies in the seed structure of the parent tree, not the wood’s ability to resist indentation. Hardwoods come from angiosperm trees, which are flowering plants that produce seeds enclosed in a fruit or shell. These trees are typically broad-leaved and deciduous, shedding their leaves seasonally. Hardwood anatomy is defined by the presence of vessel elements, or pores, which are large cells responsible for water conduction.
Softwoods originate from gymnosperm trees, which reproduce using “naked” seeds usually housed in cones. They are overwhelmingly conifers, characterized by needles or scale-like foliage and remaining evergreen year-round. Hemlock (genus Tsuga) is a conifer, automatically classifying it as a softwood. Softwoods lack the large vessel elements found in hardwoods, relying instead on simpler, uniform cells called tracheids for water transport.
Practical Characteristics of Hemlock Lumber
Hemlock lumber exhibits a generally straight grain with a coarse and uneven texture, sometimes showing an interlocked or spiraled pattern. The heartwood is typically a light, pale brown to reddish-brown color, making it visually appealing for interior applications. Although botanically a softwood, species like Western Hemlock are notably dense and strong, contributing to the misconception about its classification.
The wood’s density is not uniform, creating a contrast between softer earlywood and harder latewood. This disparity can affect workability, causing the wood to splinter easily during machining or plane poorly. Despite these challenges, Hemlock accepts glue, paint, and stains well, making it versatile for finishing. Its strength, stiffness, and shock-absorbing properties are excellent for a softwood, with a reported Janka hardness ranging from 500 to over 600 pounds-force.
Typical Uses for Hemlock Wood
Strength, relatively light weight, and availability make Hemlock a popular choice in construction and structural applications. It is widely used for framing, such as studs, joists, and rafters, providing support for wood-frame housing. Hemlock is also manufactured into subflooring, plywood, and various forms of crating and boxing materials.
The wood is often utilized for interior millwork, including moldings, trim, and door components, because it holds a clean profile and resists warping. Western Hemlock is valued for its clear, straight-grained lumber, which is favored for visible trim applications. Its moderate resistance to wear allows it to be used successfully as an alternative to more expensive hardwoods for stairs and paneling.