Wood 101 and more!

Learn the differences between softwoods and hardwoods, their lumber grades, uses and tree trunk structure.

There are two kinds of wood – softwoods and hardwoods. Contrary to their names, the “hardness” of the wood species does not define the characteristics. See the differences noted below.


  • Wood from coniferous (with needles)
  • Evergreen trees that grow quickly and can be cut easily
  • They tend to keep their needles throughout the year
  • Softwoods are frequently used as building materials
  • Examples of softwood trees are:
    • Cedar
    • Douglas fir
    • Juniper
    • pine
    • redwood
    • spruce
    • yew


  • Wood from broad-leaved trees such as oak, ash or beech
  • These are deciduous trees that shed their leaves during autumn and winter.
  • Are more likely to be used in high-quality furniture, cabinetry, and flooring
  • Examples of hardwood trees are:
    • Beech
    • Hickory
    • Mahogany
    • Maple
    • Oak
    • Teak
    • Walnut

Tree Trunk Structure

Growth Rings

  • Each year, a tree adds to its girth, the new growth being called a tree ring.
  • The most recently formed tree ring is the new wood near the outer part of a tree's trunk, just beneath the bark.
  • The oldest rings are smaller and near the center.


  • Is the cell layer of the growing part of the trunk
  • It annually produces new bark and new wood

Dead Bark

  • Is the outer bark of a tree, which is mostly dead tissue.
  • Is the tree's protection from the outside world.
  • Is continually renewed from within and helps keep out moisture in the rain, and prevents the tree from losing moisture when the air is dry
  • Insulates against cold and heat and wards off insect enemies


  • Is the living part of the tree, the outer portion within the bark of the tree
  • Is typically lighter in color than heartwood
  • Brings water and nutrients up from the roots through tubes inside of the trunk to leaves and other parts of the tree
  • The untreated sapwood of virtually all species has very little decay resistance.
  • As the tree grows, sapwood or xylem cells in the central portion of the tree become inactive and die. These dead cells form the tree’s heartwood.


  • Is the dormant, inner, and darker section of the wood
  • Is far less susceptible to decay and fungus
  • Has much less moisture than sapwood which means less shrinkage when dried
  • The heartwood of some wood species is naturally termite-resistant.

Live Bark

  • The inner, living bark is comprised of vascular tissue, called phloem, which serves as a conduit for the transport of sugars produced by photosynthesis in leaves to the rest of the tree.


  • Is the oldest part of the tree, at the very center

Medullary Rays

  • Are the thin horizontal rays that extend radially from the core of the tree toward the bark, perpendicular to the growth rings
  • Are essential and serve as a link between pith (center) and the periphery of the live tree
  • Perform various functions like food storage and transport of food and water