Thinking About Wood
(Part I)
This is the first in a series of articles dealing with wood and its properties.
Hardwood and Softwood Trees
What is a Hardwood Tree?
A hardwood tree is defined as a woody treelike member of the plant phylum Angiospermata, meaning those plants whose seeds are enclosed in a membrane. It is tempting to think of hardwoods that shed their leaves in the winter but there are many examples in the tropics and subtropics of trees that are angiosperms that are evergreen. Common examples of angiosperms are apple, maple, balsa,
What is a Softwood Tree?
A softwood tree is defined as a woody treelike member of the plant phylum Gymnospermata, meaning those plants whose seeds are not enclosed in a membrane (a further complication is that not all plants produce seeds but that's another story). Again, it is tempting to think of softwoods as those trees that keep their leaves in the winter but, again, there are exceptions. Common examples of softwood trees are pine, redwood, juniper, fir and gingko.
Were you Paying Attention?
Those of you who were will have noticed that balsa was listed as a hardwood. Yet, model makers use balsa because it is so soft and easy to carve and cut. On the other hand, gingko, which has most of the characteristics of a hardwood; branching habit, decidious; is a softwood. You may also have noticed that juniper was listed as a softwood, but some junipers are harder than most temperate hardwoods. Juniperus ashei, in particular, has a density of 0.65 oven dry. It is quite dense.
Conclusion
As you undoubtedly have concluded, not all hardwoods are hard and not all softwoods are soft. If you are a stickler for precision (I must admit I am) then you would be more precise in classifying woods as either Gymnosperms (naked seeds) or Angiosperms (covered seeds). While you're thinking about that I'm going to the lumber store to buy some softwood pine for my new deck and on my way back I'll pick up some hardwood balsa to fix my friend's model airplane.
We'll talk again in part II.
Rick Hurst
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