NATURE NOTE #31 October 28, 2021
Introduction:
Anytime I teach a Forestry Merit Badge class, I ask the scouts why we need the forest. They readily answer that it supplies oxygen, provides habitat for animals, and finally, someone will mention that it provides us with wood. Oh yeah, we have a tendency to forget that rather important part of the benefits of the forest. We won’t go into all of the many products we get from trees, but today let’s talk about that material that provides these products.
Our Current Topic: Wood
Scouts don’t have much knowledge of wood other than you need it for campfires. They have not been taught anything about it in school, and unless their Dad is a woodworker, probably not much at home. So let’s look at some facts about wood that you might be able to pass on to our scouts that might be useful in their later life.
Hardwood vs Softwood. These commonly used terms are not accurate when it comes to describing the physical density of wood. Softwood generally refers to wood from evergreen trees such as pine, spruce, and fir. This wood is generally used in house framing, construction, crating, utility poles, plywood construction, and manufacturing of cardboard and certain paper. It grows relatively fast, is easily worked and has good physical properties for it normal uses. Hardwood refers to wood from deciduous trees (those that lose leaves in the winter) such as oak, maple, ash, hickory, etc. This wood is usually more dense, or hard, than the softwoods, but not always. Basswood for example is softer than most softwood, making it a favorite of woodcarvers. Hardwoods are the “inside” wood used for flooring, cabinets, stairs, trim, furniture, picture frames, and other products showing its beauty and color. The lesser quality or “grade” of hardwood usually finds its way to pallets, railroad crossties and other products requiring high durability and strength but not nice appearance. High grade paper – such as many books - is also made from hardwood pulp.
Wood from various tree species has different chemical and physical properties that to a large degree, determines the use. For example, white oak is used for the construction of barrels in which bourbon is aged. This is because white oak, unlike red oak, does not have a porous structure that would leak. Crossties need to be very strong, durable and flexible, so the lower grade red oak often goes for this use because it has these characteristics. Yellow poplar grows very tall and straight, making it ideal for uses requiring very long pieces of lumber that are not common on many other trees that tend to branch out early leaving a much shorter “bole” (trunk). Some wood is more flexible than others, some has higher resistance to decay (Black locust), and some just look nice when finished into furniture (maple, cherry). All wood is not alike, but young scouts have not been exposed to this knowledge.
Scouts usually know that the trunk of the tree transports water from the ground up to the leaves, and moves “food” from the leaves to other parts of the tree, but they don’t know how this occurs. When you look at the end of a log or stump, most of what you see is called xylem. This is what carries the moisture and nutrients up the tree. Notice that the most interior part of the xylem is usually darker in color that the outer wood. This interior wood is called heartwood, and is basically dead material. The lighter outer wood, called sapwood is where the moisture (sap) is moving up the trunk. If you have chopped through a log, you have experienced this structure. So how does the leaf-produced food get dispersed? It moves down the trunk through the thin layer of phloem that is outside of the xylem and just inside the bark. Within that tree trunk, there is a two-lane highway that makes it all work, each lane carefully laid out within the anatomy of the tree.
When tree logs are sawed into boards the internal anatomy is displayed. Different boards will have different amounts of heartwood, sapwood, etc. and this physical difference is what causes twisting and warping as the moisture is removed from the wood. This makes the drying of lumber a critical element of the production process. Improper drying can result in poor stability of the lumber you want to be straight.
There’s much more I could go into about wood, but the idea here is to get scouts thinking about a material – a natural resource – that is so common that it is often overlooked. As a product of nature no two pieces of wood will ever be identical.
Opportunities:
There are lots of opportunities for scouts to learn about wood. A visit to a sawmill or drying facility might be very informative (safety issues may be a problem), as well as visiting a woodworker or craftsman using wood to make a product. Visit a lumber store and look at lumber and plywood. Have scouts make a list of all the wood products they commonly use. While all of this might seem a little removed from “nature education” it is not. These products all started as a seedling out in the forest, fighting for survival, and growing in natural elements it had no control over. Only with proper forest management can we continue to enjoy the properties of wood in our daily lives AND continue to maintain and preserve the forest for our future to supply oxygen, habitat, watershed protection, and recreation areas. Understanding the uses and characteristics of wood will enhance the Scout’s need to take care of that forest.
Thanks for reading NATURE NOTES. Let me hear from you at
Bob Garst
