About Wood

 

Every day, each of Earth’s 6.7 billion inhabitants uses wood – about one-half gallon on the average. But the average American uses 3.5 times this much wood.  Should Americans be using less wood? 
Steel, aluminum, and concrete are often mentioned as substitutes for wood, but these resources are not renewable.  Wood is the only natural resource on Earth that is renewable, recyclable and biodegradable.  The only energy required to grow a tree is the sun.  As trees grow, they remove carbon dioxide from  air, and give off oxygen.  By weight, total U.S. wood consumption exceeds combined consumption of steel and concrete.  Wood manufacturing processes consume only 4 % of the energy used by all primary industrial raw material manufacturers. Steel and concrete manufacturers comprise 56% of the energy used by all primary industrial raw material manufacturers.  If the energy required to manufacture a four-pound block of pine had been used to make aluminum, the resulting piece of aluminum would weight one ounce.
Global demand for wood will increase by 50% by the year 2020, but governments around the world are establishing more new forest preserves where harvesting is prohibited.  Left unanswered is this critical question:  Where will we get our daily wood?  We believe the world should be using more wood, not less, because no other natural resource on Earth can match its environmental advantages.  But first, nations must make a major global commitment to growing our daily wood, just as we do our daily bread. 
Trees occur in many diverse orders and families of plants, and thus show a wide variety of growth form, leaf types and shapes, bark, and of course, woods. The earliest trees were tree ferns and horsetails, which grew in vast forests during the Carboniferous Period. Tree ferns still survive, but the only surviving horsetails are no longer of tree form. Later, in the Triassic Period, conifers appeared, and subsequently flowering plants in the Cretaceous Period. Most species of trees today are flowering plants and conifers.

                                       

 290 million years ago                              206 million years ago                             144 million years ago

Woods are generally classified as either being hardwood or softwood. This terminology can be a little misleading because it sometimes does not indicate the actual physical hardness or softness of a wood. The best example of this is balsa wood, which is classed as a hardwood although it is actually 'soft' to handle and can be easily carved.
Hardwoods are those which come from broad-leafed trees such as oak, ash, mahogany and maple. These trees produce seeds which form inside a ripening fruit. Their wood is close grained and has open vessels known as pores, and are called porous woods. The close grain helps to prevent the wood from splintering and pieces made from hardwoods will last well for hundreds of years if they are properly cared for.

                   

Hardwood cells                             Softwood cells

Softwoods come from conifers; evergreen trees which produce their seeds uncovered such as pine, redwood and cedar, usually in cone-like structures. Softwoods do not have pores and are called non-porous. They usually have a large open grain. With the exception of most pine species, softwoods are inclined to split or sliver if used for intricate pieces. As softwoods are not as durable as hardwoods, they are best finished with paint or several coats of polyurethane rather than just a wax or oil finish.