Andrea Barino, age 14, of Mesa, Ariz., for her question:
IN LUMBER, WHAT IS SOFTWOOD AND HARDWOOD?
Lumbermen divide lumber into two main classes: softwood and hardwood. These classes are not based on the softness or hardness of the wood. They refer to the kind of tree from which the lumber came.
Some softwood lumber is harder to cut or saw through than most hardwoods. Also, lumber from certain hardwood trees is softer than lumber from most softwoods.
Lumber is also classed by its condition. Rough lumber has straight sides and edges, but is rough and splintery. Dressed lumber comes in smooth, evenly cut boards. Worked lumber is dressed lumber that has a design cut in it for decoration or to make boards fit together.
Softwood lumber comes from trees called conifers. The word refers to the cones in which the seeds of most softwood trees develop.
Common conifers include pines and firs. These trees have thin, waxy needle shaped or scale like leaves. They are also called evergreens.
Pines, Douglas fir, Western true firs, hemlock and redwood produce most softwood lumber. Their wood is used for doors, frames, panels and other building material.
Hardwood lumber is sawed from broad leaved trees. These trees are usually deciduous, which means that they lose their leaves in autumn. Hardwoods used for lumber include oak, maple, yellow poplar, sweet gum, birch, tupelo, cottonwood, aspen and beech.
Tropical hardwoods include mahogany, ebony, teak and rosewood. They produce beautiful lumber that is used in fine furniture. Hardwoods are also used for paneling, flooring, baseball bats, tool handles and many other items.
Much hardwood lumber is sawed into small pieces called hardwood dimension lumber. This cuts out defects and provides greater usefulness. Manufacturers use it to make chair arms, piano legs and other furniture parts.
When furniture or tool factories want plain blocks of hardwood, they order rough hardwood dimension. If they need trimmed, molded or sanded wood, they order surfaced hardwood dimension. If the manufacturer wants to buy parts of a chair, such as legs, arms or seats, that are ready to be assembled, he orders completely fabricated hardwood dimension.
A board foot of lumber is a piece one foot long, one foot wide and one inch thick. It equals 0.083 cubic foot.
Flooring is lumber used in floors. It is usually hardwood, one inch thick and two to four inches wide.
A plank is a piece of lumber two to four inches thick and four or more inches wide.
Plywood is a panel made of thin layers of wood glued together under heavy pressure.