Choosing Project Wood
General
Lumber is available in 2 main categories, hardwood and softwood.
Quite simply, hardwood is harvested from any deciduous (leaf
bearing) tree. While softwood is from coniferous or needle
producing trees. However a wood worker also needs to decide if
an engineered wood product like plywood is better suited for the
job.
We will demystify the these 3 classifications by taking a close
look at the 3 main choices a wood worker has to face when buying
project wood.
Hardwood Looking at hardwoods first, it is important to remember
that these classifications really have no bearing on the true
hardness of the wood, not all hardwoods are "hard". Species like
poplar are much softer then pine even though poplar is
classified as a hardwood.
Some of the more common domestic hardwoods include, oak, maple,
birch and poplar although your choices certainly aren't limited
to these four. For exotic species there are too many to list but
teak, mahogany, rose wood and purple heart are just a few.
Softwood Softwoods on the other hand include species like
spruce, fir, pine and cedar and are often cheaper to buy then
hardwoods. This is mainly because softwood trees grow taller and
straighter than hardwood trees. This yields more lumber per log.
Along with the fact that most softwood is harvested domestically
it is the project wood of choice for most outdoor projects and
for many indoor ones as well.
How do you choose project wood? There are a number of factors
that need to be considered when deciding which wood to use for
what project. There are no set rules stating what wood to use
for an indoor or outdoor project. Basically the characteristics
of the species will determine whether or not it will stand up to
the punishing conditions of the outdoors or if it better used
indoors.
Both hardwood and softwood can be used for both indoor and
outdoor applications but some are more resistant to UV and
moisture then others. These are the ones that should be chosen
when being used outside.
These particular species have natural oils and resins that fill
the cells of the wood and provide, in some cases, very good
protection against rot and insects. Species like cedar for
example last for decades in direct contact with the ground while
spruce would be rotten in under 5 years.
Of course cedar is a softwood and is used a lot throughout the
furniture and house construction industry. However, some
hardwoods also have very good resistance to rot and insects.
Species like teak and mahogany are used a lot in the tropics for
boat construction, but since the cost of these exotic hardwood
species is so much in North America we tend to use softwood in
the outdoor applications.
Another important factor is whether or not you want you intend
to use a clear finish or paint to protect your project. Cedar
needs to be sealed to prevent oils from leaching through the
paint. Some species of hardwood like poplar and birch are great
for accepting paint but have a tendency to blotch when stain is
applied.