Softwoods originate from coniferous trees (also known as evergreens, or gymnosperms). Rather than losing their leaves all at one time, they tend to shed their leaves (which resemble and are called "needles") throughout the year and bear cones. Hardwoods, on the other hand, come from deciduous trees which lose their leaves throughout the year and produce seeds covered with some kind of covering (sometimes a fruit or nut).
There are hardwood and softwood forests scattered throughout the world. Boreal forests located in the northern latitudes contain mostly softwoods, while the equatorial regions of the world grow mostly hardwoods.
Softwood trees include cedar, cypress, fir, hemlock, larch, pine, redwood, spruce and yew. Hardwood trees include oak, beech, ash, maple and cherry.
Most things constructed of wood today are made from softwood. Softwood is less expensive to use. It grows more faster than hardwood, and since it can be replenished more quickly it is thought to be a more environmentally friendly option. Hardwoods are often used for their beautiful grains, and high-end furniture and floors are made with a hardwood like oak or maple.
A common misconception is that hardwoods are denser, or harder than softwoods. This is not necessarily true. Balsa wood, which is very lightweight and used expressly for this reason, is considered a hardwood. Conversely, Douglas fir is one of the strongest woods, and it is a softwood.