It does not mean 'hardness' in the normal sense, but is a botanical classification. For example, the lightest-known woods are termed 'hardwoods'. Hardwoods are more complex, being of more recent evolution. They occur in all climate types where trees grow. They bear seed-containing fruit and come from the botanical group called Angiosperms.
Softwoods generally come from coniferous or needle-leaved trees.
They are simpler in structure and more ancient than hardwoods. They grow mainly in temperate and cool climates and comprise about 600 species. They are non-porous and come from the botanical group called Gymnosperms. The Wilderness Society, Australian Conservation Foundation, Colong Foundation, Rainforest Conservation Society, Friends of the Earth Sydney and other groups are campaigning now to end all native forest logging immediately. What We Need to Grow are Durable Native Softwoods .