Wood is generally separated into two categories: hardwood and softwood. But why is balsa wood, one of the softest woods of all, considered a hardwood? Why is a yew tree classified as softwood even though it’s much harder than many hardwoods?

The density of the wood actually has nothing to do with whether a wood is considered hard or soft. Instead, wood is categorized based on the type of seed the tree comes from. Trees that have seeds with a covering on them, either in a shell or a fruit, are considered hardwoods. Trees that have seeds that are unprotected are classified as softwoods.

So if toughness isn’t a factor in putting wood into categories, how can you determine how tough a piece of wood is?

The industry standard is to use the Janka Hardness Test, which measures the amount of force required to embed a .444-inch steel ball to half of the piece of wood’s diameter. You can learn more about this test and the trees it has tested by visiting this article on todayifoundout.com.