The hardest commercially available hardwood is hickory and it is five times harder than aspen one of the soft hardwoods.
The softest hardwood.
For example balsa wood is known as one of the softest and least dense types of wood yet it is categorized as hardwood.
First it is virtually unobtainable and not commercially available outside of its natural range in central south america.
Wood is categorized as either softwood or hardwood based on physical structure and makeup.
Although classified as a hardwood alder is one of the softest of all hardwoods and is more commonly referred to as a semi hardwood.
However the wood is omitted from this list for two main reasons.
On a hardness scale alder ranks just above pine and poplar.
Classifying wood as either a hardwood or softwood comes down to its physical structure and makeup and so it is overly simple to think of hardwoods as being hard and durable compared to soft and workable softwoods.
Other soft hardwoods.
Because hardness is an important factor and hardness.
Similarly wood from the yew tree which is one of the toughest woods and is harder than most types of oak is classified as softwood.