it's moderately hard wood
A soft hardwood is the way in which alder trees (Alnus spp) tend to be described. Specifically, it is a member of the birch family (Betulaceae). It therefore is considered a hardwood. But its wood...
soft
They dry hard. I've been told you can use them for fence posts as long as you drive the nails when the wood is green.
All conifer wood is classed as softwood.