From the information I recovered, softwoods or hardwoods are indeed defined by cell structure softwoods have more rectangular sap vessels which will carry on through the entire length of the trunk of the tree. these type of cells if I remember correctly are called tracheids, or tracheid cells,or trachoid. will look that up. also Softwoods seem to have no rays, or horizontal sap vessels that run radial in the wood, seeing the fact the membranes of the tracheids allow for moisture to transport through to the parallel running cells.
Also I have heard that all coniferous trees are softwoods, yet I'm not entirely sure about this, so if anyone could give some conclusion, experts help us out.
Yours sincerely Ruud