I think the wood found in homes is pressure treated lumber which I don't believe is structurally any stronger than non-pt wood, but helps wood withstand the elements and wards off termites, microorganisms and fungal decay. The most common types of Pressure Treatments (at least that I am aware of in Canada) are Alkaline Copper Quaternary (ACQ) and Copper Azole (CA).
However, the wood material usually used to build these mid-rise buildings is cross laminated timber, which does add significant strength to the wood materials. Really cool material actually!