Hardwood is heavy, expensive, and dark in color but they are weather resistant and can last for hundreds of years.
Since hardwoods are having a high grain density, there is a lot of wood material for the laser to vaporize.
They will produce thick smoke which can reduce your operational visibility and sometimes can be hazardous to your health.
I would recommend cutting hardwoods in a good ventilated setup with air assist and smoke extractor running at the same time.