using a wooden tub outdoors

Would it be okay to place a tub outdoors with its top at the level of the deck and its bottom resting on a concrete or stone slab?
We have termites in our area which is one block from the beach and thus fairly humid as well. Should we therefore use the Asnaro wood? When it’s wet, does Asnaro also have the pleasant aroma like Hinoki?

Yes, wooden tubs can be used outside but some precautions must be taken to protect it from direct sunlight and dryness.
There is no problem as long as the tub is protected with a cover from direct sunlight while it is empty. A soft spa thermal cover would improve also the situation in winter and prevent the risk of cracks caused by sudden drops in temperature.
For the termites, there should be no problem, you should build it into the deck in such a way that air can circulate around.
Asnaro has a nice and relaxing aroma as well, actually more intense than hinoki.