Wajih writes:

1-Do you mean that by smoking the hives you will have all or most of the
queens  rise up to the upper story and leave the original hive queenless
with some brood down?

exactly

2-How affected honey production?

the purpose was to increase the number of hives. In an area where the honey comes in summer, much later, dividing in early spring doubles the honey production (2 hives instead of 1)

3-Why the bees are shifted to the coast in winter and not kept in the warmer
valley in your country.

Along the coast there is winter rain and a splendid bulidup period (Jan to April) on wild flowers, eucalyptus, etc. In the desert, nothing going on.

4- My last point which is important , we noticed that the very hot weather
in our valley kills most of the mites . Though the hives become weaker , but
start to grow healthy in Autumn. Why you don't have the same in your valley.

I don't live there anymore. I don't know about mites in the desert, but I have read that they seem to be less trouble where it is very hot, than they are here, for example, where it tends to be damp and cool during summer.

PB
Ithaca NY  U S A