what are building materials can we get from the tropics?

Answer 1

Bamboo floors are very popular at the moment.

Actually bamboo has several uses:

When treated, bamboo forms a very hard wood which is both light and exceptionally tough. In tropical climates it is used in elements of house construction, as well as for fences, bridges, toilets, walking sticks, canoes, drinkware, furniture, chopsticks, food steamers, toys, construction scaffolding, and as a substitute for steel reinforcing rods in concrete construction.