Is the Galapagos islands a tropical rain forest?

NO! Most of the Galapagos Islands are deserts. They get rain only in the highlands of the large islands. The exception are strong El Niño years when it can rain in all parts of the islands. The rain, however is too infrequent to allow the growth of tropical rain forests. Instead most islands in the Galapagos have giant tree cactuses. Most tree species actually have not been able to cross the ocean (except for those introduced by humans).