The island is small but that doesn't mean the volcano is
Krakatoa is located on an island in Indonesia. It's surrounded by water from the Sunda Strait. Not much of land forms are present since the island is small with the base of the Krakatoa volcano taking up the majority, if not all, of the small island and the past eruptions of Krakatoa have caused the landscape to be one that is deserted. If there were to have been trees surrounding the volcano in the past, they wouldn't have lasted very long for an eruption from the Krakatoa volcano would have wiped them out quickly. The terrain would have most likely been rocky or bumpy from the cooling and hardening of the lava that flowed out of the volcano during eruptions.