Trees in a subtropical forest in Okinawa Island, Japan were studied to see how they are distributed based on the shape of the land. Most trees were found in groups, with different species preferring different types of land features like ridges or valleys. The researchers found that the distance between tree species was related to how steep or flat the land was. Trees on steep slopes might grow back after landslides, while trees on ridges might grow back after gaps in the canopy. Some less common tree species were found near streams where more common trees were scarce. This study shows that different tree species like different types of land in a subtropical forest.