Benny Peiser noted evidence of self-sufficiency when Europeans first arrived. The island still had smaller trees, mainly toromiro, which became extinct in the wild in the 20th century probably because of slow growth and changes in the island's ecosystem. Cornelis Bouman, Jakob Roggeveen's captain, stated in his logbook, "... of yams, bananas and small coconut palms we saw little and no other trees or crops." According to Carl Friedrich Behrens, Roggeveen's officer, "The natives presented palm branches as peace offerings." According to ethnographer Alfred Mètraux, the most common type of house was called "hare paenga" (and is known today as "boathouse") because the roof resembled an overturned boat. The foundations of the houses were made of buried basalt slabs with holes for wooden beams to connect with each other throughout the width of the house. These were then covered with a layer of totora reed, followed by a layer of woven sugarcane leaves, and lastly a layer of woven grass.