Plants such as brackens, flowering ferns, Japanese butterburs, Japanese arrowroots, yams, and Japanese garlics grew and prospered easily in the newly created secondary forest environment, the new environment known as copses, and became steady food resources for the Jomon people.
ワラビ、ゼンマイ、フキ、クズ、ヤマイモ、ノビルなどの縄文人の主要で、安定した食料資源となった有用植物が繁茂しやすい二次林的な環境、つまり雑木林という新しい環境を創造したことになる。