往後嘅實驗有相反嘅結果 杉樹送碳元素俾樺樹 ， 多過收碳返來 事關嗰時杉樹仲有葉 ， 而樺樹落曬葉
Later experiments had the opposite result: the fir tree sent more carbon to the birch than it received back, because the fir tree still had leaves, and the birch tree had dried its leaves