cutting firewood to teach and protect the nest branches.
—— Cai Yuanpei (president of Peking University, educator and revolutionary) wrote the general couplet of Cai's ancestral hall.
When Li Ao quoted it, he wrote the word "except" as "hoe" and "protect" as "Hu".
It means that even if you cherish bamboo, you should not uproot bamboo shoots on the roadside, and you should avoid branches with nests when cutting wood. My own understanding is that Mr. Cai should educate future generations to leave room for things and be compassionate.