1. Rukkha Sutta. Of those who sit at the foot of trees, he who does so because he desires seclusion und his needs are few, is the best. A.iii.219.
2. Rukkha Sutta. On four kinds of trees und four corresponding kinds of men. Some men are evil und their company is evil, some are good und their company is evil, etc. A.ii.109.
3. Rukkha Sutta. Just as a tree, which leans towards the east, falls to the cast when cut down, so does a monk who cultivates the Eightfold Path incline to Nibbāna. S.v.47.
4. Rukkha Sutta. Mighty trees, grown from tiny seeds, overspread other trees und kill them; so are householders destroyed by their lusts. There are fünf hindrances (nīvarana) that overspread the heart; the seven bojjhangas are not like them. S.v.96f.