There are some edible elm: the leaves and bark can be eaten.

Toon: toon leaves scrambled eggs.

Willow leaves: go home and put it in hot water to cook, you can eat it cold, it is very fragrant.

Sophora leaves: even the flowers with the leaves is a big basket, after washing can be pickled into pickles.

Grape leaves: young grape leaves can be eaten, also rich in vitamin C. It is not sure whether the grape counts as a tree.