Bel Tree

bilva—bel fruit

So along with other little cowherd boys, Kṛṣṇa and Balarāma went into the pasturing ground and took charge of the calves and played with Their playmates. While taking charge of the calves, sometimes the two brothers played on Their flutes. And sometimes They played with āmalaka fruits and bael fruits, just like small children play with balls.
(Kṛṣṇa Book 11)

[The gopīs said:] ‘O cūta tree, priyāla tree, panasa, āsana and kovidāra! O jambu tree, O arka tree, O bel, bakula and mango! O kadamba tree, O nīpa tree and all other trees living on the bank of the Yamunā for the welfare of others, please let us know where Kṛṣṇa has gone. We have lost our minds and are almost dead.
(CC Antya 15.32)

There were cantaloupes, kṣīrikās, palm fruits, keśuras, water fruits, lotus fruits, bel, pīlus, pomegranates and many others. Some of them are variously known in different places, but in Vṛndāvana all of them are always available in so many thousands of varieties that no one can fully describe them.
(CC Antya 18.105)