When Krsna walks in Vrindavan as Madhava, carrying his flute tucked in his belt, then the trees which have branches laden with fruits and flowers, are trying to touch Krsna’s feet. The bees are just singing the glories of Krsna. Bhagavatam says that these bees must have been great devotee sages in their last life.
The trees are thinking, ‘We are so unfortunate. It is due to our sinful activities that we have taken birth as trees and therefore we cannot follow Krsna on his pastimes in the forest