One of our first trees to bloom is the red maple (Acer rubrum). Here you see male red maple tree flowers blooming yesterday. The flowers are starting to release their pollen, some of which may fertilize the waiting stigmas of female red maple flowers.
At about the time that the trees are in leaf, those fertilized female flowers will have elongated into fruit in the form of double samaras (winged seeds) that spin through the air before they land and try to germinate into little trees.
Curiously, red maple samaras are reddish and fly in the spring, yet the samaras of sugar maple (Acer saccharum) are green and fly in the fall. (Images taken in Brooklin, Maine, on April 22, 2022.)