Spring is an awakening time for Minnesota trees. As the air warms, sap rises from the roots, carrying nourishment to the branches.
Coniferous trees develop new shoots. The shoots expand to form new stems and needles. On deciduous trees, buds begin to swell. Then they open into new shoots and leaves.
Most deciduous trees reproduce by forming flowers. In some species, each flower has both male and female parts. Others have separate male and female flowers. In yet others, male and female parts develop on separate trees.
For seeds to form, pollen from the male parts must come into contact with the female parts. In many species, pollen is carried by wind. In species with fragrant or showy flowers, pollen may be carried by insects called pollinators."
Deciduous tree seeds are distributed in various ways, too. The wind carries seeds with wings, such as maple and aspen. Birds and mammals spread seeds hidden in fruits and nuts. Water and gravity also carry seeds away from their parent tree.
Coniferous trees have two kinds of cones. The male cones produce pollen. The wind carries pollen through the air. Some lands on female cones. The pollen and eggs join to make a new seed. The seeds have tiny wings that help them fly through the air when they fall from the cones.