2. Birch: a deciduous tree with a trunk as high as 25 meters and 50 centimeters thick. There are white smooth paper bark, which can be peeled off layer by layer, and you can write on the thin bark with a pencil. The leaves of Betula platyphylla are simple and alternate, with serrated edges. The flowers are monoecious, and the male inflorescence is soft and drooping. In spring, the leaves on the trees bloom before they grow. Birch fruit is flat and small, called samara, which is easily blown up by the wind and floated far away.