Analysis of the leaf-shedding time of the Chinese parasol tree: is the French plane tree a Chinese parasol tree?

Chinese parasol tree is also known as qingtong and tongma. In the family Sterculiaceae, the genus Firmiana has a total of 15 species, and those distributed in China include Firmiana simplex, Firmiana hainanensis and Firmiana major. They generally shed their leaves in late autumn, in the north around October and in the south in November. The tree we often know as the “French plane tree” does not actually belong to the family Sterculiaceae, but to the family Platanaceae in the order Rosales. The “French plane tree” has the scientific name Platanus orientalis, also known as the Oriental plane and the jiumoluoshi tree, and enjoys the reputation of “king of street trees.” Another commonly heard tree, the “paulownia,” also does not belong to the family Sterculiaceae, but to the family Scrophulariaceae, genus Paulownia.

1. Chinese parasol tree

Appearance: tall and imposing, with a trunk that has no knots and rises straight upward, holding aloft a huge emerald-green umbrella of foliage with a spirited bearing. The bark is smooth and emerald green, and the leaves are dense; from trunk to branches, it is all lush and verdantly clean and elegant. “A single plant stands like green jade, a thousand leaves settle like green clouds”: these two lines of poetry vividly capture the charm of the Chinese parasol tree's jade-green leaves and emerald trunk and the dancing shade of its foliage.

Growth cycle: the Chinese parasol tree generally germinates 4 to 5 weeks after sowing and becomes a tree in 5-6 years; the flowering period is June-July, and the leaf-shedding period is October-November.

2. French plane tree (Platanus orientalis)

Appearance: the crown is broadly bell-shaped; the trunk bark is grayish brown to grayish white and peels off in thin flakes. Young branches and young leaves are densely covered with brown stellate hairs. The leaves are palmately 5-7 lobed, with the deep lobes reaching the middle, the lobes longer than wide, the leaf base broadly wedge-shaped or truncate, the leaf margin toothed, and the veins palmate; the stipules are collar-shaped. The inflorescence is capitate and yellow-green. Most of the nuts are gathered into a spherical whole, with 3-6 balls forming a string, and the persistent style is long and bristle-like, while the fruit stalk is long and drooping.

Growth cycle: the flowering period is April-May, and growth is most vigorous in June-July; leaf shedding generally varies by region. In North China, leaves generally fall in November-December each year, but a small number of leaves overwinter on the tree and do not fall completely until around spring.

3. Paulownia

Appearance: the bark is gray, grayish brown or grayish black, smooth when young and longitudinally fissured when old. It branches falsely dichotomously. The leaves are simple, opposite, large, ovate, entire or shallowly lobed, with long stalks, and the stalks bear downy hairs. The flowers are large, pale purple or white, in terminal panicles composed of many compound cymes. The calyx is bell-shaped or dish-shaped, thick, and 5-parted deeply, with unequal lobes. The corolla is bell-shaped or funnel-shaped, with the upper lip 2-lobed and recurved and the lower lip 3-lobed, straight or slightly curled; there are 4 stamens, 2 long and 2 short, inserted at the base of the corolla tube; and 1 pistil with a slender style. The capsule is ovate or elliptical and opens along the back suture when ripe. The seeds are mostly oblong, small and light, with striped wings on both sides.

Growth cycle: paulownia grows rapidly and can become timber in 7-8 years. Roots are buried from mid-to-late February to the end of March, flowers bloom in March-April, and leaves fall in October-November.