Table 3 Identification information of the plant material used in your study

Fraxinus pennsylvanica

Fraxinus pennsylvanica, deciduous trees, 10–20 m high; Bark gray, rough, wrinkled. Branchlets reddish brown, cylindrical, yellow pilose or bald, old branches reddish-brown, smooth and glabrous. Feather compound leaves are 18-44 cm long. Petiole 2-5 cm long, base hardly inflated.

Ailanthus altissima

Ailanthus altissima, deciduous tree, with a height of more than 20 m, has smooth and straight bark. Leaves are odd-pinnate compound leaves, 40-60 cm long, petioles 7–13 cm long and lobules 13–27. Small leaves are opposite or nearly opposite, papery, ovate-lanceolate, 7–13 cm long, 2.5–4 cm wide, apex long acuminate, base oblique, truncated or slightly rounded, with 1 or 2 coarse serrations on each side, one gland on the back of the tooth, dark green on the leaf surface, grayish-green on the back, and stinking after soft crushing.

Sophora japonica

Sophora japonica, a tall tree, has the largest planting area in Beijing. Its bark is grayish-brown with cracks. The leaves are pinnately compound leaves with a length of 25 cm. Lobules are oval oblong in shape, opposite or alternate, 2.5-6 cm long and 1.5-3 cm wide. The back of the leaf is grayish-white with short hairs. 2 small stipules, drill-shaped. Panicle terminal is pyramid-shaped, up to 30 cm long.