Fig. 1

Spatial distributions of eleven dominant tree populations of different stages in a 0.98 ha (140 × 70 m) old-growth oak broad-leaved mixed forest plot in the Qinling Mountains, China. QA is Quercus aliena var. acutiserrata Maxim.; AC is Acer caesium subsp. giraldii (Pax) E. Murr.; UG is Ulmus propinqua Koidz.; CP is Cerasus polytricha (Koehne) Yü et Li; SP is Symplocos paniculata (Thunb.) Miq.; AG is Acer ginnala Maxim.; PA is Pinus armandii Franch.; CK is Crataegus kansuensis Wils.; MH is Malus hupehensis (Pamp.) Rehd.; TV is Toxicodendron vernicifluum (Stokes) F. A. Barkl.; QL is Quercus wutaishanica Blume. Juvenile tree means 5 cm ≤ DBH < 10 cm, Medium tree means 10 cm ≤ DBH < 25 cm, and large tree means DBH ≥ 25 cm