Abstract:

Wolong is situated between latitude 30˚45′—31˚25′ north and longitude 102˚52′—103˚34′’east, and belongs to Wenchuan of Sichuan Province. It is one of the Chinese natural preserves under the protection of the state. Wolong has a large area of Davidia involucrata forests. Davidia involucrata is a tertiary relict species in our country. In this paper, the Davidia involucrata forests are analyzed on the basis of the floristic geographical composition, the dominant species and the physiognomy and structure of the community. The discussion is made mainly on the following points:

1. The floristic composition of the community in the site of Davidia involucrata forests consists of 154 species which belong to 60 families and 110 genera. This shows that the floristic geographical elements are very complex and varied. Among the 110 genera are relic floristic compositions of the tertiary period, such as Lithocarpus, Fagus, Helwingia, Tetracentron, Cercidiphyllum, Euptelea, Acer, Tilia, Juglans, Pterocarya, Viburnum etc, from which we can see the relic nature of the community.

2. In mixed Davidia involucrata communities, the Davidia involucrata is distributed in each layer, from that of seedlings to that of arbors, which indicates that this species is a stable dominant one.

3. The analysis of the life form spectrum, leaf-size class and leaf form from the 145 species showed that the nature of mixed Davidia involucrata communities is mixed deciduous-evergreen broadleaf forests.

4. The dynamics of communities shows that the mixed Davidia involucrata communities are stable and developmental communities.