Abstract: Cerasus serrulata is a wild species of cherry blossoms, with beautiful flower color and tree shape. It is an important and rare ornamental plant resource ofCerasus. A relatively concentrated population of wild Cerasus serrulata was recently found in the northern mountainous area of Tianjin, which is located at the east of Yanshan Mountains. To clarify the population characteristics of wild Cerasus serrulata and explore its ecological habits, we carried out community investigation at three different slope positions (shady slope, ridge, and sunny slope) in Baxianshan Mountain National Nature Reserve of Tianjin. We examined the population structure and the change of species diversity of Cerasus serrulata community with altitude and slope position. Principal component analysis and redundancy analysis were used to explain the differences among communities and the influence of community structure on diversity. The results showed that: (1) Cerasus serrulata was a companion species in the deciduous broadleaved forest. The main species of tree layer in the community were Quercus mongolica, Fraxinus chinensis,Quercus aliena,Carpinus turczaninowii,Euodia daniell, Morus alba and Acer truncatum, while the main species of shrub layer were Rhododendron mucronulatum,Spiraea trilobata, Deutzia parviflora, Deutzia grandiflora, Celtis koraiensis andWeigela florid. The population structure and community structure of Cerasus serrulata varied across slope positions. (2) The age structure of Cerasus serrulata population showed an inverted “J” type. The regeneration status was the best in the altitude of 600-800 m and at the sunny slope. (3) Under different slope positions, the Shannon niche breadth of Cerasus serrulata population followed the order of sunny slope > ridge > shady slope. The species with the highest niche overlap with Cerasus serrulata were Salix sinicaand Quercus mongolica in shady slope, Euodia deniellii and Quercus mongolica in ridge, and Armeniaca vulgarisand Morus alba in sunny slope. (4) The diameter class distribution of tree layer showed an inverted “J” pattern. The diversity index increased first and then decreased with the increases of altitude. In different slope positions, the diversity index was the highest in shade slope and lower in the ridge and sunny slope. The diversity index of shrub layer was opposite to that of tree layer. The species diversity of the community increased with the development of the community, with the dominance of the dominant species being further increased. The companion species Cerasus serrulata population may decline in the shady slope and develop well in the ridge and sunny slope. Our results can provide a scientific basis for the protection and utilization of wild Cerasus serrulatepopulation in northern China.

Key words: wild Cerasus serrulata, population structure, niche, diversity, regeneration.