ObjectiveCampus is the main activity area for youth groups.This article aims to provide theoretical basis and practical reference for further enriching the connotation of urban forests and improving the quality of school greening in the future by exploring the quantity and quality of urban forest in the school. At the same time, it is hoped that the construction of campus urban forest and the expansion of urban forest function will be paid more attention to in order to truly meet the needs of urban youth groups.
MethodThis paper analyses the urban tree canopy (UTC) in 984 schools within the Sixth Ring Road of Beijing. Analysis was made based on World-View-2 remote sensing images with a resolution of 0.5 m in 2013 and the tree canopy coverage grid and vector map. In addition, 126 schools were randomly selected and their urban forest structure was investigated by field sampling.The survey included tree species, DBH, tree height and crown width.
ResultThe results showed that the existing urban tree canopy rate (EUTCR) of universities, high schools and primary schools were 31.91%, 16.52% and 17.08%, respectively, and the potential urban tree canopy rates (PUTCR) were 4.81%, 0.62% and 0.42%, respectively. The species richness index (R), Shannon-Wiener index (H) and Pielou index (J) were 6.30, 1.55 and 0.91, respectively. The species diversity of new campus was lower than that of old campus; the average DBH, crown width and tree height in the school were 23.93 cm, 6.02 m and 7.80 m, respectively.
ConclusionThe EUTCR in school was lower than the average level in Beijing urban area, and PUTCR in school was insufficient.The species richness of universities was higher than that of primary and high schools, and the species diversity of same kind of schools was also quite different.There were many young and middle-aged trees with DBH of 10−20 cm, crown width of 4−6 m and tree height of 5−10 m in the school, showing that the potential of natural expansion of tree canopy was strong, and it is a reserve force to improve the EUTCR in the future. In addition, our study also shows that the EUTCR, the size of tree canopy patches, and the average DBH of trees are significantly positively correlated with the school area.