Abstract:

In this experiment, freezing injuries in winter for the 1-year-old seedlings of 19 landscaping tree species common in the central Shanxi were compared to examine the winter survival ability of landscaping tree seedlings and to provide a practical reference guide for seedling propagation in the area. The results indicated: (1) the 1-year-old seedlings of Acer mono, Platycladus orientalis, Fraxinus pennsylvanica, Euonymus bungeanus, Koelreuteria paniculata, Gleditsia japonica, Syringa reticulata and Ligustrum obtusifolum could safely survive winter in the area, without or with little freezing injuries. Seedling propagation is appropriate for these species in the area. (2) The seedlings of Firmiana simplex and Hibiscus syriacus suffered most serious freezing injuries, resulting in very low survival rates despite under protection in the winter. Seedling propagation is not appropriate for the two species in the area. (3) The seedlings of Cornus alba, Albizia julibrissin, Pterocarya stenoptera, Acer negundo, Platanus acerifolia, Cercis chinensis, Toona sinensis, Lagerstroemia indica and Catalpa bungei suffered varying degrees of freezing injuries and needed to be observed in the second even third winters to decide if seedling propagation is appropriate for these species in this area. (4) The freezing injury index with properly weighted class 4 could more objectively reflect and compare freezing injuries of the different tree seedlings. The results from this study could provide a practical reference guide for seedling propagation of the 19 species in the area.