Natural Regeneration of Chinese Sweet gum (Liquidambar formasana) Population in Southeast Hilly Region of Hubei Province
鄂东南低山丘陵区枫香种群的天然更新方式与特征

Chinese sweet gum (Liquidambar formasana) is a subdominant tree in the forest of a southeast hilly region in Hubei province. A stable sweet gum population is considered as a key component to the regional environment; thus, a clear understanding of its natural regeneration is important to vegetation management and regional economy. To study the role of sweet gum natural regeneration, we surveyed the Chinese sweet gum forest and the pine (Pinus massoniana)-Chinese sweet gum mixed fores t in a southeast hilly region in Hubei province; to explore the growth and dynamics of sprouting, we surveyed sprouts of sweet gum stumps that were logged 1 year, 7 and 30 years ago. The results indicated that individuals developed from seeds, and stump-sprouts coexisted in sweet gum populations, but the ratio of seedlings to sprouts differed between the two forest types. All sprouts could be classified into two groups: one was from the base of seedlings, which could be a response to natural selection, and the other was from stumps left by cutting, which was a response to disafforestation. Self-thinning played an important role during seedling survival: one or two sprout(s) could survive and eventually reach the canopy. In general, sprouts possessed a greater height growth rate than did seedlings. In conclusion, the coexistence of seedling regeneration and sprout regeneration maintained the population size of Chinese sweet gum in the southeast hilly region in Hubei province.