滩地杨树生长量与高程-淹水时间关系的研究

将同一滩地按高程差0.5 m设置固定样地,并根据样地高程求得12年轮伐期内各高程汛期年均淹水天数,逐年监测样地胸径、树高生长量。湖区滩地杨树各指标生长量均随滩地高程降低、淹水时间增加、地下水位升高而降低。在洞庭湖东南湖,高程在32.8 m以上、年均淹水34.8 d以下滩地可建杨树大径材工业用材林基地,31.8~31.3 m的滩地采取挖沟抬垄措施可用于杨树造林,30.8 m以下的滩地不宜用作杨树造林。

The relationship between growth increment of poplar and elevation-waterlogging time on beach land

The fixed sample plots with the same beach land were set according to the elevation difference of 0.5 m.Based on the elevations of sample plots,the average annual waterlogging days of each elevation during flood season in 12-year rotation period was observed.The diameter at breast height（DBH） and height increment of poplar in each plot were also surveyed every year.The results showed that the increment of each index of poplar decreased with decrease of beach elevation and increase of waterlogging time and groundwater level.The beach land of southeast Dongting Lake,at the elevation above 32.8 m and the average annual waterlogging duration below 34.8 d,could be used to construct the industrial timber stands base for huge wood of poplar.And the beach land at the elevation of 31.8 to 31.3 m could be used for afforestation of poplar by measures of digging trench and raising ridge.The beach land at the elevation below 30.8 m should not be used for afforestation of poplar.