Restoration technological for Caragana intermedia plantation in alpine sandy land

To explore the most suitable restoration techniques for Caragana intermedia plantations in alpine sandy land, this study was conducted in different ages of C. intermedia plantations in sandy land of Gonghe Basin, Qinghai Province. Three stumping treatments were set up in all plantations: alternate stumping, alternate 2 lines stumping 1 line and delta-shaped stumping, the no stumping plantations were used as the control. The growth status indicators of the newly grown shrubbery were studied. The results showed that the biomass and leaf area of the new shrubbery with all stumping treatments were significantly higher than those of the current-year shoots of no stumping shrub (P < 0.05). The biomass of the new shrub increased by about 2～13 times and the leaf area increased by about 0.7-3.1 times after the stumping measures, the biomass and leaf area of the current-year shoots of the no stumping shrub were significantly positively correlated with the height, basal diameter, crown and biomass of the newly grown shrubbery after stumping. The Redundancy Analysis (RDA) indicated that the explanation degree of plantation age and stubble measures on the growth index of new shrub was 23.10 % and 68.99 %, and the biomass of the newly grown shrubbery was negatively correlated with the plantation age. The results of Principal Component Analysis (PCA) showed that the comprehensive evaluation order of various stubble measures was alternate stumping > triangle shape stumping > alternate two lines stumping one line. In conclusion, the restoration technology dominated by interlaced stubble can effectively improve the productivity of Caragana intermedia plantation in alpine sandy land, and it is better to implement stumping management measures before the plantation begins to degrade.