Dendroecological assessment of Korshinsk peashrub (Caragana korshinskii Kom.) from the perspective of interactions among growth, climate, and topography in the western Loess Plateau, China

Dendroecology is a useful tool to provide insights into the growth of woody plants and their response to climate change and topographical factors, since the results can provide guidance for the management of artificial forests. Using dendrochronological methods, we examined the relationships between slope aspect, climatic variation, and radial growth of Korshinsk peashrub (Caragana korshinskii Kom.), a primary shrub species used in afforestation in arid and semi-arid regions of the Loess Plateau, in northwestern China. Mean May temperature is the primary factor that limits radial growth at all study sites, followed by September and October precipitation at the shady and sunny sites. Our surveys of canopy area, shrub height, number of branches and average ring width showed that, except for the number of branches, the value on semi-shady slopes was larger than those on shady and sunny slopes. No evidence of soil desiccation was found, and the best water status occurred on semi-shady slopes at depth from 10 to 60 cm within the 1.8 m profile. The age-related average ring width curves indicate that radial growth increased to about 4 years of age, declined rapidly until 8 years of age, and then stabilized. Our results suggest that Korshinsk peashrub is a suitable species for afforestation in the western Loess Plateau, especially on the semi-shady slopes, and that a suitable age to begin branch coppicing is around 8 to 10 years. However, shrub density should be maintained at low levels (around 5000 shrubs per hectare).