Stem radial growth indicate the options of species,topography and stand management for artificial forests in the western Loess Plateau,China

摘要

An understanding of the differences in artificial forest between tree species,slope aspects,and management options in arid environments is fundamentally important for efficient management of these artificial systems;however,few studies have quantified the spatial and temporal differences in stem radial growth of trees in the arid western Loess Plateau of China.Using dendrochronology,we assessed the growth of three woody species(the native shrub Reaumuria soongorica,the exotic shrub Tamarix ramosissima and tree Platycladus orientalis)by measuring the annual stem radial increment.We also describe the long-term growth trends and responses to climatic factors on slopes with different aspects during periods with and without irrigation.We found that precipitation during the main growing season was significantly positively correlated with ring growth for all three species and both slope aspects.In addition,supplemental water(e.g.,irrigation,rainwater harvesting)greatly relieved drought stress and promoted radial growth.Our results suggest that as the main afforestation species in the Loess Plateau used for soil and water conservation,P.orientalis is more suitable than T.ramosissima under rain-fed conditions.However,a landscape that combined a tree(P.orientalis)with a shrub(R.soongorica)and grassland appears likely to represent the best means of ecological restoration in the arid western Loess Plateau.