Vegetation restoration projects in the Loess Plateau have improved the vegetation coverage in this region. However, factors like afforestation species selection, site conditions, initial planting density, and climate change lead to soil desiccation and afforestation degradation.
Tree-ring climate/environment records can provide long-term data supports for in-depth understanding of plant-water relationships.
Using dendroecology method and Climwin model, a research team led by Prof. XIAO Shengchun from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences (CAS) examined the growth response of planted shrub Hippophae rhamnoides on different slopes and scattered distributed natural shrub Caragana opulens to climate in the western Loess Plateau.
Related results were published in Ecological Indicators.
The researchers collected annual ring samples of two xeric shrub species in western Loess Plateau and investigated data on shrub growth indicators and soil water content. They also tested the hypothesis that radial growth of xeric shrub may be affected by variations on different slopes and species.
The results showed that insufficient precipitation from April to June was the main limiting factor for the growth of planted H. rhamnoides in the western Loess Plateau.
On different slopes, the planted H. rhamnoides was susceptible limited by precipitation and drought stress on shady slopes than sunny slopes, planting density was the main reason for the above phenomenon.
"Sufficient precipitation and moderate initial planting density may mitigate the limiting of drought on plantations growth," said Prof. XIAO.
Research results suggested that the natural shrub C. opulens was less affected by precipitation and drought stress compared to the planted H. rhamnoides, and might be promoted appropriately as a suitable afforestation species.
"The vegetation restoration construction in the near future should fully consider the slope aspects, planting density, as well as the limiting factors and time on growth of plantations species," said Prof. XIAO.
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