Title: Comparing environmental impacts of Chinese Torreya plantations and regular forests using remote sensing

Abstract

The Chinese Torreya tree (Torreya grandis cv Merrillii) is a traditional nut tree cultivated in China for more than a thousand years. The income from the cultivation of this species for producing nuts, oil, and food has improved the local economy. Large industrial plantations of Torreya are under construction to achieve more profit, while this requires clearcutting local subtropical evergreen forests. It is necessary to evaluate the environmental impacts of land-use change at a large scale because of possible problems in sustainability. This research compared several biophysical indices from remote sensing data at a regular evergreen broadleaved forest and a nearby Torreya plantation. Our results indicated that the Torreya plantation had a lower albedo (12.43) and higher soil water storage within the surface 2 m soil layer (69.0 kg/m2/month) than the regular forest (12.64 and 57.87 kg/m2/month). The annual average Normalized Difference Vegetation Index (NDVI) was significantly higher in the regular subtropical forest landscape than in the Torreya forest landscape. Furthermore, these ecological processes’ resilience was high in the regular forest than in the Torreya plantation. The large-scale development of Torreya plantations could change local energy and hydrological processes. Environmental impacts and multiple crucial ecological services should be considered for the sustainable development of Torreya plantations in this region. Our ground studies indicate less soil carbon storage and higher soil erosion risk in the Torreya plantations than in the natural forest. These results may be helpful for local agencies to create strategies to develop sustainable local economies while conserving the natural landscape. The approach to evaluating potential environmental impacts of landscape change at a large scale may be applied in other activities (agricultural development or urbanization).