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

Abstract

It is important to evaluate the environmental impact of land-use change before deciding on its development because of possible problems in sustainability. 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 has improved the local economy in southeastern China. To increase nuts production, large industrial plantations of Torreya are under construction, which require clear-cutting local subtropical evergreen forests. In this study, several biophysical indices from remote sensing data at a regular evergreen broadleaved forest and a nearby Torreya plantation were compared. The results indicated that the Torreya plantation had a significantly lower albedo (12.43 ± 0.15%) and higher soil water storage within surface 2-m layer (69.0 ± 2.24 kg/m2/month) than the regular forest (12.64 ± 0.14% and 57.87 ± 1.81 kg/m2/month). The annual average Normalized Difference Vegetation Index (NDVI) was significantly higher at the regular forest landscape than at the Torreya forest landscape. Except for NDVI, the resilience of these ecological processes was high in the regular evergreen broadleaved forest than in the Torreya plantation. The development of Torreya plantations at a large scale could alter local energy and hydrological processes. Environmental impacts and multiple ecological services should be considered for the sustainable development of Torreya plantations in this region. This study may provide an approach to evaluating potential environmental impacts for landscape change at large scales. Further research by ground observation and studies on ecological processes at different scales should be conducted. Our results may be helpful for relevant agencies to create strategies to better develop local economies and conserve the natural landscape.