Modeling hydrologic responses to deforestation/forestation and climate change at multiple scales in the Southern US and China
Watershed management and restoration practices require a clear understanding of the basic eco-hydrologic processes and ecosystem responses to disturbances at multiple scales (Bruijnzeel, 2004; Scott et al., 2005). Worldwide century-long forest hydrologic research has documented that deforestation and forestation (i.e. reforestation and afforestation) can have variable impacts on watershed hydrology (Andreassian, 2004). Such impacts can be amplified by the current global climate change that results in increased air temperature and intensified precipitation. Uncertainty, speculations, and debates on the roles of forests in regulating water resources remain (Bruijnzeel, 2004; Robinsons et al. 2003). Eco-hydrologic studies are especially urgent in regions such as northern China where water stress has been severe and sciences are lacking in guiding the current large-scale vegetation-based watershed restoration campaigns (Sun et al 2006). Conflicts of human water demand and water needs by ecosystems are expected to increase dramatically in the near future due to human population growth, climate change, groundwater degradation and depletion, and increased food and fiber production demands (Sun et al. 2005). Watershed management policymaking is becoming more complex and extremely challenging given the many constrains on water and other ecosystem services that a watershed is required to offer (e.g. soil erosion control, carbon sequestration, habitat) (Jackson et al. 2005).