Impacts on aesthetics and recreational opportunities from solarทpower are less clear. Recent legislation introduced in California placed large tracts of land out-of-bounds for solar energy plants, partly due to recreational and visual impacts, and partly for ecological concerns [59]. The visual and recreational impacts are difficult, to quantify but much progress has been made by the U.S. Forest Service over the past decades toward appraising visual resources during land development [25]. A similar approach could be used for recreational resources. Regarding recreational resources, note that a switch to solar power would decrease mercury deposition on lakes and rivers, thereby improving their utility for fishing and recreation. Mountaintop mining could also be reduced or displaced by deployment of large-scale solar power, thereby opening vast amounts of highland forest to recreational opportunity.