5Costanza R, d'Arge R, de Groot R, et al. The value of the world's eco- system services and natural capital [ J ]. nature, 1997,387 ( 6630 ) : 253 - 260.
6Bishop K. Assessing the benefits of community forests :an evaluation of the recreational use benefits of two urban fringe woodlands [ J ]. Journal of environmental planning and management, 1992,35 ( 1 ) :63 - 76.
7Bolund P, Hunhammar S. Ecosystem services in urban areas[ J] . Eco- logical economics, 1999,29 (2) :293 - 301.
