Handel, S.N., G.R. Robinson, W.F.J. Parsons and J.H. Mattei
Closed or abandoned landfills represent significant land areas, often in or near urban centers, that are potential sites for ecological restoration of native woodlands. But current guidelines in many jurisdictions do not allow for the installation of trees or shrubs above landfill clay caps, although these plants have many environmental, functional, and aesthetic advantages, including a rapid start to community succession. Typical closure procedures for capped landfills include only a grass cover to control moisture infiltration and impede soil erosion. The main concern that limits the application of a woody cover to a closed landfill is that roots may penetrate and weaken the clay cap. As part of a comprehensive experimental program on woodland restoration, we installed 22 tree and shrub species on Staten Island, New York (the Fresh Kills Sanitary Landfill). We found no evidence that roots of the transplanted woody plants penetrate caps used on these landfills.