ABSTRACT
Viable Rooting Media ........................................................................................ 174 Rooting Volume .................................................................................................. 175 The Role of a Pavement’s Surface Course ........................................................ 177 Base Course Rooting Media .............................................................................. 180
Stone-Soil Mixture (Cornell Structural Soil) ........................................ 180 ESCS Mixtures (Arnold Air-Entrained Soil).......................................... 184 Sand Mixture (Amsterdam Tree Soil) .................................................... 187 Provisions for All Base-Course Rooting Mixtures ................................ 189
Rooting Space in Subgrade ................................................................................ 192 Special Treatment at the Tree Base .................................................................... 192 Trademarks ........................................................................................................ 194 Acknowledgments .............................................................................................. 195 References .......................................................................................................... 195
The benefits for which trees are planted, such as shading and cooling, come into being only where the trees grow long enough to realize some size (Geiger, 2003). For this reason, where trees are surrounded by pavements, the pavement structures must contribute to the habitat in which trees root and grow. The challenge is to maintain viable soil for abundant tree roots while supporting traffic load through the same structure.
