Preliminary findings from measuring street tree shoot growth in two skeletal soil installations compared to tree lawn plantings

摘要

Skeletal soils include a group of designed planting media variously called structural soils, or stone matrix soils (Bassuk et al. 1998; Gamstetter 1998; Grabosky et al. 1998; Kristofferson 1998). They have been developed to improve street tree establishment and growth in paved situations. Before pavement is laid, the subgrade and base layers of a pavement section must be compacted to meet engineers' specifications for load-bearing. This often leads to soils that are too dense for root penetration.Skeletal soils, when designed correctly, create a rigid matrix with large pores to allow root growth without sacrificing soil load-bearing capacity. The discussion about use of skeletal soils, their practicality, and their long-term efficacy has grown over several years. However, there is little long-term data on skeletal soil used in actual pavement systems. Toward that end, trees established in one type of skeletal soil profile (CU Structural Soil~(R)) are being monitored annually to track tree growthresponse. The chosen installations have trees growing in paved systems and lawn areas for comparison, and replicates were chosen to minimize influence from confounding variables such as levels of use, sunlight, wind, and adjacent building height. This technical note presents preliminary data on two sites being monitored. The two projects were installed in fall 1997.The first project was located on Lorimer Street adjacent to McCarren Park in Brooklyn, New York, U.S. The second project was part of a NewYork State Department of Transportation street renovation in Ithaca, New York.