Characterization of Soil Compaction at Construction Sites and Woody Plant Response

This study was designed to quantify soil compaction occurring at construction sites and determine the effect of soil compaction on woody plant growth. Soil compaction was measured at 12 sites including residential, commercial, and new road construction. Methods of measurement included bulk density, determined with a nuclear densiometer and by the rubber balloon method, and penetrometer resistance. Bulk density in the construction zone averaged 0.50 g/cm3 (33.09lb/ft3) higher than in an adjacent undisturbed area. Bulk density readings in the construction zone were in the range that has been found to restrict growth of woody plants. Penetrometer resistance was higher in the construction zone, but this was a less reliable method of measure than bulk density for this type of site. A field study was conducted to determine the effect of compaction and puddled soil on the growth of Forsythia ovata Nakai and Cornus sericea L. Treatments included puddled soil and low, medium, and high levels of compaction. Although levels of bulk density achieved in the field plots were lower than those observed at construction sites, growth of both species was reduced by all treatments compared to the check.