T

he owners of Alden Lane Nursery constructed a new retail building and entrance area in 2001. Two large 300-year old oak trees needed to be preserved and careful planning of the surrounding pavement was of utmost importance to the owners.

The pavement had to allow air and water reaching the roots while supporting car and pedestrian traffic. The choice was the SF-Rima™ permeable paving stone system, which leads rainwater to the roots and allowing for air infiltration. One of the large trees is centered at the circular entrance area.

The permeable pavement was built outward from the trees drip line to avoid damaging the roots. The base consisted of 6 inches of ¾ to ½ inches compacted crushed stone with one inch of ¼ in. to No. 10 aggregate for the bedding course. After compaction, the same bedding material was used to fill the joints and the pavement was compacted again. The other dignified oak tree is in the pedestrian courtyard at the new store building.

A large unpaved area surrounds the tree base. SF-Rima™ stones were placed several inches above the tree base soil on the preexisting root zone without excavation. The joints are filled with open-graded aggregate.