Through a business acquaintance, I had the good fortune to meet with Mr. Christian Rodriguez, a company representative from Blue Drop, Inc. We met at a downtown San Diego street intersection where Blue Drop, Inc. had a contract with the City of San Diego to replace old cast iron tree grates with their new product called Safe Path.
Tree planters within pedestrian sidewalks are typically small confined spaces surrounded by concrete with lots of pedestrian traffic. Tree grates were installed around the planter pit primarily to protect people from tripping over tree roots. The grate also allowed watering to occur beneath the grate and afforded the tree a degree of root protection from pedestrian traffic.
When first installed surrounding a young tree, there is plenty of room for the tree trunk and root collar to grow and expand. Tree grate openings typically are up to 12″ in diameter.
A young tree with a two inch diameter trunk will add one inch of trunk diameter per year. The tree will outgrow the tree grate opening within a decade. Just as the tree reaches maturity and is starting to provide the maximum intended benefits, the trunk begins to lift the tree grate. Either the tree or tree grate must be replaced.
When I met Mr. Rodriguez, he showed me a downtown site where Blue Drop had installed their new Safe Path product. The product is a poured in place permeable rubberized material that levels the planter surface with the adjacent sidewalk. Water quickly infiltrates the permeable product which allows for both water and gas exchange. The tree trunk, root collar and any surface roots are safely protected by the product. As the trunk and roots enlarge, the products cracks, allowing for easy product removal and mending.
Because Safe Path is poured in place, it appears to be an ideal product to retrofit existing planter systems and especially for irregular shaped planter areas. The product provides a smooth, yet permeable surface, creating a safe environment for pedestrians while protecting tree roots and enhancing street scene aesthetics
I have no financial of special interest in Blue Drop Inc or any of their products. As a certified arborist who has provided expert witness testimony in trip and fall cases involving trees, I was interested in discovering new technologies that improve public safety around trees.
Click the link to read the full article reviewing the product. A Better Way to Protect Trees and Pedestrians