The Cardinal Corridor is a gateway into the Ohio Expo Center and State Fairgrounds, a site that boasts more than one million square feet of event space and occupies more than 360 acres in the heart of Columbus. In addition to being the home of the Ohio State Fair since 1886, the Expo Center also hosts over 150 events each year, bringing in well over two million attendees annually. As the point-of-entry into this major site, the Cardinal Corridor serces as the welcoming grounds for visitos
Except for a nine acre area of trees maintained by the Ohio Department of Natural Resources (ODNR), it was dominated by parking lots and asphalt, and not as welcoming a site as desired. Given the major role served by the fairgrounds to the social and economic infrastructure of the State of Ohio, Governor John Kasich wanted to create a greener, more pleasant place for visitors across the entire, 360-acre site.
For this reason they wanted to ensure that each and every tree be given access to 1,000 cubic feet of soil. Given the high volume of traffic to and on the site during fairs, however, the site did not present the option to create interconnected, open tree planters. There were a number of traffic-related factors unique to exposition centers to consider, such as presence and size of turning radii and spaces for semi-tractor trailers. These factors required a majority of the space to remain paved, making the 1,000 cubic foot goal a challenge.
The governor’s office recognized the value that trees and green space would bring to the site and was willing to make a significant investment in their planting and care in order to guarantee a long and healthy life on the site. Kasich’s team consulted with Andrew Ware, deputy director of the Ohio Department of Natural Resources, to devise a plan to bring nine large trees to the area and dramatically increase the shade along the Cardinal Corridor, creating a pedestrian friendly promenade.
The ODNR, together with the Ohio Environmental Protection Agency, the Ohio Department of Agriculture, and the Ohio Expositions commission, came to DeepRoot for consultation regarding using the Silva Cell to help them meet their goal of increasing tree cover while keeping the same amount of paving.
In addition to providing long-term soil volume to the trees, the Cells could also help to solve another problem common to expansive paved areas by servicing the drainage of stormwater off the blacktop. Site schematics that were developed by the Kestrel Design Group helped to demonstrate to the team that this solution could truly transform the fairgrounds into the park-like atmosphere they desired.
The decision was made to use Silva Cells at the fairgrounds because they would be capable of bringing the target soil volume to the trees and because their modularity was conducive to the layout of the numerous paved areas on the site. Additionally, through the installation of permeable pavers around each tree, the soil in the Cells also provides on-site stormwater management. The entire system is capable of holding up to 20,000 gallons of water that seep in through the pavers.
The ODNR was responsible for design of the site, and the Cells were installed by the Ohio department of Transportation. Altogether nine trees (a mix of hackberry, northern red oak, and honey locust) were planted in 920 frames topped with 310 decks, bringing a total soil volume of 9,000 cubic feet to the site. As quoted in The Columbus Dispatch, Ware believes that the trees should reach a height of 60 feet with a canopy spread of 70 feet, bringing much- needed shade to the fairgrounds for generations to come. Going forward, he also believes that more trees will be called for at the Expo Center. The team at the site is planning on using more Cells in tree cluster plantings as pedestrian gathering places and transportation nodes.
Average bioretention soil volume per tree: 1,022 ft3
Catchment area: 1,235 m 2 (0.3 acres)
Number of Trees: 9
Total Silva Cells: 310 decks and 920 frames
Installation Date: April 2013
Installation type: Trees
Project Designer: Ohio Dept. of Natural Resources
Contractor: Ohio Dept. Natural Resources