The half-century old trees growing in the median of Ewing Street received a high tech boost yesterday.

Horticultural workers from Horsfield Landscaping and Design Ltd started the process of installing Silva Cells in the ground beside them.

Albert Key, one of the owners of New York-based city landscapers Deeproot, was on the scene at Ewing Street

Mr Key, who was part of the team that invented the Silva Cells in 2007, explained: “Tree roots don’t grow in dirt, they grow in gaps of air between the dirt.”

The trees in the centre of Ewing Street grow in an especially narrow band of top soil, and their growth has been stunted as a result.

Trees growing in urban areas are often surrounded by densely compacted earth which lacks the air pockets they require.

The engineers responsible for Ewing Street have required the soil they rest on to be compacted to 95 per cent, he said.

The Silva Cell is described on its website as a modular suspended pavement system that uses soil volumes to support large tree growth. Each Silva Cell is composed of a frame and a deck. Silva Cells can be spread laterally as wide as necessary.

“This is a method that keeps the horticulturalists and the engineers happy,” he said.

The method consists of placing the cell structures in the earth that provide the support required for roads, and are filled with top soil to provide the environment the trees require to grow in a more healthy manner.

Jamie Pehkonen, an engineer with Brunel Engineering — the firm that designed the Ewing Street improvements — said of the Silva Cells: “We did it to assist with keeping the trees alive. There is very little soil here.

“This is a better environment for the trees.”

Among the places that Silva Cells have been used include the The Metropolitan Museum of Art, the Lincoln Centre, the Sundance Square in Houston and some sites used for the London Olympics.

The work should be concluded today.