A Tale of Two Trees

A Tale of Two Trees

A Tale of Two Trees

Ulmus Parvifolia planted in Stratacell system just over 12 months ago.

In February 2011, two different tree pits were planted at the same time with the same tree species (Chinese Elm) at the Ashfield Civic Centre in Sydney, Australia. The tree in the centre forecourt was planted using the Stratacell™ suspended pavement system while the two trees near the sidewalk were planted in structural soil (rock/soil matrix).

Over a year later, the canopy density of the tree planted using the Stratacell system (suspended pavement – middle and far left images) is significantly thicker than the one on structural soil (rock/soil – shown on far right).

These early results from the Ashfield project are well supported by a fascinating study conducted by E. Thomas Smiley, Lisa Calfee, Bruce Fraedrich and Emma Smiley, comparing structural and noncompacted soils for trees surrounded by pavement.

In the 2006 study, Snowgoose cherry and Bosque lacebark elm were planted into five different soil treatment options under pavement, including compacted soil, gravel/soil mixture, Stalite, Stalite/soil mixture, and noncompacted soil.

After 14 months, the study found that there was more trunk diameter growth with the noncompacted treatment than the other treatments. There was also more twig growth, higher relative chlorophyll rating and more root growth compared to all the other systems.

The comparison showed that the foliar rating with the suspended pavement system was significantly better. Aside from this, “the mean SPAD reading of foliar colour was also significantly higher” as well as “the root length at the rhizotrons”.

The study’s conclusions state that “suspended pavement over noncompacted soils provided the greatest amount of tree growth and health and should be considered when designing urban planting sites for trees”.

Citygreen® Stratacell system is an engineered load bearing matrix that supports pavement and traffic load, while providing in excess of 90% uncompacted soil by volume.

Suspended pavement systems, especially those incorporating the soil cell technology, are fast becoming the preferred choice for successful urban tree pit design.

Share with us your experience on trees planted in structural soil and suspended pavement systems.

“Great customer service, quick response times and a very in depth QA system with constant support.”

- Laura Wiesenekker, Project Engineer, Densford Civil -

“Citygreen is a very professional  business, and I found everything was great in terms of deliveries, product supply and information. It was all forthcoming and helped us to complete the project.”

- Keith Burns, Architect/Designer, Keith Burns Architect -

“Citygreen offered training and invaluable technical assistance during the works.”

- James Callan, Estimating Manager, Complex Co Pty Ltd -

“Our experience, in working with a Citygreen Design Studio was second to none. We found responses from the design studio to be very timely, and technically thorough. We went backwards and forwards a number of times, looking at different iterations of the design and, nothing was too much trouble to examine and explore different possibilities. I would highly recommend the Citygreen Design Studio to any future client considering using your services.”

- Sandra Smith, Principal Landscape Architect, City Of Monash -

“We are big on compliance on all projects, and the fact that their SmartCertify cloud platform covers all bases, and supports their 20 year warranties, is critical – especially that these pits are being installed under roadways and footpaths.”

- Johny Purkaystha, Civil Program Engineer, Central Coast Council -

"I reviewed all the previous projects that we have installed in the past couple years using your product and I can happily report back that we have 0% mortality in the soil cells, which is incredible!"

- Brendan Wilton, CEO, Trim Landscaping, Bedford, Canada -