Project Overview

The Environment and Ecology Building at the University of North Carolina was designed to demonstrate environmental stewardship both inside and outside its walls. Alongside the new academic facility, the university envisioned a central courtyard that would become an inviting outdoor destination for students, faculty, and visitors — a space where mature trees would eventually provide shade, comfort, and a strong connection to the surrounding landscape.

To help those trees reach their full potential beneath an active paved courtyard, 750 (2x) Silva Cells were installed in 2011 beneath the plaza. The suspended-pavement system is creating the underground growing space needed for healthy root development while supporting the hardscape above, allowing the courtyard to function as a busy campus gathering space without compromising the long-term health of its trees.

Bald Cypresses: Native Species

The university selected bald cypress (Taxodium Distichum) for the courtyard — an underused native species well adapted to North Carolina’s climate. Known for their longevity, resilience, and impressive mature size, bald cypresses have the potential to become extraordinary shade trees when provided with sufficient soil volume. In many urban settings, however, that potential is rarely realized because tree roots are confined beneath pavement.

Silva Cells offer the underground foundation these trees need to thrive. Rather than forcing the root systems into small planting pits, the suspended pavement system created generous soil volume beneath the courtyard while preserving the structural integrity of the paved surface above. By giving the trees room to establish healthy, expansive root systems from the very beginning, the project was designed not simply to plant trees — but to grow a lasting canopy.

Connected Soil Volume & Enormous Tree Growth

Nearly fifteen years after installation, the results are remarkable. The bald cypresses have grown into enormous, healthy trees that now reach the height of the adjacent building, transforming what could have been a hot, exposed courtyard into a mature, shaded landscape. Recent photographs show a thriving canopy that demonstrates exactly what can happen when urban trees receive the growing conditions they need.

A major reason for that success lies beneath the pavement. Rather than treating each tree as an isolated planting, the Silva Cell system creates one large, interconnected underground soil environment. Each tree has access to approximately 700 cubic feet of soil, but more importantly, the trees share a continuous rooting zone that allows roots to expand naturally throughout the courtyard. This connected soil strategy supports healthier root systems, encourages long-term stability, and provides the resources needed for sustained canopy growth over decades.

The benefits are felt every day above ground. The mature canopy now casts extensive shade across the courtyard, creating a cooler, more comfortable place for students to study, meet, and gather. In North Carolina’s warm climate, that shade is more than an aesthetic improvement — it contributes to student comfort, reduces heat exposure, and helps create a more resilient outdoor environment. Fifteen years after installation, the project stands as compelling evidence that investing in healthy soil below ground produces lasting benefits above it.

Sustainability in the Space Between

The spaces between buildings are often some of the most heavily traveled — and most overlooked — areas of a campus. They must balance circulation, accessibility, and hardscape (to say nothing of underground complexity, like utilities) while still creating places where people want to spend time. Successfully introducing large, healthy trees into these constrained environments is no small challenge.

At UNC, Silva Cells helped turn that in-between space into a destination in itself. By supporting a thriving tree canopy beneath a fully functional paved plaza, the system helped create a landscape that is cooler, more welcoming, and more enjoyable throughout the year. Today, the courtyard demonstrates how investing in healthy urban trees can transform everyday spaces into destinations that improve both campus life and long-term environmental resilience.