During a 3-year construction project at SMU, we safeguarded 11 Live Oaks, each 75 years old and valued at over a million dollars collectively. Ensuring these trees remained unharmed was vital due to their historical and aesthetic significance. They are the focal point of the college campus’ entrance.

In construction zones, trees are often overlooked, seen merely as circles on a map. Our challenge was to protect these living organisms from heavy equipment like cranes, 18-wheelers, and bulldozers that could damage the trees’ trunks, bark, canopies, and root systems. We began by installing fences around each tree, which forced the vehicles and equipment away from the trees.

To protect the root systems’ drip lines from vehicles weighing up to 100,000 lbs, we created a temporary road. If the heavy equipment were to constantly drive over these essential root systems for years, the soil would have started to become tightly compacted. The compaction would cut off essential nutrients and oxygen, ultimately killing the trees.

The base of our temporary road, built to prevent soil compaction, consisted of 10 inches of mulch with a protective fabric underlayment. In addition to providing a pliable base layer to help absorb the weight of heavy equipment, the mulch base can be recycled for use in the landscape after construction danger has passed.

Construction mats supporting up to 80 tons and a gravel top layer were installed on the temporary road. This setup ensured even weight distribution, preserving the soil’s integrity and the trees’ health. With the temporary road in place, the weight of the construction equipment could be evenly distributed, preventing soil compaction.

With the roots shielded from compaction, we initiated an irrigation program and provided regular arborist assessments and treatments. These included air spading for aeration, deep root fertilization, and injections to enhance natural defenses and suppress diseases.

A further challenge arose when utility lines were installed. Before the construction crew installed the utility line, we first used an air spade tool to loosen the compacted soil with its high-pressurized compressed air.  

The hardened soil that had been lying beneath the concrete for years was now loose and soft, allowing us to prune back any roots that were in the way of the utility line’s pathway. Since roots of similar tree species are grafted together underground, like one big spider web, we sealed every pruned root with Lac Balsam, ensuring that the grafted roots would not become wounded and carry Oak Wilt from one root to another.  

Oak Wilt, spread by the Nitidulidae beetle, threatens the water system of trees, leading to canopy death. Despite several campus Oaks being infected in the past, our proactive measures and frequent assessments ensured these Live Oaks remained healthy.

To protect the foliage, we regularly hosed down the canopies to remove construction dust that could block photosynthesis. We also pruned damaged or dead limbs and preemptively trimmed branches that might be hit by equipment, reducing the trees’ risk of failure.

An unexpected challenge occurred when contractors removed all of our protective measures for a ribbon-cutting ceremony. This included the tree barricades, irrigation systems, and the temporary road. This led to trucks parking under trees and equipment damaging root zones and limbs. We immediately halted construction after the ceremony, reinstated safety provisions, and tended to the damaged trees.

Our swift actions prevented further harm, allowing construction to safely resume around the trees. Throughout the project, we nurtured the Live Oaks, ensuring their continued health and success despite the surrounding construction activities.