How do you move a tree that sits 50' tall, measures 75' across in its canopy spread, and weighs 250,000 lbs., so that it can continue living as it has for the last century? And then, how do you replicate that 14 times?
"Using air!" is the answer The University of Texas at Austin (UT Austin), Environmental Design Inc. (EDI), Bury Civil Engineers, and a team of Sasaki landscape architects came to. We teamed up to move gigantic trees as an early step in implementing a new master plan for the Dell Medical School campus.
As a contributing author of the new national sustainability rating system for The Sustainable Sites Initiative (SITES™) program, UT demonstrates consistent commitment to sustainable building on its campuses. And once again, UT took great pains to ensure that it preserves as many of the much-loved Live Oak trees as possible in this latest campus development initiative.
The trees are not only beloved to students, alumni, and administrators as beautiful emblematic features of the school's landscape but also for the shade they provide in the Texan heat and the many benefits they deliver to the ecosystem at large. They bolster the ecosystem by contributing to local climate regulation, air and water cleansing, erosion and sediment control, habitat functions, and human health and well-being. It's an important and worthwhile investment that will continue to pay off for years to come.
The team chose the 14 trees to move from a list of approximately 50 trees based on the following criteria:
• Ability to survive the move
• Benefit to the ecosystem
• Aesthetic quality
Moving these giant trees is no simple task. Once identified, the team had to carefully plan where each tree could move. The campus is bifurcated by a creek and none of the bridges spanning the creek can support the massive weight of a tree-crossing so trees native to each side of the creek had to stay on their respective sides. The team strategized movement to keep the wide spread of branches from wreaking havoc on cable lines and lighting. They also tried to keep from moving trees across long distances, given the difficulty of the moving process:
First, the critical root mass needed to support the life of the tree must be identified before the roots can be pruned. To minimize trauma, root pruning, preparatory watering, and enriching with nutrients occurs months in advance of the move. The new site must then be dug cleanly to receive the tree. Prior to moving, a structure of steel pipes is fashioned beneath the tree to create a rigid, supportive platform. On moving day, the tree is rolled onto large air-filled tubes, which are hydraulic-controlled to keep the whole tree level. Excavators then push or pull the platform to roll the tree to its new location, where it is planted in prepared soil. In the year after a tree's move, EDI will closely monitor each tree, providing plenty of regular hand-watering.
To date, the team has moved 7 of 14 gigantic trees successfully. EDI boasts a consistently high survival rate for its trees and expect all 14 trees to make smooth transitions to their new homes.
To watch the move in action, access UT Austin's video here!
This is not Sasaki's first project saving trees—and we certainly hope it is not the last! See how we helped to activate the landscape at The Oklahoma City National Memorial and Museum, which features the Survivor Tree, a very large and very old Elm that survived the 1995 bombing attack and remains an important symbol of resilience for the city.
Photos captured on-site
A large Live Oak sits on its pipe platform, ready to be moved.
The team prepares to push one of the trees to its new home.
Trees on either side of the creek have to stay on their side of the creek.
Their gigantic scale becomes apparent when seen next to buildings.