Tree Protection During Construction at the Florida Supreme Court
Project: Water Intrusion Project for the Florida Supreme Court
Task: Find roots so a real tree protection zone (not an estimated one) can be designed to protect four large live oaks on the grounds of the Florida Supreme Court in Tallahassee
An Air Spade was used to locate roots to establish a tree protection zone around each tree.
Trees: four live oaks (Quercus virginiana) approximately 34 to 36 inches DBH
When: January through March, 2008 and December, 2008
Architect: Hoy + Stark Architects
Location: Tallahassee, Florida
A project was begun to solve water intrusion problem at the Florida Supreme Court building in Tallahassee, Florida. Excavation was required to the foundation some 35 feet below the soil surface. A hole that deep around part of the building perimeter required a wide hole -- in some case so wide that it extended into the dripline of the protected specimen trees.
The Air Spade cuts a shallow trench around the proposed tree protection zone. A shovel and hoe are used to remove some of the loose soil from the trench.
Generally we try to protect a tree root zone at the dripline of the tree. In this case the contractor asked to be able to expand the excavation closer to the tree than the dripline. I said the only way we could do that would be to use an Air Spade and determine where the roots were really located. I started by cutting a trench around the dripline of the tree. If no roots were found, I moved toward the tree and cut another trench. I continued making concentric rings until roots were encountered.
If smaller roots are located crossing beyond the tree protection zone trench, these can be cut. If larger roots are located, then the tree protection zone is expanded whenever possible polto accommodate these larger roots.
The end result was a tree protection zone that reflected the actual location of the roots. In some cases roots were encountered at the dripline and were hand pruned at that point. In other cases no roots were encountered until I was halfway between the dripline and the tree. The end result was a tree protection zone that was slightly irregular in shape.
The Florida Supreme Court building is in the background. A back hoe is used to excavate outside the tree protection zone.
Although roots generally extend well beyond the dripline of a tree, the majority of the roots are located within the dripline. Furthermore most roots can be found in the upper 18 inches of the soil, at times roots can be found at 3 or 4 feet below the soil surface depending upon soil and site conditions. Once I established the outer limit of the roots down to a depth of 12 to 18 inches, which is the working depth of the Air Spade, I had a small backhoe remove soil to that level.
Once the tree protection has been established, the soil can be excavated and pulled back from the edge of the tree protection zone with a back hoe as required for construction. An old irrigation system has been uncovered and will eventually be replaced.
Then I would use the Air Spade to excavate down another 12 to 18 inches. If no roots were found, the backhoe would remove more soil.
I worked with the Air Spade and backhoe until we reached a depth of 36 to 48 inches where we were certain no more roots would be found. After all the work, it turned out that I only located one large root, about 4 inches in diameter, that was located below a depth of 18 inches. That root was located at about 3 feet below the soil surface.
Two St. Augustine Arborists Work on the Florida Police Officers' Memorial Oak
a news release printed in February, 2008 in the St. Augustine Record
Two St. Augustine Certified Arborists recently performed maintenance and diagnostic work on a large oak tree in front of the State Capitol Building in Tallahassee in February.
The Police Officers' Memorial Tree is located in front of the State Capitol Building in Tallahassee.
The tree is a large 36-inch diameter Southern live oak growing in the The Police Officers’ Memorial in the State Capitol Courtyard between the old Capitol building and the new high-rise Capitol building.
The live oak was beginning to push the granite slabs that surround the memorial. This granite slabs are engraved with the names of all Florida police officers who have been killed in the line of duty. Chuck Lippi, a Board Certified Master Arborist, is one of the few arborists in the state with experience in tree root diagnosis and knowledge of proper root pruning techniques thhmat will not damage the tree. The Department of Management Services hired Lippi to determine how best to remedy the problem without damaging either the granite slabs or the tree.
It was suspected that roots of the live oak were moving granite slabs.
Lippi recommended some crown cleaning and crown reduction pruning so Jason Shaw of Jason Shaw Tree Service was hired to do the pruning work while Lippi excavated around the root system. Timing was critical so all work could be finished before the legislature opened its 2008 session.
“Jason was a perfect match for this job on the Police Memorial tree,” said Lippi. He is a former deputy sheriff and currently is a reserve officer. Shaw has operated a Tree Service in St. Johns County for over 7 years and is an ISA Certified Arborist.
Jason Shaw working on the Police Officers' Memorial Tree in Tallahassee.
“It was sobering to see how many names are engraved on the memorial,” Lippi added. Lippi returned to Tallahassee a few weeks later in March to work protecting trees near a construction project on the grounds of the State Supreme Court. Lippi spent three days excavating and tracing roots of four very large live oak trees to establish the location of the tree protection fence that is to be erected prior to the beginning of construction.
The inside of the granite slabs were carefully excavated but no roots were found pushing on the slabs.
The construction project is to correct water intrusion problems that are affecting below ground floors in the Supreme Court building located across the street from the new State Capitol.
Being the Arborist for the Project, Lippi will continue to travel to Tallahassee from time to time to monitor compliance with the tree protection procedures and to monitor tree health during and following the Project.
