Moving Day: Tree Transplanting

In the late 1960s, architects and engineers had to pre-assemble the cubist work of art in Gary, Ind., disassemble it and then ship it in pieces to the Plaza only to reassemble it again in its final form. Although they were each installed in one giant heap during a Saturday in 1995, the trees took just as much planning and maintenance and stand just as beautifully, according to Karen Morby, an arborist at Church Landscape, Lombard, Ill.

“It’s a big space and they wanted instant big trees,” Morby said.

The Daley Plaza on W. Washington Street acts as the roof for below ground parking and office space. While the trees look like they are growing out of the ground, they are actually planted in 15-foot square vaults of soil. The 120-ton crane used to lift and lower the trees into their new homes provided a weight problem so it had to rest outside of the Plaza and reach in. To minimize other excess weight the rootballs of the trees were flattened and the vaults were filled with part new soil and part dense foam.

Even though contractors aren’t ordinarily dealing with a job like the Daley Plaza on a day-to-day basis, the precision that goes into moving a tree successfully based on its root structure, species and soil make-up is the same. Planning the tree’s relocation carefully can stop a tree’s death, which in most cases results in suffocation atop roots that had nowhere else to grow.

YOU’RE MOVING? When raised in a nursery, trees become natural candidates for transplantation. Nurserymen grow the trees in rich soil, make sure they receive the proper nutrient supplements, prune the trees regularly to develop the proper branch scaffolding, fertilize and use drip irrigation to keep the root system close to the trunk for easy mobility.

“This makes the trees more viable, producing a more fibrous root system,” said Roger Funk, vice president of the Davey Institute, a training and research consultant wing at The Davey Tree Expert Co. in Kent, Ohio.

In California, nursery trees are grown in containers that resemble planters. This makes them easy to relocate and adapt to a new location and also makes them deliverable to the Midwest and Northeast in the middle of winter when West Coast temperatures are spring-like, said Stuart Sperber, president, Valley Crest Tree Co., Calabasas, Calif.

When it comes to selected trees or trees that weren’t raised in a nursery, the odds of relocating varies on a case by case basis, Morby said.

“Trees are not pieces of furniture,” she stressed. “If it’s been in a yard for years and has never had its roots disturbed, sometimes it’s better to just cut it down than waste the money, labor, time and effort trying to move it.”

The health of a larger selected tree, usually more than 40-inches tall, needs to be assessed carefully before it is actually moved. If the tree is unhealthy, Funk said the preparation time, i.e. bringing the tree back to good health with proper watering and nutrients, could take two to three years.

It’s also a good idea to look at the tree species and how the tree regenerates its roots, insisted Thomas McLaughlin, arborist, Church Landscape, Lombard, Ill.

“It makes sense to work with the natural rhythm of the tree,” he said. “A hard, woody tree is harder to move while a softwood birch or maple is easier to move and will rebound quicker.”

The time the actual transplant is made during the year also becomes a factor.

“Deciduous trees are best moved in the winter while dormant, and evergreens tend to prefer relocating in the early spring or early fall before the start of new growth,” McLaughlin said. “The smaller the tree the better its survival rate.”

IT’S A DIRTY JOB. When a tree is taken from its home soil and moved into a soil of different composition, an interface occurs where water will resist penetration. Without water, a tree’s roots won’t grow.

“If you take a tree out of rich, good, black soil with a little clay mixed in – which helps hold the rootball together – and plunk it into a sandy site or heavy clay, it becomes an antagonist to the plant,” said Larry Hall, an arborist at Hendrickson – The Care of Trees, Wheeling, Ill. “I go by the old lawn contractor or nurseryman adage: I’d rather take a $1 tree and plug it into a $10 hole than take a $10 tree and plug it into a $1 hole.”

There’s rarely a time when the two soils will match up perfectly, so it’s important to make sure original soil is included when the hole around the rootball is filled, Hall continued. It’s also necessary to break up the new soil, creating air pockets and providing the tree’s roots with oxygen after it’s placed in the ground.

“Typically, if a tree’s roots don’t like the new soil or can’t grow in it, they will continue to grow round and round in that one spot of good soil as if they were growing in a pot,” Morby said. “Eventually, as the tree gets older, the roots will strangle it.”

Soil pH also plays a role. The availability of minerals to the tree, particularly phosphorus and micronutrients, is directly influenced by the acidity or alkalinity of the soil, i.e. its pH. Trees have certain requirements based on genetics and preexisting conditions, Funk noted. As a soil becomes more acidic, a pH, which at a neutral state is 7.0, decreases; as it becomes more alkaline, it increases.

Although there are ways to change the acidity or alkalinity of a soil type slightly by adding different ingredients, Funk said the process is too risky for a tree.

“Changing the overall make-up or chemistry of the soil for a certain tree is highly unlikely,” Funk warned. “It makes more sense to change the type of tree you’re installing.”

GETTING PACKED. When it comes to smaller trees, most contractors choose a tree spade as their transplantation weapon of choice. After becoming stabilized with a level digging apparatus on the back of a truck, each of four or five spades take turns being hydraulically driven into the ground around the rootball of the tree. The spades release water as they are forced into the soil, making the excavation easier. Watering the tree the night before will also help to make the ground more penetrable, added Jay Lacey, tree sales and relocation specialist, Southern Tree Landscape Companies, Charlotte, N.C.

“When transplanting, it’s good to have two tree spades handy, one to dig the new hole and one to dig the tree,” Lacey said. “The dirt from the new hole can plug the old hole once the tree is removed.”

Generally, a 90-inch tree spade is the largest one available in the United States and will handle a tree ranging in size from 6- to 9-inch caliper, Morby noted, adding that a common mistake made by contractors is using the wrong size tree spade for the tree they’re digging.

"Moving a 6-inch tree in a 55-inch spade is pushing it,” Morby said. “A general rule is to have a 10-inch rootball per each caliper inch of the tree. A 55-inch spade wouldn’t grasp enough of the rootball needed for a 6-inch caliper tree.”

If the spade is too big, Morby said contractors run the risk of breaking up the rootball too much because it isn’t securely held within the spade.

“When you dig up a tree, you lose between 90 to 98 percent of the roots of the plant,” Morby said. “It takes one year for every one-inch caliper tree to recover its root system. So a 10-inch caliper tree will take 10 years to recover.”

Trees larger than 10-inch caliper rely on the ball-and-burlap method of relocation. During a ball-and-burlap, contractors take on the job of the tree spade, digging around the rootball with a trencher or backhoe and forming the ball by hand, Lacey said. The dirt is then undercut so that the rootball is sitting on a type of soil pedestal. Two layers of heavy burlap are then wrapped around the ball and fastened together with staples, clamps or pinning nails.

On the West Coast, boxing trees of all sizes is prefered to using tree spades. Similar to the ball-and-burlap method, contractors will dig a large, more rectangular shape around the tree and then use pre-made box sides to work around the rootball one side at a time. The rootball is then shaved to conform to the sides of the box, said Sperber.

ON THE ROAD. Once the tree is out of the ground, maintenance and handling become crucial. The tree, after being lifted onto a flatbed truck lined with a mesh steel rack is covered with a tarp to protect it from sun, wind and obstacles that could rip off its branches, Lacey said.

“The rootball can be flattened so the tree will lie level,” he recommended.

While the tree while is out of the ground, the rootball must stay moist, Funk insisted.

"Don’t worry about too much water,” he said. “It drains so rapidly.”

Once a tree arrives at its new home and is lowered into the open hole and stabilized, any chains or ropes used around the burlapped rootball are removed.

Usually, deciduous trees grow better if not restricted by stakes or guy wires, McLaughlin pointed out. Evergreens, on the other hand, should be supported in growth for a minimum of two years after being replanted.

“Evergreens should be staked on a three-point system with earth anchors outside the ball of the tree,” he instructed. “The tie should be at or up from the tree’s center of gravity. You can protect the tree from the metal strapping of wire with a piece of hose. Keep it snug, but not too tight so that it doesn’t bite into the tree and strangle it as it grows.”

If contractors follow nurserymen’s standards as much as possible when installing trees, they can’t go wrong, Lacey said.

“And be ethical,” he added. “You can’t make a business out of transplanting with a trail of dead trees.”