The Best Route For The Best Roots

A couple of months ago an arborist I work with told me he thought I should attend the New York State Arborists’ spring seminar that was being held in Tarrytown.

The reason? It was all about trees. Two days of nothing but trees. He said there was going to be a class and demonstration of a tool called an air spade that he was very impressed with. Plus, plant pathologist Margery Daughtrey and entomologist Dan Gilrein from Cornell University’s Long Island Horticultural Research Laboratory in Riverhead were keynote speakers.

But I’m a herbaceous perennial kind a guy, not a woody type.

For weeks I procrastinated. Did I want to go or didn’t I?

I hadn’t seen Dan and Margery in several years and this air spade stuff really had me curious. Transplanting large, mature trees by blowing the soil off the tree’s roots? There was something counterintuitive about this concept and I just couldn’t wrap my head around it to figure out how it could possibly work. But then it became very, very logical.

So I went. And yes, the word “revolutionary” was kicked around quite a bit.

Day one was talks on how the weather of the past few years has been playing havoc on our trees and shrubs. First, one of our coolest and wettest summers in decades, 2009, followed one of the hottest and driest of the past century in 2010. That alone was enough to give a woody plant whiplash. Then the diseases.

All diseases seem to be opportunistic, and in 2009 those that are known to take advantage of constantly wet soil and wet foliage did their jobs. But surprisingly, there were other pathogens that had just as much fun last summer while everything outdoors was roasting and toasting.

One common theme was that the effects of weather are rarely immediately noticeable. In fact, it can take several years to see the visible symptoms, which are often exhibited as dead branches, dieback and sadly, the death of those plants that lose the battle.

The worst news was that of the emerald ash borer (a green beetle native to Asia), which now seems to be on the precipice of destroying every single elm in the east. The better news is that there may be much better success in controlling and possibly eradicating the Asian longhorned beetle, whose spread has not quite been stopped but it has been slowed, and there is hope that in a number of locations throughout the country this insect may indeed be controllable.

There also seems to be success in controlling the hemlock wooly adelgid (a bug native to East Asia that feeds by sucking sap from hemlock trees), which has not been the killer that we’d feared. It could have been, but education programs and a quick jump on this insect, as well as alternative landscape plants, has left arborists and nurserymen optimistic.

Now to the headliner. What do you get when you take a big air compressor, a length of heavy air hose, a patented air nozzle and a directed jet of air moving at roughly 1,200 miles an hour, or twice the speed of sound? You get an air spade—a tool that can be used to transplant trees as large as 30 feet tall, without massive root damage and potentially costing a third less than other traditional forms of transplanting. But first, lets look backward a bit.

Up to this point in time there have been two basic ways of transplanting trees.

The newer of the two involves large blades that are hydraulically driven into the ground to sever the tree’s roots and pull the tree out of the ground with a soil ball intact. This is called a “tree spade.” They’ve been used for years but they are not cheap, plus they have limits on the size of the tree they can move and most important they cut much of the tree’s root system. Many roots never recover and those that do regenerate very slowly over many years.

The second and older method is the traditional digging of the tree that is then balled with burlap. The burlap is then tied with heavy twine or rope to keep the root ball intact. Balled and burlapped, or “B&B,” tree transplanting is now thought to be the most destructive method because of the extreme damage done to the root system and the high percentage of roots that are removed.

As part of our seminar, we watched as six trees from a nursery that were balled and burlapped had the soil taken away from the root balls. It was astonishing how little root mass remained but obvious that these trees, which are commonly planted in our landscapes, are destined for years of languishing followed by an untimely death. We were told that many of these trees, which should and can live 100 years, will rarely make it to 20. It was not only a condemnation of balling and burlapping but of the wholesale tree nursery industry in general.

But there was a positive note. There have been changes. But we won’t see them in the trees we buy for at least 10 years or longer.

If you need to transplant a tree from a nursery or from one property to another, the air spade may be the best route to go. The air spade works by blowing the soil away from the roots of a tree without damaging the roots. As the spade blows the soil away, the loose soil is removed and layer by layer the tool allows the operator to move deeper and further from the trunk.

Roots can be exposed several feet deep and feet to yards from the trunk, allowing a majority of the root structure to be saved instead of severed. And since the soil is either blown away or vacuumed away from the digging when the process is done, only the roots and shoot system need to be moved, not the tons of soil that might have been involved in a B&B operation.

This is where the cost savings can come in. If you’re transplanting a 30-foot larch (like I saw in the demonstration), once dug, the tree can be moved to the new planting site with a small loader instead of a huge and expensive crane. The spider web of roots is tied up for the move then laid out in the new planting hole as backfilling takes place.

The demonstration I watched was done by a somewhat petite young woman with appropriate protective gear. Within a couple of hours, she was able to remove most of the soil from the root area. Here’s how: A loader with two front forks was edged down a ramp into the dug pit; the forks slid under the small amount of remaining soil. A few of the very longest roots were pruned about 6 feet from the trunk and the tree was lifted up and out of the hole and moved to its new home about a quarter mile away.

It was simply amazing to watch the process.

Mike Furgal of Furgal Tree and Landscaping in Northboro, Massachusetts reported that he sees no other way to move trees. In the past few years, he’s moved about 200 trees between 20 and 30 feet tall with similarly impressive diameters, and he’s lost only two—and one of them was due to disease problems and not the move. That is an excellent track record and quite a recommendation for air spading as a method of transplanting. What an incredible way to keep growing.

On a personal note, on April 2, my mentor and longtime friend, Ralph Freeman, passed away. Ralph was a floriculture extension agent with Cornell Cooperative Extension of Suffolk Country in Riverhead. At a time when I was thirsting for knowledge in the world of horticulture, Ralph showed me the way. I will miss him dearly.