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Posts Tagged ‘Plant management’

Last week I drove past the Paulownias I wrote about in 2009, and realized that they deserved another blog post.  In the four years since that post, all three trees have shot up.  

I kept trying to shoot an image with the two paired trees in it, minus the utility lines, but it wasn’t doable without risking life and limb.  The trees have grown higher than the house and the utility lines, and have easily tripled (at least) in size.

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Two paulownias planted four years ago now shade almost the entire front yard.

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The smaller of the two trees measures perhaps 12″ DBH.  The once-sunny walkway is now almost entirely shaded.

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It’s a little tricky to see, but the right-hand tree is larger than the one to the left.  Directly behind it stands a large Japanese maple; in the 2009 post you can see the maple’s fall color, and compare its trunk size to the now-towering Paulownia’s. 

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Air-tool transplanting is continuing here in Massachusetts; while it hasn’t yet become commonplace, arborists in this part of the world are conversant with the techniques, and some firms have been routinely been moving trees bare-root for the last few years.  Leahy Landscaping of Lynn, MA, has a team of transplanters, led by Mass. Certified Arborist Bob Dobias.  Bob recently sent me some photos of a project his crew carried out this past summer; they moved a beautiful 14′ Fastigiate Beech in Salem with air.  They relocated the tree from a location right next to a building to a spot further out on the property, where it can now grow to its full potential.  Here are the pix Bob sent:

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This tree has been growing nicely next to a condo entry, but was likely planted there when it was a much smaller specimen.

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Bob has exposed the topmost roots, and is working his way underneath the root mass.  Note that he’s wearing ear protection and has dust barriers set up around the work area.

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Fastigiate Beech is a narrow tree, and while a blowout to the dripline frees most of the roots, some root mass still had to be cut.  Bob reports that his crew cut one root that was growing under the driveway.

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Nice root mass on this tree.  The time had arrived for this tree to be transplanted; notice that the roots to the right are shorter and have been redirected down by the presence of the building wall.  A tree that grows for too long this close to a wall might not be as readily moved as this one — not because it can’t be dug out, but because the root mass has grown too asymmetrically for the tree to stand well away from the wall.

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The Beech being introduced to its new home.  According to Bob, the crew could have lifted the tree by hand, but decided to use the machine to minimize hazards to it.  For the actual move, they tied the tree to the forks; this shot, it has been untied and is being guided into the planting hole.

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And from a different angle.  The hole receiving it could be a bit wider, to make the backfilling and mudding in easier, especially as there are no obstructions around it.

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With the tree placed in its new home and backfilled, the crew waters and muds it in.  Leahy added better loam for backfill, and secured the tree with duckbills, to insure stability while it grows into the new location.

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Proud Leahy crew and Fastigiate Beech.  The Beech should now be able to grow a little fuller both above and below ground on the side that had faced the building.  The transplant operation took about six hours from start to finish.

Bob reports that the tree has experienced some stress from the move, but he expects it will equilibrate crown and root growth and leaf out well next year.  We’ll keep an eye out for more pix next year, to check its progress.

Fastigiate Beech moved by:

Leahy Landscaping, Lynn, MA

Arborist in charge:  Bob Dobias, MCA

Crew:  Alfredo Esteban, Shane Corcoran, Greg Beatrice

 

 

 

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This year’s New England Grows featured a talk by Jim Flott, who discussed the bare-root transplanting of large trees.  Jim talked about root-washing, something he has studied, practiced, and taught, on his own and with the late Bonnie Appleton of Virginia Tech.  He spoke about the history of bare-root transplanting — until the middle of the 1900s bare-rooting was the primary way to transplant trees — and about bare-rooting with air tools.  It was a great presentation; this abstract by Flott and Appleton covers a lot of the territory Jim discussed, and it’s worth a read.

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Bare-root transplant with air tools — 12″ caliper London Plane tree, moved in late July 2009 in Wellesley, MA.

After Jim’s talk in one of the large auditoriums, he moved to a smaller room for an ‘Speaker Unplugged’ session, where people could ask him questions and exchange information.   As had happened at New England Grows three years ago, when Matt Foti discussed bare-root transplanting with air tools, someone asked about the effects of bare-root transplanting on a tree’s taproot.

How does bare-root transplant affect a taprooted tree?  The answer, both from Jim and from Matt, is that taproots are rarely an issue.

A taproot typically forms when a seed germinates; the baby taproot emerges first from the seed, growing down and anchoring the seed in the soil.  Next, the cotyledon shoot emerges and grows upward.  As the cotyledon starts to photosynthesize, root hairs branch out from the taproot, and the root volume grows and spreads.  The depth of roots is determined in part by available moisture and in part by soil type.  Typically, organic soils — which hold water and allow good cation exchange — rest at the top of the soil profile; mineral soils underlie the organic horizons, and are much less hospitable to roots.  Here in New England soils may be quite thin, and are often underlain with rock.

So taproots here will serve that useful anchoring function early in a tree’s life, but soil conditions and the plant’s own tendencies will promote the outward, rather than the downward growth of a tree.  In fact, the overall growth of tree roots tends to be outward, rather than down; the old image of a root mass volume and form mirroring a tree’s crown volume and form has been proven false.

We know that trees tend to develop their roots in the top 18″ of soil; the larger the tree, the deeper that zone may go, but typically it extends no more than 3 or 4 feet below grade.  Some thick roots on very large trees may extend vertically down in this zone, if soil conditions permit, but many more run horizontally away from the tree’s trunk.  The anchoring function of that original taproot, if it remains, is replaced by the anchoring provided by a much broader and more extensive mass of roots growing out and (to a much less extent) down.

As I wrote in an earlier post (with thanks to Linda Chalker-Scott for its title):

It’s helpful to keep in mind another factor when thinking about taproots and transplanting trees.  More often than not, a large tree being transplanted was planted out years earlier as a B&B plant, or possibly moved into place with a tree spade.  Both methods would have cut any taproot in the initial planting.  When the end of a root is cut, the tree tends to send shoots out from just above the cut end.  In a vertically oriented root, the new shoots are apt to extend horizontally from the cut end, and feeder roots would similarly extend out horizontally.  The situation may well be different for a tree that has grown from seed in one place, that someone now wants to transplant bare root, but for most landscape trees the taproot issue is moot — whatever taproot may have existed when the tree seed germinated has already been cut, and the tree has adjusted for its loss.


A carrot grows downward, with rootlets out to the side and foliage above ground. A tree is not a carrot. Photo by obenson in Flickr.

This beech tree was moved last fall, having been transplanted once about 20 years ago. See how the root mass extends far out horizontally, with a relatively shallow depth.

This is one of the thickest roots extending vertically from the beech’s trunk. This root was cut in the earlier (20 years previous) transplant; note the resultant root growth just above the cut.

 

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Last fall Matt Foti‘s excellent crew moved a mature Katsura tree (Cercidiphyllum japonicum) on the UMass campus in Amherst.  Jim Flott showed one photo of the tree in his New England Grows presentation last week, to illustrate the breadth of a root mass; take a look here to see what it looked like during and after the soil blowoff.

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Notice the trench dug around the entire root mass.  Typically, the crew uses a line tied to the trunk to swing and mark the edge of trench at the tree’s dripline.  If really significant roots appear once the first buckets of soil have been dug, the crew can decide to shift the trench edge outward to save more roots in the blowoff.  Alternatively, if no roots are found that far out from the trunk, the excavator can dig closer in to the trunk until roots appear, and the trench placed at that diameter out from the trunk.

Plywood is visible to the left of the photo; soil is blown into the trench for removal, but plenty of soil and dust fly around, and the plywood barriers help contain it, and keep the surrounding site cleaner.  The soil pile behind the plywood is what has been excavated to form the trench.

According to Matt, this tree is 20″ dbh, with a 22-24′ wide root mass.  The crew blew it off in one day, and moved it about 2,000′ away the next day.

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One of the benefits of air tool work like this is the fact that roots become visible, and it becomes clear how a tree grows below the soil surface.  The roots here obviously cover a huge area, and their density and branching suggest resilience and vitality.

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Notice how much soil remains around the base of the tree.  Leaving a slug of soil makes it easier to place the tree level in its new location, at the correct depth.  The crew usually blows soil first from the root tips, and works back toward the trunk, always blowing soil toward the trench.  The circular track around the tree’s trunk was made by the crew toward the end of the blowout, as they worked their way around the tree.  Pigtails of roots are held off the ground with lines tied back to tree branches well-padded with burlap.

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Katsura en route to its new home on the UMass campus.  Interesting to note how dense and finely branched the tree’s crown is, especially in light of how dense and finely branched the root system is.

Stay tuned for more photos of this tree in the next few months, when we get some followup shots after it has leafed out.

Location:  University of Massachusetts, Amherst, MA

Moved by:  Matthew R. Foti Landscape & Tree Service, Inc.

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It was just over a year ago that an ecologist and ISA-Certified Arborist, Lisa Montana, contacted me from AECOM, the global architectural/engineering giant.  She works in New York City, and is involved on projects that require utility trenching under sidewalks and around the roots of adjacent street trees.  When her project sites have contaminated soils, excavation must take place with shovels and bars, the old approach to bare-rooting plants.  On sites with clean soils, the workers use air tools, which let them remove soil and preserve important tree roots.

Lisa kindly sent me some photos of air-tool trenching projects she has overseen, and with my apologies to her for the long delay, I’m posting them here.  Take a look, and note how persistent and vigorous those critical roots are even underneath concrete pavement.

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This one is a 26″ dbh Honey Locust.

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This astonishing root mass belongs to a 28″ dbh Oak.

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These roots come from an enthusiastic 29″ dbh Norway Maple that needs the rooting area in the lawn beyond the sidewalk.

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This final photo shows a 32″ dbh London Plane whose roots are seeking moisture in the bed beyond the fence.

It appears as if each of these trees is reaching underground toward open ground, where adequate moisture and air can be found to sustain them.  I have been mulling over these photos for some time, and especially since Hurricane Sandy, when so many uprooted New York street trees appeared to have root masses that conformed to the bar-like shape of their planting spaces.  I wonder if those root masses had been cut at some point, as is often done for the reconstruction of a sidewalk or for utility work done in a less sensitive way than AECOMM’s methods.

Thanks, Lisa, for sharing these photos, and giving us a peek at what’s going on under some sidewalks.

Location:  New York City

Arborist In Charge:  Lisa Montana, AECOMM

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Elm trees are known for their toughness in urban conditions; it’s why so many were planted in the American landscape.  For speed of growth, beauty of form, and wholehearted commitment to growing in all sorts of conditions, almost nothing beats Ulmus americana.  The elm’s Achille’s Heel, of course, is Dutch Elm Disease, which decimated the population of them through the twentieth century.  For the last half of the twentieth century, it was quite unusual to see American elms planted anywhere; they almost entirely disappeared from the market.

It wasn’t impossible to find them, though, and scientists and a few growers continued to work on developing disease-resistant strains of this majestic tree.  The Elm Research Institute grew and distributed clones of elms it believed showed resistance, and in the 1990s Dr. Denny Townsend, a geneticist with the National Arboretum, released two of the first DED-resistant cultivars of American elm, called ‘New Harmony’ and ‘Valley Forge’.  Bit by bit the American elm began to reappear in the landscape.

I was part of the design team for the streetscape restoration of Boston’s downtown area during the Big Dig design and construction phases.  We selected the National Arboretum elm cultivars, among a range of trees, to help fill out the planting palette for what became the Rose Kennedy Greenway.  So far, the trees have been doing swimmingly.

Last week Matt Foti’s crew spent a few days on the Greenway moving a collection of trees bare root from one of the parcels near Quincy Market.  The Rose Kennedy Greenway Conservancy will be building a permanent carousel on that parcel, and they wanted to save and reuse the trees that had been growing where the carousel will be placed.  Matt called to tell me about the work, which involved moving some red maples and some American elms that had been in the ground for the last 6-7 years.

The red maples, about 6″ in diameter, moved quite easily; their roots had readily broken out of the original root balls and grown nicely out into the planting medium.  Blowing them out was a simple process.

The American elms, however, had gargantuan root systems that seemed to go on forever.  Root growth was thick and profuse, and the crew had to keep blowing further and further out, and further and further under the root plate.  Here are photos that Matt sent of the elm roots:

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Tremendous root mass on an elm that had been planted only 6-7 years earlier.

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One elm getting lifted out of its planting hole.  Sinker roots had to be blown off; though the tunnel top is three feet below the surface, it appears that the roots on this tree had grown down to the concrete surface. Note the clean cuts on roots that had to be severed.

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…and go back to school for a day.  If anyone in the Massachusetts woody-plants world has not seen the latest in tree- and shrub-planting techniques, here’s your chance:  on September 27, Rolf Briggs and Matt Foti will be giving a workshop entitled At The Root:  Air Tools Workshop at the New England Wild Flower Society’s Garden In The Woods.   Matt and Rolf will discuss and show the best techniques for planting trees and shrubs fresh from the nursery (air tools not necessary for this), as well as how to use air tools to trench under trees, decompact soil, and transplant trees.

I have my reasons to promote this workshop (and it’s next-day partner, At The Root: Understanding and Managing Healthy Soils), and they center on the fact that every planting season I find myself coaching laborers on how to deal with the root balls of plants that we’re planting on my job sites.  The boss, not knowing or having taught his laborers the proper planting techniques, usually has priced the work based on a quick  installation (dig the hole, stick the plant in, cover up the root ball, basket, and burlap), and the laborers, knowing only the quick and dirty method, look sideways at me as I show them what I want them to do.  The guys do the work the way I want it, but really, the process would go much more smoothly, and more landscapes would establish and grow in better, if everyone knew , priced, and carried out the work in what are considered the most plant-friendly ways.

Some of the most effective tools available to see what can be considered plant-friendly, and to work in soil crowded with roots, are pneumatic air tools.  I believe that Rolf and Matt will be transplanting a tree bare-root, using air, which will afford workshop attendees a chance to see what a tree’s roots really look like when the soil is blown away.  It’s an experience that can change how anyone working with plants understands how a plant grows and anchors itself, and for that alone this workshop is worth attending.

Watering in a newly planted tree-form Taxus from Weston Nurseries.

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