Feeds:
Posts
Comments

Posts Tagged ‘Roots’

Last February I wrote about the bare-root transplant of a large Katsura tree (Cercidophyllum japonicum) at UMass, beautifully executed by the pros at Foti Landscape and Tree. Matt Foti just sent me a photo he took last week of the tree, which has settled into its new home nicely.

Though the crew kept a large slug of soil under the tree’s butt for the move, Matt told me that they did some excavation at the root flare, as they always do, to check for girdling, circling, or damaged roots. (I hadn’t noticed the excavation when I first saw the transplant photos, but if you click back to that post you’ll notice it.) The crew found a girdling root and removed it — and clearly, from this current photo, the tree didn’t skip a beat.

Even in a backlit shot on a very hot day this tree is looking happy.

Even in a backlit shot on a very hot day this tree is looking happy.

Read Full Post »

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.

Image

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.

 

Read Full Post »

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.

Image

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.

Image

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.

Image

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.

Image

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.

Read Full Post »

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:

Image

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

Image

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.

Read Full Post »

Last spring I posted photos of a lovely little weeping hornbeam that the Foti crew had transplanted bare-root in downtown Boston a month earlier.  Matt Foti just sent me a couple of update photos, taken when his guys had been down on the Rose Kennedy Greenway to move a collection of trees from one of the park parcels near Quincy Market (a couple of photos from that project will show up in my next post).

The hornbeam thrived through the season, and is doing beautifully.  It had fully leafed out after planting, and the foliage looked awfully good.  Take a look:

Image

Nice dense foliage on the transplanted hornbeam.

Image

This tree apparently didn’t miss a beat when it was moved.

Read Full Post »

…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.

Read Full Post »

This past week I had occasion to pass the same suburban Massachusetts middle school on two days in a row, and on each of those days my eyes goggled at the sight of a new planting on a slope facing the road.  The array of brown, grey, and coppery-red foliage — on the trees that still had foliage — was stunning.  From what I can tell, over the last month or so more than thirty new oaks, zelkovas, and pears were planted as an understory to a mature oak forest.  Did I say stunning?  Yes — but not in a good way.  Most of the trees are dead, and it’s likely that within a few weeks the few still hanging on will die.

You have to admire the forward thinking that gets a new stand of trees started while an existing stand remains; it’s a principle used more in European landscapes than American ones, and we could stand to practice it more here.  It really makes sense to extend one’s planning horizon beyond the span of one’s own life and think both in terms of tree longevity and of the needs of generations to come after us.  The idea of getting young trees established under a mature stand seems particularly apt at on a school property, where adults are fostering the growth and education of children, and tending the young beings who will one day assume adulthood.

So the failure of this planting, installed with apparently the most admirable of motives, seemed especially poignant and distressing.  The tree species selection seemed fine, but it looked as if almost every other element of a planting — root ball size, soil quality, well construction, mulch used (or lack of it), and watering — was inadequate to fulfill the aim of establishing a planting that would live and thrive.

It was impossible to miss this planting from the road below. Virtually every newly planted tree is either dead or nearly so.

From the school drive above the slope, the view is as disappointing. The pears look like the toughest of the new trees out there. Fall color in July is never a good sign, but at least they still have leaves. The zelkovas are mostly bare.

That pile of soil in the foreground is the native soil on this New England upland slope, thin and sandy, with little organic material evident. It appears that the new trees were planted directly into this soil without amendment -- which is fine, as long as the planting crew worked on the root balls to make a rougher interface between root ball soil and native soil. Because water will only move from soil of one porosity to another when the soil is saturated, and roots follow water, you want to scuff up the walls of a root ball to make a less distinct interface between the two soils, and to encourage water and roots to cross the interface.

Tiny root ball? Perhaps. For a 3" caliper tree like this , ANSI standards call for a 32" diameter root ball. The well on this root ball is about 18" in diameter, so it looks as if the root ball is small -- but it may simply be that the well itself is inadequate. Wells should be built outside the root ball wall, so that water is held over the root ball and over the interface between surrounding soil and root ball soil, and so promotes root growth beyond the root ball. Not to mention that these trees were placed right at the drive edge, where their root cannot spread out under the asphalt, and the weight and pressure of plowed snow can tip them...

Another tiny root ball, with a mini-well. The well is very loosely constructed; water has broken through and run down the sandy slope, leaving the tree high and dry. This photo makes me thirsty.

All of the trees are planted on sloping ground, but hardly look it -- another indication that root balls and water wells are too small. Got mulch, anyone? Particularly in this type of sandy soil, a watering schedule and at least a temporary irrigation system (set up to last and run through the first growing season) would help establish the trees. Planting like this has consigned what were once good trees to the chipper.

Egh. More of the same.

What good can be said of this planting?  Well, again, the idea of starting a new generation of trees in an established stand is an admirable one.  The tree’s root flares appeared to be in the proper relation to the surface of their root balls.  Otherwise, it seems to me that this planting is a cautionary tale:  against contractors who do not know how to plant properly, against too-small root balls, poor soils, substandard planting practices, bad tree wells, the absence of mulch, inadequate provision for watering, and inadequate watering itself.  The information on how to plant and foster trees is readily available, so the question may be how do we broaden people’s awareness of it, and their awareness that trees are living organisms rather than tall pieces of furniture?  Any ideas?

Read Full Post »

Older Posts »