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Archive for the ‘Miscellaneous’ Category

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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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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This past summer my good friend, Consulting Arborist Carl Cathcart took me to see an unusual weeping hemlock in a suburb of Boston.  He had shown it to me earlier in the spring, when we got to see it from the road.  This time, he had gotten permission from the owners to examine the tree close up, and so we were very fortunate to be able to stand under and next to it, measuring its stems, its height and width, and generally marveling at its astonishing beauty and size.

The tree’s crown measures approximately 33 -36’ high at its highest point, and approximately 63’ across at its widest spread.  Carl noted that it is averaging 5 1/2 – 6″ of new needled growth all around.

Seven main stems grow from the base.  Their sprawling nature made it impossible to get a diameter at breast height,  but we were able to determine that at roughly 4 ½’ from the ground the stems ranged from 15″ in diameter to 31″ in diameter.  At the tree’s base, we measured a girth of approximately 84″  — this was a tricky measurement to get as some stems grew close to horizontally from the base.  We stood in awe at this magnificent specimen.

Take a look at these photos.  We visited on a cloudy-bright day, the type of day typically good for photographing, but found so much contrast between shadow under the crown and light outside the crown that I resorted to black and white for some photos, the better to show the tree’s form.

It’s not often that we get to see such enormous and grand specimens in this part of the world.  Carl and I appreciated the privilege we had been granted, and hope you enjoy seeing what we saw.

The hemlock from one angle. It sits on a large lawn where it has been allowed to grow in full sun and without competition from other trees.

A slightly different angle. Note Carl's legs under the canopy, just to the right of center.

Carl under the canopy. Note the size of the stems compared the the size of his torso.

Under the canopy.

Underneath, from a different angle.

Not much greenery inside the tree, but plenty outside to make this limb-framed cave.

Magnificent.

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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?

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The other day I was on Beacon Hill and spotted this mostly dead hemlock tree, completely swathed in Boston ivy:

Boston ivy uses this dead hemlock tree as a climbing structure; its owners choose to let the tree stand and continue as a feature in their courtyard garden. Mature trees are rare in tiny Beacon Hill gardens; 'repurposing' this one turns it from an eyesore into an asset.

Perhaps the owners were simply neglecting their courtyard garden, but I like to think that they saw the mature tree’s size as an asset to the place, and decided to use the deadwood as an armature for another plant, and to use the resulting ‘hybrid’ as a garden element.

I have seen this strategy used with other trees; an ancient, mostly dead apple through which a vigorous rose climbs and blooms, tiny dead crabapple that hosts a clematis vine, and a couple of thriving Norway maples whose through whose canopies wind equally thriving wisteria vines.

We see bittersweet and poison ivy taking advantage of the height and sun exposure offered by trees; why not use that principle and foster the growth of ornamental vines over dead trees, or, as in the case of the Norway maples and wisteria, let one aggressive species provide a platform for another aggressive species?

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I took a great class this past January at the Arnold Arboretum.  It was called Grafting Techniques for Ornamental Trees, and was taught by Jack Alexander, the Arboretum’s Plant Propagator.  Jack, who is not only an extremely talented plantsman but an excellent teacher, taught us how to prepare cuttings, how to make several different kinds of grafting cuts, how to fit scion and root stock together, wrap the graft point with an elastic band, and then wrap the whole shebang with Parafilm.

Anyway, at one point during the daylong class  Jack had us take a break from grafting and showed the class some slides.  Among them were shots of a grafting project that he had been commissioned, privately, to work on some years ago.

The tree, located on a property outside of Boston, was a 40-50′ high grafted weeping beech.  It had been top-grafted at a point about 5′ from grade; the trunk below the graft point was about 30″ in diameter, while the trunk above it was considerably larger.

Hartney Greymont, Inc., arborists in charge of the tree, had noticed flagging in the tree’s canopy in 1984.  They hypothesized that the roots could not get enough water up through the constriction to the tree’s crown, and that photosynthate was accumulating above the graft point.  They called in Jack Alexander to do some grafting that could help improve the situation.

The problem:  Constriction at the graft point was retarding the flow of water up to the tree’s canopy, and possibly preventing photosynthate from flowing down to the roots from the crown.

The solution:  Remedial grafting, using four beech saplings to create supplemental trunks.

The process:  In the fall of 1984, Hartney Greymont planted four 2-3″ caliper (3/4″ dbh) beech saplings around the tree, evenly spaced from each other and about 3′ out from the tree’s trunk.  The saplings settled in over the winter.   Jack, who had the experience and expertise to work comfortably with such a valuable tree, then grafted the tops of each sapling to the trunk of the specimen beech above the graft point. This process is called inarching.  Jack believes he performed the grafts in April of 1985.

The newly inarched beech, with three of the four saplings planted and grafted above the beech's graft point visible here. Matching the cambium of the saplings to the cambium of the mature tree allows photosynthate from the tree's crown to flow down the sapling trunks, supplying them with nutrients that otherwise would serve to overenlarge the beech's trunk just above the graft point, making the tree more susceptible to failure. The inarched saplings make a conduit for water to flow upwards into the canopy from the roots as they benefit from the abundance of photosynthate, and in turn enhance the tree's stability. Photo Copyright © 1985 Jack Alexander, used by permission.

The following year, one sapling had died, so Hartney planted another, and Jack grafted it to the tree in the spring of 1986.  A total of four buttress trees now help support the specimen tree.

The result:  Photosynthate flows down from the tree’s crown through the constricted graft point, as it always has, but it also flows down through the four inarched saplings.  Because the saplings are being nourished by the mature crown of the specimen, over the last 26 years they have come to serve as living buttresses to the mother tree.

In Jack’s words:  “By grafting additional rootstocks, we provided roots to provide more water to the top where it was flagging. The additional roots systems grew rapidly, tending to corroborate the opinion that there was a surplus of photosynthate accumulating above the graft union.”

A few weeks ago, in late April 2011, Carl Cathcart took me to see the beech.  The house had been sold since the beech had been buttressed, but the current homeowner was kind enough to let us see and photograph it.  Here are photos of it as it stands today.  It was wonderful to see this behemoth and to read its character, especially knowing its history.

Carl Cathcart with the inarched specimen weeping beech.

The beech from a different angle. What look like elephant legs under the tree are the ingrafted saplings that have now become living buttresses.

Three buttresses are visible in this image; the smallest is about 6" dbh. This photo was taken from about the same point as Jack Alexander's 1985 photo.

When I sent the photos to Jack, he wrote ” It’s nice to see these pics.  The tree seems like an old friend.” You can see why — this is a tree with personality, and Jack did some remarkable work with it.

Propagator/Grafter:  Jack Alexander

Arborist in charge:  Hartney Greymont, Inc. 

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If we can clone crabapples, maples, and chamaecyparis, why can’t we clone the enormous redwoods that stand as the world’s tallest trees?  Well, apparently we can. This article in Sunday’s New York Times (4/10/2011) explains how a group of arborists dedicated to propagating and planting clonal stands of coastal and giant sequoias, using tissue and cuttings harvested from the sprouting stumps of sequoias that have been cut down.   It’s a compelling read, has good pix, and might leave you with something to chew on.

 

 

 

 

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