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Posts Tagged ‘Plant management’

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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Yesterday I swung by the site where Herbie, the American Elm in Yarmouth, Maine, had stood for over two centuries.  Herbie was taken down last January; to read the tale see this post, and to see photos of Herbie’s stump, click on this link.

I hadn’t planned to stop and see the stump — what more could be said about a stump?  As the exit from Rte. 95 neared, though, I wondered if anyone might have put up any signs, or even if some of the woodwork from Herbie’s wood might be displayed on the site.

It wasn’t though, and in fact all that remained of the stump was an area, approximately 12′ x 18′,  of wood chips.  Herbie’s stump had been ground.  The adjacent road has been undergoing repaving, and stakes and markers dot the roadside and the edge of the chipped area.  We’ll have to wait and see what takes place now where Herbie once stood.

All that remains are wood chips, an open space, and a view of the utility pole.

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Last year I worked on a large mall planting project.  A number of trees had to be pulled out to make way for a new parking layout; the islands they had been growing in were removed and paved over, with new islands located in a different configuration.  Most of the trees were hauled away by the landscape contractor, but one ended up in a discard pile next to the mountain of loam that had been excavated for reuse.

I was interested in the root configuration on this six-inch caliper red maple.  A mass of fibrous roots wrapped closely around the tree’s trunk, much like cotton-candy filaments spun around a paper cone.  Looking at it more closely, I found that the fibrous roots grew out of thicker woody roots, some of which had been cut during the tree’s original ball-and-burlapping, and some of which, growing since that operation, were circling the trunk.  Take a look:

Fibrous roots circling the six-inch red maple trunk.

Pulled away from the trunk, the roots clearly are circling it. Over time, as the tree grew in girth, these roots likely would have constricted the flow of nutrients between root mass and crown

This sort of circling root is usually seen when the soil mass in a B&B root ball is of different porosity from the soil surrounding it; moisture will not move from one soil mass to the other until one mass is completely saturated.  Because roots tend to grow where moisture and oxygen are available, they will often stay within the root ball, and circle around the trunk as they grow.  The problem is made worse when burlap is not pulled away from the ball, as the burlap constitutes yet another interface for the moisture to move through.

Here's the tree's underside. Note the girdling root snaking on top of the big torn root facing the camera, and the curiously self-contained look of this root mass. The tree's problems likely began early in its life.

Not every B&B tree has these problems, and in those that do, not every rooting problem can be remedied at planting time.  Judicious treatment — looking for circling roots that can become girdling roots, cutting back girdling roots and cutting or redirecting circling roots, roughing up the sides of the root ball, removing or cutting down wire baskets, pulling down or removing burlap — can go a long way in helping B&B trees establish better in the landscape, and in remedying problems that threaten a tree’s long-term health and viability.  For more discussion on root issues affecting B&B trees, check out this post on Matt Foti’s station at the MAA’s Elm Bank bare-root workshop in September 2009.

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Last week I drove to Wellesley College to see the Dwarf Alberta Spruce that Jim Doyle and Don Garrick had moved bare-root last November.  Fritz Hoffman, an Alaska contractor in town to learn about bare-root transplant work, accompanied me, and we walked and walked along the lakeshore looking for the Spruce.

Well, it wasn’t there.  We turned around, backtracked along the pathway, and came upon a grounds crew working on a plaza installation.  We stopped and met John Olmsted, Manager of Landscape Operations, who told us that the Spruce had died.  He said that despite its loss, the arborists had recently transplanted a Sugar Maple, two Kousa Dogwoods, and an American Smokebush bare-root.

The Dwarf Alberta Spruce didn't make it, but this spring-transplanted Kousa Dogwood may well thrive in this spot.

Later, Jim Doyle told me that he thought they had moved the Spruce to a too-exposed location.  It seemed to fare well through the winter, but in March had turned brown and had to be removed.  We speculated that the move from a very sheltered spot to an open waterfront location might have placed too high a demand on the plant.  It might have survived the dangerous phenomenon of frozen soils and warm air had it been wrapped in burlap, but it’s impossible to know.

Nice trunk flare on the newly transplanted Sugar Maple at Wellesley College.

What is heartening is that the Spruce move came about because Jim and Don took a chance — and though the risk didn’t pan out, the College believed in the possibility of success, and authorized the bare-root moving of four more plants.  When it comes down to a choice, especially on a large campus, between moving or destroying a tree, the opportunity to move and save the tree may make sense.   Actively managing a landscape — especially one with valuable mature trees —  requires this kind of decision-making, and newly available technologies can give greater flexibility in the move-save debate.

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Yesterday I drove through Yarmouth, Maine, and stopped by the site where Herbie the New England Champion American Elm (Ulmus americana) had lived for over two hundred years before meeting his end this past January (see this post for the story).  I wanted to see Herbie’s stump and get a better idea of what 217 years of tree age looked like in plan view.

It was hard to get a clear measure of the stump.  It was cleanly cut across the root flare, and there were no signs of internal decay at the cut line, which indicates that no root damage — or none of the kind that travels up the trunk and compromises it —  had affected the tree in its life.

This tree was big.  A slice from the bottom of the butt, mounted on table-height legs, would be big enough to seat at least a dozen people quite comfortably, if a bit irregularly.  The following photos show my attempts at comparative scale.

From a distance, the spot where Herbie stood looks like a small paved dais in a big open space.

A pair of Felcos and a water bottle for scale, and still it's hard to fathom the stump's size.

Hmm. This yellow nursery caliper gauge, maxed out at 4 1/4", doesn't come close to an appropriate scale. The school bus in the background ran past before I could catch its image right in front of the stump, but it begins to suggest a comparison.

This angle doesn't help much either, though it certainly illustrates how Herbie dealt with grade change -- he just grew over it.

People walking by help with scale.

Eureka! The handy measuring tape, laid across the stump's widest part, gives at least some numeric sense of size.

Here's a crop from that last photo, showing the stump measuring at its widest point 9'-2". Herbie had plenty of root room, among other advantages, so he could grow to this size.

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At New England Grows, I met Jim Doyle, one of Wellesley College‘s team of arborists. He told me about an air-tool transplant that he and a colleague performed last November at the College.  He was kind enough to send photos, and with them included this text, which I have edited only slightly:

“My colleague Don Garrick and I performed the transplant on Nov. 3rd 2009.  The reason for the transplant was that the tree, a Picea glauca ‘Conica’ (Dwarf Alberta Spruce), had outgrown its current location and was providing too much shade to the greenhouse.  An old accession tag we found told us that the tree had been planted in 1956.

The tree in its original location, quite close to the greenhouse.

Jim using the airspade to locate the root zone's outer limits.

Don digging a trench outside of the root zone.

In this and in the next two pictures, Jim removes soil from the Picea's roots.

  

Working in from the perimeter toward the trunk.

Don lifts the tree out of the hole.

Transporting the tree to its new home across campus. The tree has been laid down for stability.

The tree in its new location, with plenty of room for continued growth up and out.

During the whole process we watered the roots every 5 to 10 min.  We wrapped the roots in wet burlap for the transport.  Once we had placed it in its new home, I sprayed the tree with with anti-transpirant and we then staked it, as its new home was a very windy location on the lake.  The stakes and guys will probably be removed this summer once we can confirm that the tree has settled well enough in its new hole.”

Here’s an example of the thoughtful management of plants on a property.  This Dwarf Alberta Spruce was in good shape, but had grown out of its original location, tucked behind the greenhouse.  Moving it was a fine way to save the tree, preserve the antique greenhouse glass adjacent to it, eliminate the greenhouse interior shading problem, and revamp the area — and now the tree, in its new spot, has room to grow and is visible to the Wellesley College community.

Project site:  Wellesley College campus, Wellesley, MA

Project arborists:  Jim Doyle, ISA-Certified Arborist; Don Garrick, MA-Certified Arborist

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Thousands of people showed up at New England Grows this past week.  One of the conference’s principal speakers, Bonnie Lee Appleton, unfortunately fell ill and had to cancel her Wednesday talk; for a while the day before the conference it looked as if one of the two convention center ballrooms would be empty for a couple of hours.  At the last minute, NE Grows asked Matt Foti to take Ms. Appleton’s place with a talk on bare-root planting.

The talk was great — packed with information — and sent a steady stream of people to the Foti Tree and Landscaping booth to learn more about bare-root transplanting.  Matt teamed with Teddy and Mike, two of his arborists, to field questions at the booth, which had a good set of air-tool transplant photos, a continually running rough cut of my London Plane video, and two 3-inch caliper Zelkovas from Matt’s nursery. One of the Zelkovas had been dug, balled, and burlapped; the other sat with its bare roots splayed on a sheet of plastic, showing off their extension (they extended about 3-4′ on all sides from the tree trunk), uncut tapers, and web of water-collecting and nutrient-storing capacity.  Every now and again one of the arborists would spray the roots with water.

It was cool to watch visitors to the booth stop and take in what they were seeing.  Some of them shook their heads and moved on; most, though, would watch the video for a few moments, or peer at the photos and the trees and start asking questions.  Matt and Timmy and Mike rarely had a moment in the three days when they weren’t answering questions.

A couple of questions popped up over and over.   Arborists, landscape architects, designers, and contractors all wanted to know how much air-tool transplantation costs.  The answer, based on labor requirements, species, condition, and size of tree, as well as on site conditions, was that bare-rooting a tree for transplant may cost more than digging it with a tree spade, but less than digging it with the more traditional drumlaced B&B method.  Bare-rooting a tree for transplant typically preserves at least 90% of the tree’s roots, though, a claim that cannot be made for the other methods.  The more roots you save, the less transplant stress and the shorter the tree’s reestablishment period — and all other factors being equal, the healthier the tree tends to be after transplant.

The other question, also coming from arborists, landscape architects, designers, and contractors, was about taproots.  How did bare-root transplant affect a taprooted tree?  The answer is that taproots are rarely an issue, at least in this part of the world.  In New England, soils tend to be shallow.  As we know, 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 do extend vertically down in this zone, but many more run horizontally away from the tree’s trunk.

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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I was in Maine last week, and planned to stop in Yarmouth on Monday to watch the removal of Herbie, the champion American Elm (Ulmus americana) that had finally become too compromised to stay standing.

For several months,  stories about Herbie and his long-time steward, Yarmouth tree warden Frank Knight (at 101 years old, he is now retired) had been appearing in the news — Knight had cared for Herbie for over 50 years, and had treated the elm in repeated battles with Dutch Elm Disease.  He had succeeded for decades, but in recent years the disease and old age had been catching up, infecting whole limbs and making it necessary to remove large chunks of the tree’s crown.  Last summer, the town’s current tree warden, Debra Hopkins, determined that Herbie should come down, and Knight concurred.   The date of removal was set for January 18.

There were reports that arborists and Herbie-fans from around New England would show up to watch the proceedings.  As I would be driving past Yarmouth that day, I decided to join them.  Work was slated to begin at 7:30 a.m.

Fortunately or not, a heavy snowstorm started on Sunday night, and when I awoke at 5 on Monday morning several inches had already fallen, with no end in sight.   A couple of tasks delayed my departure by several hours, and as it seemed unlikely that the work would proceed that day anyway, I didn’t arrive in Yarmouth until about 2:30 p.m.  Herbie still stood.  As I drove up, several people were snapping photos of the tree; more showed up when they left, and still more arrived as I was leaving.  Lots of people wanted to get a last look at this giant.

Herbie the American Elm, on the day scheduled for his removal.

Herbie was massive — in his prime, he stood 110′ tall, with a crown spread of 120′ and a girth of 20′.  Disease and age had diminished him, and it was clear that this was a tree under serious stress, but it was impossible to stand next to or near him without feeling awe.

To get a sense of the tree's scale, note the people standing to the left of Herbie.

Someone had tied a red, white, and blue ribbon around the tree, and people had attached cards and well wishes and information on this champion to it.

The placard in the middle is an 8.5" x 11" sheet of paper, with facts on Herbie's size and life.

The tree had quite a lot of evidently viable growth in the canopy, but the canopy itself had been hugely compromised, with several very large limbs removed.  I remember hearing Alex Shigo talk about how and when to make the decision to remove a tree; he spoke eloquently about the native dignity of trees, and about how at some point the act of removal shows more respect for the tree than leaving it in place.

There comes a point in a tree's life where removal of this much of its crown is a removal of dignity, as well. Though the tree's trunk appeared to be sound, and the limb removals had eliminated hazard wood, Herbie's time had come.

For about 15 minutes, I ran around in the cold photographing Herbie from different angles.  As I did, I saw carloads of people arrive, jump out, snap photos of themselves with the tree, put a hand out to feel its bark, and then gaze up at it reverently before they left.  And then I went over, put my hand on the craggy, lichen-speckled bark, and also said a silent goodbye.

Herbie in his heyday. This was a classic American elm.

Herbie was taken down the following day, with Frank Knight in attendance.  To see removal photos and videos, as well as how the wood from this elm will be used, click on this link.

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I just got a rough cut today of the video, shot last summer, of the moving of a very large (about 14″ caliper, 30′ height) London Plane Tree.  It’s taken a while to edit several hours of footage down to a half an hour, but it’s about done, and in the next few weeks I hope to have added commentary.  This video is from the project run by Matt Foti’s crew, aided by Mike Furgal, and it showcases the techniques used in air-tool transplanting.  I hope to be able to preview the rough cut at New England Grows, and have the final version completed by the end of February; if there’s enough interest in the arborist community I’ll sell copies.  Stay tuned.

The first of five 12-14' caliper London Plane trees being excavated with air tools and transplanted bare root in August 2009.

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