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Lightning Strike

Categories: Trees, Weather

Our wild and crazy summer weather here at Middlebury continues, this time with a tree being struck by lightning. (Side note to the faithful readers out there. I feel for you-has this blog been getting depressing lately? With vandalism, more vandalismstorms, more storms, even still more storms, and disease,  it seems like the Middlebury Landscape is getting tragic. Hold the faith! We’ve been planting as well. Posts coming soon on this year’s tree plantings, as well as a new look for Pearson Hall.)

Ginkgo at 121 South Main

The tree hit is a Ginkgo ( read here if you’ve forgotten about them) located in front of one of Middlebury’s “outside” houses, near Public Safety at 121 South Main Street. I don’t know the night it got hit, but it was brought to my attention by one of the diligent members of our crew. Looking at the tree originally, I first thought the tree had just cracked down near the base, possibly in some strong wind. The tree shows what arborists call co-dominant trunks, where two trunks of equal size meet and grow together. This is frequently a recipe for disaster, as a bad union often results, where included bark makes a weak joint, and the two trunks typically fall apart away from each other.

Co-Dominant Trunks-click for a larger view to see the wound

I called an Arborist friend to consult on the damage-this is one of our favorite trees in Facilities, many of us would mourn the loss. His skill, knowledge, and experience led him to look up the tree, rather than me just jumping to the first obvious conclusion, and that was how he discovered the damage around the cable up top, as well as noticing the toothpick sized wood pieces scattered around the yard, small pieces of trunk blown away from the tree from the force of the lightning. Being tree geeks, we climbed up to investigate.

Damage around one the cables

Damage on another limb-the lightning jumped to this branch

Trees are frequent targets of lightning. Standing alone, frequently taller than many buildings around them, many trees get hit each year. Lightning is fascinating all on it’s own, with their impressive 100 million volts and  temperatures greater than 50,000 degrees fahrenheit. 16 million lightning storms are estimated worldwide in a year, and measuring instruments record over 100 million strikes in the U.S. each year, killing on average 90 people. They even get their own phobia, Astraphobia, fear of lightning.

The conditions needed for lightning are still debatable, but should those conditions exist, negative ions accumulate at the base of the storm clouds, while positive ions pile up on the ground. “Stepped Ladders” descend from the clouds, while “streamers” arise from the earth, typically strongest from the tallest structures, such as buildings or trees. Should they build strong and fast enough, they meet to form a lightning bolt, and this electrical discharge super heats the air around it to 36,000 degrees fahrenheit, compressing the air creating supersonic shock wave we hear as thunder.

When lightning strikes a tree, the sap in the tree boils, turning to steam and blasting the bark away from the trunk. The electrical charge flows through the tree, exiting out the root system, which could be severely damaged in the process, sometimes with no visible sign above. In most cases, though, a strip of bark is torn from the tree, often in a long strip, but sometimes, like this ginkgo, only above and below. Trees with only one crack tend to close the wound and suffer, yet live, while trees with wounds on both sides of the trunk are frequently killed outright. Obviously, even a wounded tree can die from secondary reasons, such as insects and diseases, less able to fight them off.

Trees vary in their susceptibility to lightning strikes, possibly for biological reasons, or possibly simply because of their height. Elms, Oaks, Black Locust and Ash tend to be very susceptible, while Beech, Horsechestnut, and Birch tend to not be very susceptible. It may be the starch content of the tree making it more susceptible, while resinous trees are poorer conductors.

So there is hope for our Ginkgo. The wound at the bottom was traced, where loose bark is peeled away carefully from the trunk to the point where it attaches again. The thinking with bark tracing is that loose bark can trap moisture and disease, so by removing it the wound can dry better. Maybe it’s just something to do to make arborists feel not quite so helpless…

Lower wound after tracing

Lower part of wound where lightning went to ground

The cabling up in the crown of the tree is a little more problematic. Originally put in place to help stabilize the two co-dominant stems, the system now obviously cannot be trusted, as the wood surrounding the bolts holding the cable is now dead. We decided to replace the cable with two others, one above the old cable (a better location from an engineering perspective), but also one looser below, in case one of the stems fails completely at the original cable site, and breaks. The tree will then still be braced by the lower cable.

Placing the cables in the tree

The three cables in place

So now, we wait. The rest of this year, and into next spring, will be the crucial time, and when we shall see just how bad the strike was. Should it still appear somewhat healthy next spring, we will aerate the soil around the tree, add compost, fertilize, and mulch. Hard to imagine now, but, if we get a little drought this summer, we’ll even go down to water.

When Good Plants go Bad

Categories: Insects and Diseases

My most depressing year at the University of Vermont would have been my junior year. All plant and soil science majors took Plant Pathology that year, two semesters worth. For all of you non-science plant geeks, plant pathology deals with diseases of plants-basically anything except insects. Virus, fungi, bacteria, even abiotic problems were addressed. After a year of learing the various ways plants die, I remember thinking about the hopelessness of it all, wondering how on earth plants even existed.

Insect pest management was the previous year. Insects, while a pain, can very often be sprayed, attacked by other bugs, or even crop rotated away. But most of plant pathology? Hopeless. At best, they are “controlled”, like most fungicides, at worst, well, here’s a list of plants if you have to replant that may not get that disease. No magical sprays, potions, or elixirs to help you along. Often the best defense against many of these problems is simply a good offense-a healthy thriving plant will suffer some little indignities here and there, but will fight on.

The recent spate of warm and wet weather has Verticillium Wilt  rearing its nasty little head around. I’ve gotten several emails about it recently, and am expecting more. Verticillium Wilt is a soil borne fungus that enters the roots, then both produces toxins and spreads spores throughout the xylem (water tissues) of the plant. The plant, in a bit of idiotic self defense, uses various compounds to plug the xylem further, ostensibly to stop the spread of the  fungus, but further restricting water movement inside. The name wilt is a descriptive, as the first symptom typically seen is the last, as the leaves wilt and die from lack of water.

In fruit trees, the fungus is called Black Heart, commonly seen in Apricots, but is also seen in many types of plants, such as potatoes, tomatoes, mint, and many types of trees and shrubs. The fungi, Verticillium albo-atrum or V. dahliae, can persist in the soil for up to 15 years, forming small black resting structures activated when roots grow near them.

On campus, Verticillium wilt is evident on some older plantings of lilacs, like on the picture below. This particular clump is near Battell, on the wetter, or beach, side. Lilacs don’t like wet feet (roots) to begin with, and this may help bring about the fungus.

Lilacs at Battell


Verticillium symptoms on Lilac

Another victim of Verticillium seems to be a Catalpa, know by my kids as the Green Bean tree, for the size seed pods it produces. Spectacular in flower, this tree was the subject of my first Twitter picture about a month ago. (Are you following Middland on Twitter? I’m having a blast posting pictures of plants in bloom around campus, I’m at http://twitter.com/middland.)

Verticillium wilt in Catalpa

The location is directly across from Emma Willard, blocking one of the special sightlines at Middlebury, that of the view from the front of Emma Willard looking up towards Old Chapel. While I mourn the loss of all trees, more than one person has lamented the unfortunate planting location of this tree, wishing it were elsewhere. This loss is particularly wrenching for me, as I watched it come down with this disease last year, but then watched it leaf and flower out again this spring. Thinking Verticillium more quickly virulent, I had false hope this spring, and now know better. Fortunately, the next nearest tree is a birch, resistant to Verticillium, so this loss should be confined to a single tree.

Wilting leaves on Catalpa

Another Day, another storm

Categories: Trees, Weather

The storms certainly keep coming, and, worryingly, the trees keep succumbing.  Today at 3:30 a very brief but intense cell blasted through campus. We’d lost power for a little bit, I don’t know why. The weather station recorded about 1/4″ of rain in 15 minutes, with a peak wind gust of 35 mph, from the north. This was enough to take the life of a poor Hackberry tree.

Hackberry by Warner Science

This poor tree had been scarred at the base years ago, maybe by a random mouse, maybe by something mechanical. At any rate, the worst place to wound a tree is right at the base. A tree has a very hard time compartmentalizing the wound at the base, and structural integrity of both trunk and root system is compromised. Look at the picture below-the wound was on the north side of the tree. The roots rotted away on that side, and the strong north wind gust toppled the tree right over.

Base of Hackberry

I took these pictures on my way home at 4, but I would imagine the rest of the campus trees are fine. A perfect wind knocked this one down. I’ve already got a replacement in mind.

EDIT: Middblog just posted some YouTube video of the rain here-it’s impressive.

If a Tree Falls…

Categories: Trees, Weather

I’m not much of a Twitterer, although I’ve been called a twit many times.I don’t want to get tweets on my cell-my phone vibrates so violently at the slightest ring or text message that while weeding I end up shrieking like my 10 year old thinking I just weeded a bee’s nest. But I do check some from time to time, MiddBlog being one of my favorites, and they cross-tweeted (is that the right phrase?) a posting from Audrey Tolbert, who with Cody Gohl are blogging their Middlebury summer. (They are going to learn the Vermont secret-we put up with winter for the summer. Not too hot, not too sticky, and, so far this year, not too buggy.)

Anyway, she posted a picture asking“If a tree falls in Midd and there’s no one on campus to hear it, does it make a sound?”. Yes, Virginia, it certainly does.

Silver maple-Hillcrest Road

Silver Maple-Hillcrest Road

This is a Silver Maple tree behind the Chellis House. The storm I reported on last week, well, this was one of the trees that fell over. The picture does not do the size justice, as the trunk of the tree was at least 4′ in diameter. Look carefully, you’ll see about 1-2″ of live wood around the trunk, and the rest was hollow.

Close Up of trunk

One of the surprising things about this tree falling was its aim-it fell in absolutely the perfect direction, missing the woodline separating Hillcrest Road from Adirondack Road, missing Chellis House, the Queer Studies house, and the garage next to Chellis. We couldn’t have asked for anything more.

I wasn’t going to write about this poor tree. I am actually embarrassed by this. While I knew the tree had structural problems, I had no idea the extent of the damage inside the trunk. Look at the close up picture-those are weeds growing between the main stems at the top of the trunk. Large trees like this will often collect leaves there, and eventually grow things. It is the trunk decay that is surprising, and I feel like I should have known about this problem. Two arborists I respect both looked at this tree, though, and said that I had no way of knowing how bad it was, that they see this all the time, one going so far as to say “this is what Silver maples do.” So they made me feel a little better, and now I’m not blushing in embarrassment posting these pictures.

This tree is now cleaned up and gone. We’ve caught up on most of our storm damage, thanks to some very hard work by our landscape department and some excellent outside contractors. The elm I wrote about below Mead Chapel is OK, although more bare now. Once the hanging branches were pruned out there was more left of the tree than I had first thought, so that’s good. Many of the elms had some broken branches here and there, and a handful of other trees on campus had a branch or two break. Overall, not as bad as it could have been.

Black Locust

Categories: Trees

There is an area of campus called Stewart Woods-it’s south of Stewart Hall, on the other side of the road, next to the graveyard. Our department mows underneath the trees, forming a beautiful little grove next to the road. The trees are black locust, Robinia pseudoacacia, and are in full bloom right now. A favorite of honeybees, walking over there you can just hear the air humming with the sound.

Stewart Woods in bloom

Stewart Woods in bloom

Native from Pennsylvania to Georgia, west to about Oklahoma, early settlers have since dispersed the tree far and wide. Like the lilac, old house and farm sites in Vermont can often be found by the black locust trees nearby. They had multiple uses back then, and still would, were it not for the locust borer, a destructive insect wiping out nearly all the magnificent trees in the prime of their life. The trees grow in groves, suckering up from their roots, making sharing trees with your neighbors easy. (This is like a lilac as well-popular early colonial plants were easy to propagate.) The wood was used not only for burning, with a very high BTU, matching an equal weight in coal, but also for fence posts, nearly never rotting when in contact with the ground. In fact, Donald Peattie in “A Natural History of North American Trees” quotes mark Catesby, a British naturalist who visited Jamestown a century after it’s founding. He states “they erected each of their little hovels on four only of these trees ( the locust tree of Virginia), pitched into the ground to support the four corners; many of these posts sare yet standing, and not only the parts underground, but likewise those above, perfectly sound”.

So, apparently, no “log cabins” for our early settlers, but an impressive grasp of the semi-colon.

The latin, Robinia,  honors either Jean Robin, or son Vespasien, who grew seeds of the tree sometime between 1601 and 1636, and introduced the tree to France, where it became all the rage. The wood is so strong, it is also used for nails on ships, lasting longer than the hulls they held together. The British used the superiority of our hastily built “locust fleet” as an excuse for their defeat on Lake Champlain in the war of 1812. The nails, also called Trunnels, took advantage of the nature of Locust wood, that when wet it expands and becomes leak proof.

Peattie expands the tree nails story, writing of William Cobbett, a famous English publicist and economist, who between 1917 and 1819 started a Black Locust grove on his farm on Long Island, hoping to supply the British navy with tree nails. He had to hurridly leave what he undoubtedly still called the ‘colonies’, having been chased out by popular opinion for libeling Dr. Rush for having killed George Washington by malpractice. He returned to England with some Black Locust seed, and the corpse and coffin of Thomas Paine, planning to re-intern the body in a spectacular monument to atone for his former attacks on the author. He never finished, the coffin auctioned to a furniture dealer, the corpse inside lost to history.

A special strain of Black Locust used to be described as “Shipmast Locust”, having perfectly straight and clear trunks for many feet, yielding valuable timber. It used to be described as a separate species, until botanists yelled foul, merging it back with the normal Locust, as it was probably just a cultivar asexually propagated by root suckers.

The tree itself grows fairly straight, only branching at the top. The leaves are a nice light green, aboiut 6-12″ long, with many leaflets at about 1-2″. The leaflets fold up at night and droop, making people believe the tree is conserving water, but that is a non-issue at night, so other guesses must be made.

Black Locust Bark

Black Locust Bark

 The bark is a light grey, but unmistakably furrowed and rough. The blooms are white, and hang in clusters 4-8″ long  from the branches. The scent needs to be experienced, but is spectacular.

Black Locust Flowers

Black Locust Flowers

Gardeners would recognize the bloom as similar to peas, and indeed they are in the same family. Black Locust has the ability to fix nitrogen, like all legumes, so the tree is often listed in the saddest of all plant use lists, Mine Reclamation. Micheal Dirr calls it an “Alley Cat Tree”, more as an indication of hardiness and usefulness than anything else. It is a common tree in China, and is called “yanghuai”, or Foreign Scholar Tree, as it does mimic the Scholar Tree native there.

There are many Black Locust trees on campus aside from Stewart Woods. Off the top of my head, I can think of Nichols House, below the ledge at Gifford, McKinley House, and next to Hillcrest Road. The oldest and largest are probably at the McKinley House.

P.S.- A public apology. While running a garden center and growing trees in pots, I became enamoured of a cultivar of Black Locust called “Purple Robe”.  This was a beautiful tree. Nice round shape with good branching, not like a normal locust, crisp lime green leaves, and spectacular purple flowers instead of white. We grew and sold many of them, and it was easy, for they grew fast and looked good in a pot. I even planted one in my back yard, and it would slow traffic down on our road in flower.

Purple Robe Locust Flowers

Purple Robe Locust Flowers

After several years, the trees started falling apart, literally. Some would get a couple of locust borer holes, and snap in half at a gust of wind. Others would branch poorly, and split down the middle. Still more woiuld get riddled with borer holes so bad as to just up and die. Mine did all three.

I only mention all of this because I still run into former customers in town that will not talk to me, or even nod a hello, mad at me for making them fall in love with a fast growing shade tree that died a premature death. It’s terrible to see a tree die in the prime of its life, and believe me, had I known, I wouldn’t have grown or sold them. Sometimes a plant that does well in one part of the country does poorly elsewhere, but that’s not really an excuse, is it?

Teaching with Technology Fair

Categories: Random Thoughts

It’s Commencement (literally, it’s about 9:30 Sunday morning, we’ve been at it since 5 Am, but now us landscapers are hiding around campus working where you can’t see us), hence the lack of any posts the last week or so. I’ve got a lot to write, but being a landscaper in spring has it’s disadvantages, time management being a one of them.  I just wanted to mention I’ll be at the Teaching with Technology Fair on Wednesday, in the Great Hall at Bicentennial Hall from 10-12, showing off the Campus Tree Map. If you’re curious as to the ArcGIS underpinnings of the map, or just want to drop by to talk plants, come on over.

More Vandalism

Categories: Trees

Scene of the crime

Scene of the crime

I read with interest the recent article in the Middlebury Campus on the increase in vandalism this year, as I completely agree. We’ve recently lost another tree to senseless idiocy, this one a rare Silverbell. We’d only planted this tree about a year and a half ago, and it was ripped up out of the ground about 2 weeks before it was due to flower. I could see the little flower buds shriveling up and dying right before my eyes. Not only was this tree ripped up out of the ground, but it was snapped in half at the base as well, I guess in case the first injustice wasn’t enough. This was outside of Allen Hall.

Close up of root system

Close up of root system

That same weekend, someone felt the need to do a little pruning on a paper birch outside of Battell.

The branch as found outside Battell

The branch as found outside Battell The tree

Maybe what concerns me the most is the possibility that, because most of the plant vandalism seems to be taking place outside of freshman dorms, we may be in for 3 more years of this. Once again, any ideas are welcome on how to fix this as a community.

Most Beautiful Parking Lot, Ever.

Categories: Landscape, Trees

Is there a contest out there for most beautiful parking lot? I can’t seem to google one, but if one turns up, I’m nominating the the Mahaney Center for the Arts parking lot-the big one off of Porter Field Road. Monocultures are verboten in the arboricultural world, but this singular planting of ‘Snowdrift’ crabapple transforms a blacktop wasteland with nice views of the Green Mountains to something totally magical for a week or so in the spring.

DSC04348

 

DSC04347

Snowdrift Crabapples have a great shape, with almost no variation in the population, making it predictable, and therefore enjoyed by landscape architects who don’t trust their plantings to trees that may take any old shape they want. The cultivar gets a nice dull gold fall color, and reddish orange fruit that birds wait and eat in the spring (at least in my yard, returning Robins mostly). While the name may have come from the flowers on the tree, I prefer to think it was named for the petals as they fall on the ground, all at once, blowing against the curbs and tires.

DSC04349

Happy Arbor Day!

Categories: Trees

A final reminder to join us, 3:00, on the McCullough Plaza for a tree walk around campus, followed by a tree planting by Bicentennial Hall. Come learn about the trees around us, and make your mark on Middlebury by planting something you’ll watch grow for the rest of your life.
As part of her class project in the Trees and The Urban Forest winter term class, Laura Budd took the tree inventory of the Middlebury College Campus and ran it through iTree, modeling software that quantifies the benefits of a urban tree population. Today seems like an appropriate time to remind everyone of what our campus trees do for our environment.
2.75 million gallons of Stormwater intercepted

270,000 lbs of carbon sequestered yearly, 616,000 lbs sequestered and avoided, and 5.36 million lbs stored in total

3156 lbs of air pollutants captured or avoided, including 807 lbs of ozone, 1580 lbs NO2, 778 lbs SO2, and 503 lbs of PM10.

Arbor Day This Friday

Categories: Trees

Come get your hands dirty, and plant some trees. Arbor Day is coming to Vermont, this Friday the 7th, and we are celebrating. Start with a Tree Tour, led by yours truly, starting at the McCullough Plaza at 3 PM, and end up at Bicentennial Hall about 4:00. Plant some trees with students around Bi-Hall, and enjoy refreshements generously provided by the Mountain Club. Once we’re done, go enjoy the all campus picnic at Battell Beach. (No, we didn’t plan that, but pretty cool nonetheless).

“He that plants trees loves others besides himself.” -Thomas Fuller