Posts by Tim Parsons

 
 
 

The Botany of Syrup

Categories: Midd Blogosphere

Any kid will tell you maple syrup is special, but how special? Is tapping a maple tree like putting a spigot in the trunk? And why maple?

In a wonderful book I’ve written about before by Nalini M. Nadkarni called “Between Earth and Sky-Our Intimate Connection to Trees” she writes of how botanists and tree physiologists have been looking at how sap is produced within maple in the last couple of decades. Like many things, the wild world of maple syrup seems like a freak chance, a perfect random combination of physiology.

A tree’s goal, aside from reproduction, is to feed itself-it’s tough being an autotroph, and a whole lot of work. Photosynthesis takes place all summer long, making sugars for respiration, growth, reproduction, and a little extra. This extra, in a sugar maple, gets stored as starches within the sapwood of the tree. The sapwood, as the name sounds, is the area of the trunk and branches where water and sugars move around, located within the first couple rings of the wood.

As my winter term class hopefully remembers, Sugar maple is one of our “live slow, die old” species of trees. These trees are more shade tolerant, in life for the long haul, and have the foresight to save extra sugar for lean times, such as the introduction of shade or competition. Other tree species, such as Poplar, live fast and die young, and burn through all their sugar like a hyper 3 old, just as prone to growth spurts as an Aspen in the spring.

Early spring brings sun, a little higher in the sky, and better able to warm. Cats in our house know this, moving away from the woodstove and into little patches of sunlight on soft surfaces. Trees know this too, as the sun warms the bark and the wood. The air may be below freezing, but tree surfaces and interiors could be well above freezing. Once the wood gets to be above 40 degrees, enzymes turn these stored starches into sugars, mostly sucrose, and the sugar is now within the sap. This explains the magical sugaring temperature of 40, any warmer and this process stops.

The other freak chance miracle of maple is getting the sap flowing out of the tree. Not all trees can do this. Water is moved throughout the xylem of the tree by capillary action and transpiration, meaning the leaves need to be on the tree for water to move very effectively. That  would ordinarily make for tough sugaring in March and April, except in Maple.

In maple trees the space around the wood fibers is filled with gas, not water like most plants. When the temperature drops, this gas contracts, making space for the sap laden with sugar in between the cells. So water can move upwards from the roots by capillary action without the benefit of transpiration from leaves. This water freezes at night between the cells.

The day brings warm temperatures, melting this ice and expanding the gas, forcing water down the branches into the stems and trunks of the tree. The taps put into tree trunks to collect sap pierce the xylem all this sap is moving through, and water flows down the tap into the bucket or plastic line.

Interested biology students should read another blog, The Botanist in the Kitchen, http://botanistinthekitchen.wordpress.com/2013/03/18/maple-syrup-mechanics/ , and a cool roadtrip would be the Proctor Maple Research Facility of my old school UVM.

 

Free Tree Pruning Webinar

Categories: Midd Blogosphere

There are no truly awful times to prune a tree, but it’s best to prune in late winter. Early spring would be the only bad time-opening buds and blooms are the low point in a tree’s stored energy reserves, and late winter is warm (ish) but with the leaves off one can still see tree structure well.

So what I’m saying is that, based on the way this winter is going, we’ve got plenty of time left to prune. I’ve written about tree pruning before, but here’s a great opportunity to learn from an expert. The Vermont Urban and Community Forestry program is hosting a series of webinars during lunch hours on tree care, and the first is this Thursday. Tune in and watch V.J. Comai, owner of the South 40 Nursery, talk about tree pruning. Middlebury has bought many of his trees, and, (disclaimer!) he’s a good friend of mine. And truly masterful at the art of tree growing.

Here’s the published blurb-

The Basics of Tree Pruning- March 27th, 12-1pm

When is the best time to prune? What is the proper way to make a pruning cut?  What considerations should you make and what knowledge should you have about a particular tree before pruning?  This webinar will cover benefits of pruning, basic pruning techniques, tips for making a proper cut, and tools and tool safety.  Open to novices and professionals alike!

I highly recommend watching. Sign up at https://vtucf.wufoo.com/forms/tree-planting-pruning-webinar-series/ 

Middlebury’s Elm Collection

Categories: Midd Blogosphere

Among various tree geeks in New England Middlebury is well known for our Heritage Elm Collection. Elms, of course, naturally succomb to Dutch Elm Disease if we humans aren’t very proactive. We treat 28 old Elm trees, some of which are over 150 years old. I’ve written a couple new pages on them, one a general overview of all of the elms, one a brief primer on Dutch Elm disease and how we maintain the trees, and a final page on the history of the elm tree at Middlebury.

12-Elms

Elms have that classic umbrella shape, but can vary from specimen to specimen. We are fortunate to have trees in a wide variety of sizes and shapes, from the low spreading type like the Dog Elm behind Munroe (yes, we’ve named some of them), to the spectacular high and arching Field House elm. We also have been planting disease resistant varieties, such as Accolade Elm.

I remember a conversation with one of our seasonal employees several years ago, and we were discussing the difference between botany and horticulture. He cited the elm as a good example. Botanically, we will always have elm trees. They don’t die from Dutch elm disease until past their reproductive years, so they will always set seed and produce more young. And looking at them from a geological time perspective, eventually they will develop resistance, although that may be many millennia. Horticulture, though, is as much art as science, and as horticulturists we preserve some of the grandeur of an old elm, and we remember the dignity of the old shade tree as it was, even as we work towards bringing them back.

Tree Map Updated

Categories: Midd Blogosphere

Having run inside, fleeing from the sub zero temperatures outside today, I spent the day updating our ArcGIS tree map with all the newly planted trees this year, as well as our removals. Seems like a good time to point towards the Campus Tree Map page, or go/treemap. The latest map contains all the trees we individually manage on campus, nearly 2500. Maybe if the cold spell lasts we’ll come up with a smartphone compatible tour…

Water, water everywhere

Categories: Midd Blogosphere

So we had some rain today.

January is starting out with a bang-it didn’t get above 0 degrees for several days last week, and this morning was 50 degrees and raining. Rain of biblical proportions, with the rain gauge at the track saying .88″ of rain, most of it falling between 7:30-10:30, up to a half inch an hour at times. I’m not going to answer the Middbeat question of “What’s the deal with the weather”, except to say we’ve got some lower atlantic moisture sliding up the coast on the side of the polar vortex in the middle of the country. When low pressure systems like that get squeezed on the sides by intense high pressure, all sorts of funky things happen, like lots of quick rain, or high winds. We had both.

And with the deep freeze last week, storm drains were plugged, iced over, or covered in snowbanks. Rain can’t soak into frozen ground, taxing storm drains even when they are available and working. The landscape department went into overdrive, breaking up ice dams and opening storm drains. The most worrisome spot was solved quickly, that of Voter basement. You know, (or maybe you don’t), that place with all the computer servers. That would be a heck of an excuse for a banner web crash, wouldn’t it?

The northwest door of McCullough, the one that heads either straight towards Munroe and Mead Chapel, or head up the stairs towards Stewart, sits at the bottom of that whole slope below Mead. That entire side slope seems to drain right towards that door. There are several storm drains near there, including what turns out to be a critical one to the right of the door way. This is Jaime and Buzz, wearing hip waders, looking for the storm drain with ice picks and an iron bar. (As always, click on the picture to enlarge)

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And this is the doorway in question, where water was flowing a foot deep through the doors and down the stairs. We actually got the backhoe in there and broke up the iced over snow banks around the entry, and got the water moving down. The plastic and snow was acting like a temporary dam blocking some of the water.

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The Gamut room, in the Gifford pit, started flooding too. That’s Buzz and Jaime again, looking for the tiny little drain somewhere at their feet.

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Yes, I’m the one taking all these pictures. Only barn boots, no hip waders, and I don’t know how to swim.

The drain for this pit is simply down the hill below Mead Chapel. Bet you’ve been sledding over the top of it. Broke the ice around this drain and the pit was cleared in about 15 minutes.

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The last spot we’re still worrying about is on the north west alcove of Battell. This drain is frozen solid, barely flowing at all. We use bags of calcium chloride, and dump them on top of the drain. It acts like a non toxic drain cleaner, flowing down the drain and melting the ice. I’m hopeful this drain will be fixed by tomorrow. I’m not the most patient person you know.

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The true heroes for the day, though, I don’t have any pictures of. There is an entire custodial team known as ‘floor crew’. I don’t even know how many of them there are, but the ones I know on it are all pretty cool. They ran around all day with wet vacs, carpet extractors, blowers, mops, and various other implements of mass destruction. Wherever water was pouring into basements or doorways, they were there, fixing the mess, saving the floors and buildings (and maybe your room!) from the water mess.

 

Blind Sidewalk

Categories: Midd Blogosphere

Landscape architects sometimes speak of ‘desire paths’-a phrase that means exactly like it sounds. Laying out sidewalks, driveways, or trails is considerably harder than it looks. A budding architect can either be a hero for guessing exactly where pedestrians want to walk, or a goat for taking an urban mentality and assuming people will use the sidewalk regardless of location.

Try as we might, the Middlebury campus is full of desire lines. Some are an easy fix. Two new sidewalks cut across the top of the Atwater quad based on dirt paths that had appeared post-construction based on pedestrian traffic flow. One that couldn’t be done, a dirt path from the Johnson Parking lot to Atwater dining, we tried to block with trees and shrubs, but the desire remains unabated. Another one that concerns us is a dirt path from Battell Beach heading toward Milliken Hall. This cuts in a straight line up slope, and is becoming so worn down that it may soon start to erode.

Dirt path behind Allen Hall

Dirt path behind Allen Hall

A new desire path appeared after the renovation of The Axinn Center at Starr Library. The northeast corner of the building, down by Route 30, houses several large classrooms, and students cut across the quad from the Main  library down to that corner.

Not that we blame the pedestrians. It’s cold here. Getting from point A to point B as quickly as possible makes campus life a little more tolerable in January and February. It’s a pretty obvious place for a walk, but the problem is the other walks in the space.

Before my time, the walk ways were redone, and came out beautiful. This is landscape architecture at it’s best. Gently curving paths arc across the space, connecting the buildings that surround the quad. The brilliance of the plan is the fact that they work. In colder climes like ours usually corners are cut, curves straightened, and shortcuts abound. The desire line from the library to that corner was, as expected, straight, and pouring this as a walk would break the beautiful rhythm of the rest of the walkways.

pathways plan view

Then, after one winter storm, the path was beaten through the snow, this time gently arching around some trees, eventually meeting the walkway to the library.

pathway zoomed

With this proof of concept, we were off and running. Last summer we went out to the quad with surveyor flags, and marked a potential route. Some language school students became willing test subjects, and we tweaked the lines for an hour or so until it flowed right.

The other, even more subtle brilliance of the walkway layout in the library quad is the way the sidewalks are blind, hidden from view. I bet few people have noticed this, but a picture makes it obvious.

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View from Route 30

Looking up from Route 30, the quad appears to a large expanse of lawn, unbroken by walkways. The art is in the subtle placement of the walkways. All of them are slightly built up on the route 30 side, and pitch towards Old Chapel Road. Leaning the other way, the flat expanse of the walk would be visible, but the design at present allows them to be blind, not seen from the road. Obviously that couldn’t be done had the road been higher than the quad, but geology and geography was on our side this time.

The new walk was tricky to match this effect. Its placement across the quad required some elevation of the surrounding area, as well as some grading to continue the natural water flow across the lawn. Had this been interrupted the sidewalk would pool water and turn into an icy mess.

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The Butternut Seed Orchard

Categories: Midd Blogosphere

I’ve learned this summer a wonderful way to get attention is to build a one acre, 8′ high deer exclusion fence out on South Street past Eastview, brush hog down the existing corn, and not tell anyone what we are doing.

The landscape department, working with the State of Vermont, the US Forest Service, and a local researcher from UVM (Dale Bergdahl, father in law to local Middlebury College hero Mike Kiernan) applied for and received a grant from the Vermont Department of Forest, Parks and Recreation to erect the fence to grow Butternut trees. Butternut is threatened by Butternut Canker, a fungus with the potential to wipe out all Butternut across the United States. When found, disease resistant trees are grafted and grown for seed. An orchard was already established in Brandon, but another in a different locale (geographical as well as horticultural) is always preferred.

Deer love young butternut trees, hence the fence.

I’ve written a large explanation on the project on the blog here, it’s an entire page-Butternut Seed Orchard. I should give profuse thanks to Barbara Schultz, the forest health program manager in the Vermont Dept. of Forests, Parks and Recreation for an immense amount of work to make it possible,  Chris Casey  of the US Forest Service and Tom Simmons of the Vermont Dept. of FPR. And also, most importantly, local volunteer Sally Thodal for helping plant Butternut trees on one of the hottest days of the year.

Feel free to email any questions you have, and say hi to the trees as you drive by.