Trees in an urban forest such as ours are under more stress than in a natural forest environment. Granted, they adapt well, growing wide, as they don’t have their brethren next to them breaking wind (wait, that doesn’t sound right). They rely on each other for support, protection, and for all we know, companionship. Trees on campus get walked upon, climbed, swung from, and occasionally cut into with an axe. Root systems are walked on, soil compressed, all sorts of little indignities befall a campus tree.

Most fight valiantly, but, sadly, some succumb. It’s our job to remove the victims before they fall on something like a building, or, more importantly, someone. In arboriculture, a hazardous tree is defined as a tree that can fall on a target. That means if a tree falls in the woods, it doesn’t make any noise, because there is no target. Many trees on campus have targets-students seem to walk everywhere. So we worry. And cut the occasional tree.

Middlebury College has a vigorous tree planting program. It’s necessary in an urban forest to be continually replacing trees, much like succession in the woods. It should be on-going, as a mixed age population is more sustainable. We aim for diversity as well. No more than 30% of the trees in an urban forest population should come from the same plant family, no more than 20% from the same genus, and no more than 10% from the same species. We’ve been planting trees all along, but also removing some. So, we wondered, what was the karma factor here, were we planting more than removing?

I spent my lunch break looking at pictures of removals, and going through my planting files, worried about our department’s karma. Happily, we’re good, and by quite a bit. I’m in my fourth year here, three growing seasons, and in that time our department has removed 37 trees from the main campus. This does not include 5 or so lost to student damage, and a couple “weed” trees growing out of woodlines. We have planted over 128 trees, for a ratio of better than 3.5 to 1.

We were chopping leaves. It’s really the ideal way to recycle leaves, to put them back into the ground from whence they came, as it were. A Michigan State study found no discernible difference in chopping the leaves into the turf, or hauling them away. (Ever read turf research? They assign “quality ratings” on “turf color and density”. At my house I just aim for green and hope for the best…) As you would expect, potassium and phosphorus were slightly higher in the mulched plots, with no nitrogen change. They didn’t, however, test for soil organic matter, that holy grail in our Champlain Valley clay. Some of the guys in our shop saw Charlie Nardozzi on the Channel 3 news talking about how earthworms literally draw the chopped leaves down into the soil.

Michigan State recommends mulching leaves every week. We concur, especially after sending someone to one of our test spots with a four inch layer of leaves-poor guy was up there mowing, and mowing, and mowing. Your hands  are motionless on the steering wheel of the mower, so even in this glorious weather it’s cold.

I haven’t thought about, or done the math for the fuel savings/use for chopping versus blowing, hauling, and composting. I guess I’ll plead to being a tree guy on this one, and say that having the leaves mulched in place is much better for the trees and soil, and if it’s a little more carbon intensive than blowing, well, tough. I’ll bet it’s close to a wash anyway.

Before Leaf Chopping

After Chopping

I’ll post a third picture in the spring. Anyone recognize our super secret testing location?

I have the pleasure of occasionally working with Professor Helen Young’s Plant Biology class, and she has a wonderful Community Service Project component to her class.  For 10 hours or so in a semester, groups of students do some community service related to plant biology. We had one of the groups jump on the idea of the comment and do some seed collecting of natives. (More on the other groups later-I am always amazed and astounded at the dedication and high quality work I see from all the students I interact with.)(And they’re all smarter than to end a sentence in a preposition like the previous one I just wrote…)

Elissa Bullion, Catharina Grubaugh, Miriam Johnston, and Anne Runkel collected seeds from 29 native plants growing around Middlebury College. The work involved identification, collection, and quite a bit of research into the murky and conflicted field of seed germination and propagation. I have sitting in front of me a 15 page report on all the seeds collected and their germination requirements, along with a large envelope full of packets of seeds. Collection locations included Emily May’s pollinator garden at Bi-Hall, Ridgeline, the Garden of the Seasons, behind Ross and Atwater, the Atwater Roof, and the organic garden.

Local provenance is important in wildflowers, particularly in marginal species. The students were even smart and nice enough to collect seeds from several sources and several locations when possible, furthering the genetic pool. The plan is to grow the plants in the greenhouse this spring, probably in 50 count plug trays, and plant them out in the no-mow zones after our first cut in May.

The easiest one is smell. And the culprit would be the seeds.

Ginkgo Fruit

The tree is dioecious, meaning they have separate sexes, male and female trees. All horticultural literature describing Gingkoes state to plant only male, or fruitless trees. Why? The females bear the fruit, and, only clocking in at about 1 to 1 ½” long, the size belies the potency.  The fruit are covered by a fleshy apricot colored outer layer, called a sarcotesta. While it may look edible, the nose will give it away. The flesh contains butyric acid, which some describe nicely as “rancid butter”, but could more properly be defined as, well, people walking nearby a female tree with ripe fruit dropping to the ground tend to check their shoes to see what they had just stepped in, like some recalcitrant dog had just been on the same sidewalk.

Ironically, the seed or seeds hidden by the flesh are edible. The nut-like seeds are a traditional Chinese food, especially at special occasions, such as the New Year or at weddings. Some also claim aphrodisiac qualities-clearly not involving the fleshy outer coating. Quite attractive hanging on the tree, the fruit is best enjoyed from afar. One of the landscapers here at Middlebury accidentally got some of the fleshy part of the fruit on his jeans-he threatened to go home for the day.

Ginkgo is called a living fossil, and with that comes the challenge of explaining time. Relatives of Ginkgo date to Permian time, about 270 million years ago. The actual genus Ginkgo appears in the fossil record in the early Jurassic period, 190 million years ago. Stegosauruses were walking around underneath the trees (they weren’t grossed out by the smell) Time wise, the early Jurassic was when the single supercontinent Pangaea broke up into two-the northern Laurasia and the southern Gondwana. The Gulf of Mexico was just formed, and we’re still a long ways away from anything we’d recognize today as a modern continent. The only real way to relate the age of this is a bit of a stretch-the stone making up Wright Theater is 450 million years old.

The extreme age of the Ginkgo explains how it is a gymnosperm, (naked seeds, not protected by an ovary wall), like all conifers. It predates all the flowering plants in the world (angiosperms). The first flowering plants appear about 140 million years ago, and weren’t really prolific until 100 million years ago, and became the dominant type of tree at a relatively young 70 million years ago.

Ginkgo by Painter Hall

Have Gingkoes survived for 190 million years? Some of their ecological characteristics would make it seem possible, while others not. It’s slow growth, huge seeds, and shyness about reproduction (doesn’t start until relatively old, at about 20-30 years) would suggest that the cards are stacked against it in the cruel world of evolution. Ginkgo does, however, favor disturbed stream side environments, and has adapted to this niche, by bolting, or growing for many feet straight up before branching, and by clonal reproduction, growing new trunks from buds on the trunk, coppicing itself. This allowed it to out-compete the other stream-side dwellers, such as the ferns and cycads. This also explains its gradual loss to flowering plants even better adapted to the disturbed environments then our Ginkgo friends.

Even the possibility of its existence “in the wild” is called into question. On Tian Mu Shan (Tian Mu Mountain) in Zhejiang Province, China is a large population of Gingkoes growing in the woods surrounding Kaishan Temple. Some believe the trees are offspring of plants cultivated for the last 1500 years by the temple monks. In Conservation Biology, Vol 6 NO. 2, Peter Del Tredici, Hsieh Ling, and Guang Yang wrote about counting 167 Ginkgos in the 1018 hectacre preserve, and resolved that wildness is an impossible debate to solve. There was no evidence of smaller self-seeded Ginkgoes nearby. However, the conditions weren’t right, as Ginkgo does not seem to reproduce in the closed canopy of a mature forest.  The question should be that if Ginkgo has been around for 190 million years, shouldn’t they be forgiven for slacking off for the last 1500 years?

Many of the trees of Tian Mu Shan were multi-trunked specimens. Gingko is unique for its development of basal chichi, buds that form at the base of the trunk in response to wounding, tipping, or soil erosion. These can form entirely new clones of trees, offshoots of the parent, and explain a large reason the existence of Ginkgo for its long life span.

Closer to home, Ginkgo is a lovely tree, growing about 50-80’ high, although 100’ isn’t surprising. Width can vary tremendously, from 30-40’ to actually wider than tall.

Ginkgo Bark

The light grey bark becomes deeply furrowed with age, accented with dark brown.

Ginkgo Leaf

A common name is the Maidenhair Tree, named after the Maidenhair Fern, both having lovely fan-shaped leaves, and both, ironically, bright green. The leaves of the tree are about 2-3” long and wide.

Ginkgo Fall Color

Fall color can often be a spectacular yellow, although the leaves are susceptible to freezing and falling off the tree before coloring, like this year. Another unique trait is the fall habit of dropping all of the leaves at once, seemingly overnight.

Michael Dirr lists over 76 cultivars of Ginkgo in A Manual of Woody Landscape Plants. I own a “Chi Chi”, which reputably will grow into a rounded globe 10’ wide. I planted it too close to a path.

Gingkos are all over campus. My personal favorite is a couple houses north of Public Safety, almost right across from Storrs Avenue. Others are near Warner Science, Painter Hall, and on a sidewalk near Mead Chapel heading toward McCullough.

We don’t really like them either. They are heavy, not the most ergonomic of things to lug around, and they’re noisy. Necessary? Absolutely. Spend half of an hour in communion with a rake, and you’ll quickly understand exactly where your shoulders are, how they are supposed to move, and why it is just not possible to rake all day, or even part of a day.

Mulching leaves is a great option, and something we do as much as possible, by putting special blades on the lawn mowers. This is the ultimate in recycling-putting the leaves right back in the ground from whence they came (sort of). Unfortunately, many of the trees on campus have large leaves, and tend to drop all at once, which quickly overwhelms the ability of the mowers to chop the leaves. So we pick them up, using large vacuums, and take them to compost.

The no-mow areas are a great help this year as well. We are not picking up leaves in those locations at all, so that’s a significant amount of area we don’t need to cover anymore.

I was going to write about emissions from leaf blowers, but after some quick research on the web I decided not to even go there. It’s polarizing, to say the least. Proponents were quick to point out that all emissions from leaf blowers in use for one year equal the emissions form call cars in use for 11 hours. Opponents state how up to 30% of the fuel goes out the exhaust unburned (side note-that is on older models, not the ones we use). Regardless, after having just attended the local 350.org International Climate Day of Action, I’m feeling a little guilty, but realistic. They are tools, and a safe and efficient one, but one we would like to use as little as possible. We enjoy our work, and would like to keep doing it for a while, so we need to keep very good care of our shoulders.

We as a department have been phasing out our older models, in favor of more fuel efficient, and much quieter models, not just for the environment and the Middlebury community, but for us as users. The model we are switching to is a low emission, fuel efficient model with the lowest decibel rating on the market. They are so much more pleasant to use, in fact, that they are often the only ones in use.

So sorry about the noise, we’re not crazy about it either. We’re trying to get through it as quickly as possible. We’ve got snow to start thinking about.

Witch Hazel in Bloom

The line between tree and shrub can often blur, so I expect some grief from calling Witch Hazel a tree. One in Hartford, Ct. recently clocked in at 20 feet tall with an 18″ trunk, and I’ve read of one in the Virgina Appalachians with a 30′ spread and a trunk circumference of 52″. In reality, it is a very large shrub, with older specimens forming clumps of small trees.

And it is in bloom now. Not a mistake, its normal timing for bloom is when the leaves start falling. This leads to one common criticism of the plant-the fact that it blooms while the leaves are still on, hiding them. As you can see from the accompanying pictures, this doesn’t seem to be a problem this year, nor was it in the previous one.  Four bright yellow ribbon like petals extend from the center of the flower, a perfect one containing both male and female parts. Pollination is done by insects on warm days, but the flowers are also capable of self-pollination (wise insurance this time of year). The pollen remains in the ovules until spring when pollination officially occurs and the seeds start to develop. The joy of fall blooms is the lack of heat to blast them off. The flowers are effective on a witch hazel for at least 3 weeks. It is also the only woody northern plant to flower and have mature fruits at the same time. The woody capsules hold the seeds until late fall, and then utilize my favorite seed dispersal method, explosion. Splitting open in four, the seeds go for up to 30′. Cardinals and ruffed grouse are said to feed on the seeds, as well as turkeys and squirrels.

Witch Hazel Flower

Fall color of the leaves is a yellow gold, but not particularly bright. In the growing season, the leaves have been described as “lettuce green”, but we’re talking iceberg here, not a rich romaine. The shape resembles that of the hazels, hence the common name. Native to most of the east, except the colder areas of Vermont, Maine, and New Hampshire, the witch hazel favors wooded shady sites, but will thrive in sun given protection from severe drought and/or heat. Twigs, stems, and inner bark contain astringent properties, and it is this plant that is the source of Witch Hazel extract in drug stores. The forked stems are also the preferred wood for dowsing rods.

Some Witch Hazels can be found on the east side of the Axinn Center, in the Garden of the Seasons, in Ridgeline, and at 97 Adirondack.