ecology

Squirrel Business

| Tim Parsons

I’m primarily a plant person, because I’m slow on the uptake and not very observant. Someone says “Look at that bird!” and by the time I’m looking even close to the right direction, let alone focusing in on what a bird is, said bird has flown far, far away. Trees, wildflowers, landscapes-easy to see, and prone to stay in one place. Since starting at Middlebury, though, I’ve become enamored of our extensive squirrel population.

Photo Credit-Dan Celik (Thanks!)

Aristotle named the squirrel ‘skiouros’, combining  two Greek words, ‘skia’ for shade, and ‘oura’ for tail, or, in some ancient Greek slang, ‘he who sits in the shadow of his tail’. The French created the word ‘esquirel’, from whence came the English ‘squirrel’.

Our breed of squirrel on campus is the Eastern Gray Squirrel, native to the east coast from Manitoba to Florida and eastern Texas. Squirrel fossils date back to 40 million years ago, and know number over 365 species in seven families, including ground squirrels, tree squirrels, and flying squirrels. Clearly, our Middlebury squirrels are tree squirrels. This time of year their nests, or dreys, are seen high in some of our trees, or in the several hollow trees we have scattered about.

We seem to have some squirrel ‘families’, or at least some serious inbreeding going on, although it does not seem to be as notable this year as in past years. While all white or black squirrels can often be seen in urban populations with little to no predation, up by Mead Chapel for the last several years we had a group of gray squirrel with thin, wiry red tails, more like a red squirrel. The difference in the squirrels between Mead Chapel and the library quad was quite striking. Now the Mead squirrels have fluffy tails, but they are still red.

Squirrels are ‘scatter hoarders’, making many small caches of food in various locations. They are known for their spacial memory, remembering where up to 1000 of these sites are. Food types are generally tree seeds, including many nuts, although they’ve been known to feast on fungi and tree bark as well. When food is scarce they will even turn carnivorous, eating insects, frogs, small birds, even other squirrels (!).

They are most well-known for feasting on nuts, however. In fact, their love of seeds started this post. While preparing to remove the lightning struck spruce, we noticed a large cache of spruce cones underneath the tree. Given a sudden abundance of a food source, a squirrel will make a temporary pile to await better burial and hiding later. Spruces were prosperous this year in cones, and if you’re a squirrel you can’t let a good thing go to waste. The seed of the spruce sits at the base of a seed scale, and each cone can have many scales. Squirrels seem to process the cones, flaking away the bracts to reach the seed, and then later burying the seeds for retrieval later.

 

If I were a squirrel, though, I’d be waiting for acorns. A good source of protein, their size is probably a meal unto itself. While humans don’t like the bitter tannins found in many acorns, the squirrel doesn’t seem to mind.

 

I remember my first fall here at Middlebury, and thinking our Red oaks had a terrible disease. The ends of the branches, the new growth, would lie scattered about the base of the tree. Dan Celik, custodial supervisor extraordinaire, has noticed the same thing, and took pictures for the blog. Squirrels, even though they have a brain the size of a small walnut, aren’t too dumb. They go to the end of an oak branch, and gnaw with their teeth until the end falls to the ground, where they can easily and quickly harvest the bundle of acorns attached.

Photo Credit-Dan Celik (Thanks!)

Japanese Beetles

| Tim Parsons

Gardeners, and especially Vermont ones, seem to like to share maxims. Like “Don’t like the weather? Wait 5 minutes.” My Nebraska wife said she’d heard that one out there too, so don’t go thinking that our weather is more strange in the Green Mountains. The one I was thinking of a couple of days ago was on Japanese Beetles, and their annual appearance on the Fourth of July.

It held true this year, at least in my yard, with a small collection of them on some wild grape leaves. They’re a particualry nasty little pest, as their voracious appetite can seemingly eat anything in their path. In reality, though, they favor certain plants above all others, but it would be a dreary yard indeed if you didn’t have at least one plant they found tasty.

Japanese Beetles were introduced in August of 1916 in the Henry A. Dreer, Inc. Nurseries, about 2 1/2 miles east of Riverton, New Jersey. Closed in 1944, this very famous nursery owned the very first plant patent, the New Dawn Rose, a climber still in production today. Rutgers and the U.S. Department of Agriculture made a valiant effort to control the spread of the beetle, including attempting to keep sprayed a half mile radius of land around the point of discovery with Arsenate of Lead. The beetles turned out to be strong fliers, and would quickly fly to un-sprayed foliage. Control efforts moved to containment, but the Beetle was too strong for that as well. By 1920 the beetle occupied 50 square miles of New Jersey, 213 square miles in 1921, and by 1925 was over 500 square miles. (Read about the complete battle at the Rutgers Department of Entomology.)

Japanese Beetle, Popillia japonica, are very recognizable and familiar to many of us working outside. It’s bronze colored back is a dead give-away, with a metallic green body. Harder to identify, but equally destructive, is it’s larval phase, a white grub in prolific in lawns almost 2 inches long. The grubs are strong feeders of turf roots, but most people complain about the turf damage caused by raccoons and other creatures digging for a fast grub meal.

They are clumsy fliers, dropping when hitting a wall (don’t we all?), so that’s how the ubiquitous traps work, by having four walls coated in floral scent and phermone to lure the idiotic beetle to fly into, dropping in the bag below.The traps work great, too great, a victim of their own success. Multiple studies have shown that the traps lure insects not only into the trap, but into the surrounding area, thereby increasing the population. The best place for a trap? The next door neighbor’s yard.

Control of the beetle is best done at the source, the grub stage, but is quite tricky in Vermont. The best organic control is Milky Spore, a Bacillius bacteria that kills the grub, and reproduces itself inside the body, spreading into the soil. Unfortunately, Milky Spore does not do well in heavy, moist, cold soils, namely all Vermont soils. While it is somewhat active at soil temperatures of 60 degrees, it does best at 80, a range rarely seen this far north. Anecdotally I’ve heard of treatment succeeding quite well, but it’s time and expense I can’t rationally recommend.

Other control recommendations seem to almost change yearly, so you’re on your own. I’ve had good luck picking them off by hand or dropping them into a mason jar of soapy water-they aren’t the fastest things in the world. Systemic insecticides work well, but our bee population would thank you if you stay right away from those.Neem, or even hot pepper oil, acts as a deterrent in low populations, although higher populations will ignore them like a teenage boy in a line for pizza.

Cedar Apple Rust

| Tim Parsons

Once you see one, you start seeing them everywhere.

Cedar Apple Rust-Juniper Spore Horn

The first warm rain in the spring makes these spores appear on Red Cedar (Juniper) trees, completing part of its life cycle. Red Cedar is a first-growth conifer pretty common in Vermont in abandoned pastures, along roads, and elsewhere, so finding these disgusting things aren’t hard. Sometimes they are as big as your fist, sometimes just a golf ball, but they are always bright orange, and disgustingly slimy and gelatinous. I remember being thrown one by my landscaper employer in Connecticut, and being grossed out for the entire rest of the day, catching it absentmindedly.

This is brought to you by a fungus called Cedar Apple Rust, latin name (brace yourself) Gymnosporangium juniperi-virginianae. The fungus is a ‘dual-host’ fungus, needing two different type plants to complete its life cycle. Part is on the Red Cedar, where small galls sit and lie in wait for the warm rain in the spring to activate. They can be mistaken for cones for those not totally up on their conifer botany. Once activated, spores then alight on the wind, and carry to apple trees (or crabapples), where they infect the twigs and leaves. On this host, it appears like small orange or yellow spots. These spots then produce spores in July or August, and re-infect the juniper.

Because of the ubiquity of Eastern Red Cedar control is very, very difficult. Like many things, the best techinique is prevention, which entails removing all cedar from within a mile (!) of the orchard. Fungicide sprays are effective, but need to be done now, which is another whole host of problems, seeing as the apples and crabapples are starting to bloom, a delicate time to say the least. Apples and crabapples vary in their susceptibility to the disease. I fell in love with a crabapple once, a double flowered variety named ‘Brandywine’, with dark pink flowers like tiny roses (I won’t post a picture and tease you too), only to watch it totally defoliate by the end of July-not a leaf left the rest of the year-all from a severe infection. Resistant varieties can be found, though, and are probably a good idea.

 

Pussy Willow

| Tim Parsons

Ask 20 gardeners, and you’ll get 40 or more answers on what they consider signs of spring. One of the most common answers, though, will probably be Pussy Willow.

Salix, the Willow family, claims more than 400 members, with a range from the tropics all the way up to being the last woody plant before you are stumbling across the Arctic Circle. Many kinds are native to western China,  including the magnificent but weak-wooded Weeping Willow, but North America claims her share as well, about 75 varieties. Pussy Willow is one of these, although there are several willows with that name.

Go to your local garden center, and you’ll probably find, well, you probably won’t find pussy willow at all. Garden centers have a hard time selling very early or very late bloomers, like pussy willow or Witch hazel. Both bloom before most garden centers this far north are even open, and, during the regular growing season, these wonderful shrubs probably wouldn’t even catch your eye.

Should you happen upon one, though, probably in the sale bin, odds are it is a Salix caprea, a European Pussy willow also know as Goat Willow. Native from Europe to northeast Asia and northern Iran, it is nearly identical to our native species, Salix discolor. Our native form is more susceptible to canker, and have deeper brown branches and a nearly bluish white underside to the leaves, but it is the canker scaring plant propagators from growing the native species.

Pussy willow (both) reach about 15-25 feet high, and about 12-15′ in width. Native to wet, moist areas, they are frequently seen in marshes, wetlands, and on the edges of rivers and ponds. The ‘pussies’ we are familar with in kindergarten are male catkins, flowers with inconspicuous or, like Salix, no petals. While most catkins are designed for wind pollination, the Willows are known for insect pollination. Perhaps the non-showiness of the catkins is forgivable in the wild, as nothing else is in bloom, competing for the insects to visit them. For you pollinators among us, they are high-sugar flowers. At any rate, they are easy enough to force in a vase starting in February for the spring-desperate.

In the wild, Pussy Willow is an important source of food for browsing animals, such as deer and moose, although not the most palatable (who asks?). Duck and other waterfowl feed on the catkins in the early spring, while mice and other rodents can be found eating the stems in the winter.

Majorie Harris, in Botanica North America, writes of the Pussy Willow, and references a somewhat sketchy web site for the legend of how Pussy Willows got their name. It’s a Polish legend, and involves a sad, crying cat next to a river, whose kittens had fallen into while chasing Butterflies,as kids and kitts are likely to do. Hearing their cries, the Willow trees next to the banks swept down, arching into the river and allowing the kittens to cling to their branches, when they were safely brought to shore. Every spring since, the willow sprouts tiny fur-like buds at the tips of their branches in remembrance.

We have some Pussy Willows at Middlebury, but I had to do some thinking to remember where. While there undoubltalby some wild native species along Bi-Hall Road or the wetlands next to the Johnson Parking lot, the best species on campus proper are probably right next to Atwater Dining Hall, on the south side, where they were planted in the ditch that runs along there as part of the storm water mediation.

 

Middlebury Becomes a Tree Campus

| Tim Parsons

I’m very (very) pleased write that Middlebury College has been named a Tree Campus for 2010, culminating work started in January of last year by the students in my Trees and the Urban Forest Winter Term class. Special thanks goes to two students in particular, Chelsea Ward-Waller and Hilary Platt, for being the driving force behind the application process, and for being strong advocates of our urban forest on campus.

I’ll quote from the letter we received-

The Tree Campus USA program is an initiative that sprang from a partnership between the Arbor Day Foundation and Toyota MotorNorth America, Inc., to foster the development of the next generation of Tree Stewards. The program is designed to award national recognition to college campuses and the leaders of their surrounding communities for promoting healthy urban forest management and engaging the3 campus community in environmental stewardship.

As you already know, trees are a vital component of the infrastructure in campus landscaping, providing environmental and economical benefits. Trees in urban areas, and especially on campuses, reduce the heat island effect caused by pavement and buildings. Leaves filter the air we breather by removing dust and other particles. Properly placed trees create a welcoming environment that makes students, administration,and alumni want to be a part of the campus.

Last year there were 74 Tree Campuses across the country,and this year there are 114. Middlebury is the only campus in Vermont that is a Tree Campus, and one of only two in New England. The older program, Tree City USA, has over 3400 communities, with 8 in Vermont, including Burlington and Rutland. We all can take great pride in our trees and campus landscape, and I enjoy being part of a team that places as much value as we do on our campus environment.

The standards to become a Tree Campus are designed to create a sustainable plan to care for and manage campus trees, and to provide opportunities to engage and educate college students and community members in tree planting, benefits of trees, and in Best Management practices. To be eligible for Tree Campus USA recognition, schools must meet five core standards of tree care and community engagement: Establish a campus tree advisory committee, evidence of a campus tree-care plan, verification of dedicated annual expenditures on the campus tree-care plan, involvement in an Arbor Day observance, and a service-learning project aimed at engaging the student body in sustainable efforts. Collaboration is encouraged-the program is a platform for students, faculty, staff, and community members to team up and learn from one another about the benefits of trees on college campuses. Ensures true sustainability of the urban forest by joining forces with the broader forest community.

Our service learning project was a high point in the entire process. Another group of students in the Winter Term tree class worked on a complete Street Tree plan for an area in Middlebury known as Buttolph Acres. This included an inventory of existing trees, recommended locations and varieties, as well as tree planting specifications. The students also used a computer model known as iTree to estimate what the potential carbon sequestration, storm water abatement, and pollution control the tree planting would yield in 25 and 50 years. The work they put into this is amazing-I highly recommend downloading it ( Buttolph Acres Proposal ) and reading it.

And yes, we’re planning a heck of an Arbor Day (May 6). Stay tuned!

Putty Knives

| Tim Parsons

A couple of storms ago, I caught myself absentmindedly sticking our most important snow fighting tool into my pocket, and it occurred to me I’d left it out of the list of techniques and equipment I’ve written about in the past. Yes, for some storms, the most important tool in our kit seems to be the lowly putty knife. I prefer an inch and half blade myself.

I was introduced to this my first winter at Middlebury, during the Valentine’s day storm of 2007. The roads were impassable- I’d tried with a friend in a four wheel drive truck, and we’d turned around and went back to the college to spend the night. This was no ordinary storm, but a a blizzard, so strong we couldn’t keep up with it, either by shovel, tractor, or plow. The most important work of the night remained, though, so we broke into teams of two or three, shovels and putty knives in hand, and trudged from building to building, closing doors.

A plumber told me Middlebury has 110 buildings. I asked him how many exterior doors were on campus, and got a look like I’d lost my mind. Fire codes dictate at least two per building, and some many, many more, so let’s say there is 500. Most of these buildings are heated centrally with steam, from the Service Building. The operators in there work wonders, 24/7, heating the entire campus. Ever had snow block your main door at your house, preventing it from closing? Even if you don’t notice immediately, I bet you quickly figure it out as the draft quickly goes through the house. Some storms seem block doors better than others. Now imagine if even a couple of doors on campus are like that. The magicians in the heating plant notice. Now imagine those storms where even 10% of the doors are stuck part way open. The steam can’t compete,alarms in the plant go off, and precious steam and heat literally goes out the door.

So we go out, putty knives in hand, cleaning door thresholds, making sure the door is re-sealed against the building. The knives scrape the snow from the threshold, and from the underside of the door. It builds up against the door frame as well. If you’re really unfortunate, or in the right storm, hot air from the building is melting the snow in the way, and it re-freezes to rock hard ice.

We’ll gladly do the shoveling, plowing, and salting. Save us some time, though, and close the door behind you. What, did you grow up in a barn? Snow stuck in the threshold? Grab a knife from the dining hall if you have to, I won’t tell Aunt Des.

Sustainable Landscaping

| Tim Parsons

While doing a post on the Sustainable Sites Initiative for the Atwater Landscape contest blog Turf Battle I’d remembered I also wanted to write about a homeowner version of this document called Landscape for Life. I first read about this project at the wonderful Garden Rant blog, then immediately went to read the document. I’d been following the work of the Sustainable Sites inititive for a while, and am over-joyed to see a less ‘industrial’ application.

Like the Sustainable Sites website, the Landscape for Life website is a great resource in an of itself, but the true reading is found in the large document, available for download. Highly recommended  winter reading for your inner gardener.

Leaf Color

| Tim Parsons

I’ve been reading quite a bit this fall in various newspapers, web sites, etc. about the science of leaf change, and I thought, well, heck, there goes another blog post. I don’t see the sense to retread ground others are covering.

By now, you’ve probably read that leaf color changes by the shortening of day-length light triggers the tree to begin shutting down the leaves, and that chlorophyll breaks down, and sugar is absorbing into the tree. In a nutshell, the veins connecting the leaf to the tree are closed (abscission layer), and once this is complete the leaf falls.

Weather does play a part in leaf color, and in the color you see in the hills as you visit your children on parent’s weekend here (Hi parents! Your kids are doing fine. They want more money.) Many articles have talked about warm weather delaying fall, cool nights are good, drought bad. It’s easy to understand, though, if you think of it in terms of plant health.

A happy, healthy tree in a good growing season will more than likely have pretty spectacular colors. The factors responsible for bad fall color aren’t good for the tree health either. Drought is bad for fall color, and also bad for the trees. Southern Vermont this year had a pretty bad late summer drought, and when I was on route 4 a week or so ago near Woodstock the leaves were terrible, turning brown and falling off, rather than turning nice colors. Here at Middlebury it’s been a dry September, and then the recent rain storms came at just the right time, and the leaves held on long enough to turn well. Warm fall days and cool nights? Good for sugar production, and the breaking down of chlorophyll in the active leaf. A late spring or a severe summer drought can delay fall color-the tree holding on to it’s leaves as long as possible, storing as much energy as it can before winter.

Another leaf color fact plant geeks have probably noticed is called the Leaf Wave Model. An article at the University of Georgia discusses this: Peak color is an opinion. Different trees turn at different times, and in differing colors. Yellows dominate early, then oranges as both later trees turn, as well as some yellow leaves becoming more orange. Finally reds dominate the landscape, with accompanying orange. Browns come last, generally in oaks. The leaves in Vermont are spectacular because of the forest cover types found here, yellow Ash, orange and red maples, along with splashes of green from Pine and Spruce. By paying careful attention to the mountains in the fall you can watch this leaf color wave happen.

Some other reading I’ve been doing this fall was about the color red, something I’ve never thought about. An interesting question for botanists has been “Why red?”.  As chlorophyll disappears from the leaf, the other colors emerge, such as yellows and oranges provided by Carotenoids. Red, though, is expressed through Anthocyanin, but is not found in a leaf, and must be produced. The question, therefore, becomes why would a plant be producing a compound, expending energy, at a time in it’s life cycle when it is trying to store and conserve? There are two schools of thought, and probably both are correct, some for some plants, some for others.

One theory is that anthocyanin is produced in trees in nitrogen poor soils. In some varieties of trees, as the green chlorophyll breaks down, the leaves are vulnerable to bright sunlight, and this sunlight breaks down the produced sugars, thereby not being absorbed back into the tree as energy storage. The red pigmentation acts like a barrier from the sunlight, allowing the tree to absorb more of the sugars it has produced. Nitrogen poor soils means the tree would have produced less sugars, being weaker growing, so more red pigmentation would conserve more of the valuable food.

The other theory is one of coevolution, that red leaves are a signal to insects as a repellent, a red warning signal to the insects attempting to use the tree as an overwintering site. A study has shown this in aphids and apple trees, that wild apple leaves turn red in the fall, and suffer less aphid predation.

No Mow Year Three

| Tim Parsons

Well, we mowed the no-mow again (loving the oxymoron), as it was due for its spring knockdown. Like I’ve seen in quite a few farmers fields this year, it actually wasn’t a great grass year-the clovers, alfalfas, and wildflowers seem to have been able to keep pace with the spring flush of grass growth this year. We do an intitial mowing in June (early July this year, rain) to prevent long grass from being availible for deer tick egg laying, as well as giving the wildflowers a fair shot at competing against the grass. Look around Addison County, at many of the hay fields. The second cut of hay is the attractive one, the one where the alfalfa and clover really stand up, while the grass plays second fiddle. Hopefully, it will be the same in our no-mow zones with wildflowers. This year, though, the wildflowers stood out with the grass, and some early ones had started to bloom. They’ll re-bloom, even after being mown.

Observant people will have also noticed that we slightly expanded some of the no-mow areas this spring. Facilities Services, in concert with the Master Plan committee, identified some areas next to existing no-mow locations that needn’t be mowed lawn. The insight of the Master Plan committee was great to watch. With a wonderful eye for design, they expanded no-mow almost right to the front door of Bi-Hall, further shrinking what we are beginning to call Bicentennial Park, making the park like area smaller, but more readable and usable. The same effect was done up by Hadley-Milliken-Kelly-Lang, bringing the no-mow area closer to the row of dorms, making a park like space for what we are now calling Ross Commons surronded by no-mow meadow. There is a bonfire pit in the middle of the commons now, as well as a volleyball net.

There’s a wonderful article, not availible online, sadly, in the May issue of Landscape Architecture that I’ve recently read, entitled “Graduating To Green”, by Mark Hough, ASLA. It starts “The traditional American campus landscape, captured most vividly by an image of open lawns with mature canopy trees, is one of our most established, celebrated, and significant landscape typologies and is, in the 21st century, at a crossroads.” The article is very interesting, and longer than I have time to write about on a beautiful summer evening, but maybe in the next rainstorm…

When Good Plants go Bad

| Tim Parsons

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