A Bluebird Day

I try to make a point of getting out into the T.A. Forest at least once a week during a prep block to check trail cameras and note any new happenings in the woods. While walking on the Eastern Trail on a recent warm afternoon, I spotted a small flock of eastern bluebirds (Sialia sialis) feeding along the wood line. Bluebirds are insectivores who generally don't show up until insect numbers are sufficient in the springtime. There are always early arrivals and a select few that will actually hang on for the winter here in Southern Maine. I had a small flock hang around my feeder persisting off suet and sunflower seeds last winter.

The flash of blue from the male against the drab early spring landscape is hard to miss and I was excited to see this omen of spring. The timing of the sighting also lined up well with some vocabulary we have been learning in Maine Fish and Wildlife class. Sexual Dimorphism occurs when there is a distinct difference in appearance between male and female members of the same species. Eastern bluebirds are a classic example of a bird exhibiting sexual dimorphism. Mallard ducks, northern cardinals, and wild turkeys are all examples of Maine bird species exhibiting this trait. As with most sexually dimorphic birds, the male eastern bluebird is more brightly colored. It is assumed that this difference in appearance is a result of tens of thousands of years of natural selection. Females selecting for the bluest of males have created the intense coloration seen today. Because females do the choosing, their coloration has not become as intense as the males'.

 A female eastern bluebird perched on a branch above the Eastern Trail

A male eastern bluebird perched on the eastern trail field fence watching for insects along the ground

Crunch Time: Finishing Your Maple Syrup

Nothing strikes fear into the heart of a maple producer more than getting side tracked in the final moments of syrup production and cooking sugar onto the pan. This not only makes a mess that is hard to clean up but also can ruin the flavor of your entire batch. With the amount of preparation and manual labor that goes into sap collection and boiling, losing the batch at the final moments can be devastating. During my high school and college days working at Snell Family Farm during maple season, boiling was an evening ritual that felt like a reward for hard work earlier in the day. We would spend the evening stoking the wood fired evaporator and telling stories. As the thermometer in the finishing pan began to creep toward 219 degrees Fahrenheit (the boiling point of syrup), things got considerably more serious. The finished product had to be removed from the heat and filtered immediately or else BAD things could happen.

A close eye is kept on the thermometer in the final moments of syrup production.

I "finished" our first pint of syrup in class this past Monday and we were all able to enjoy warm maple syrup over ice cream. Saying syrup boils at 219 degrees Fahrenheit is a little oversimplified. In fact, maple syrup boils 7.1 degrees Fahrenheit above the boiling point of water. We generally think of the boiling point of water as 212 degrees Fahrenheit but this is a moving target. Elevation and barometric pressure can affect the boiling point of water and thus move the syrup target up or down.

Using they hydrometer to confirm our syrup is finished

Sap that has not yet reached the sugar concentration required to be called syrup can spoil quickly so it is important to confirm in a couple of ways that the syrup is truly finished. Another measurement that can confirm we have reached syrup is density. A nifty little tool known as a hydrometer uses principles of buoyancy to measure the density of a fluid. Maple sugar producers use a hydrometer calibrated for syrup to help confirm their product is finished. After hitting 219 degrees Fahrenheit in class, we tested our syrup using a hydrometer and confirmed we were done.

Filtering the final product

Finally, the hot syrup was poured through a filter consisting of a synthetic filter paper and multiple layers of cheese cloth. This removes all of the mineral, mostly potassium nitrate, that has concentrated in the syrup along with the sugar. Maple producers call this cloudy mineral sugar sand or niter. Finished syrup should be free of sugar sand and bottled hot to ensure there is no contamination in the container. We let our new jug of syrup cool for a few minutes before enjoying a long awaited taste of spring.

A sweet reward

The Finished Product

Thursday was a long day of boiling but with a sweet reward when all was said and done. I got our mini evaporator set up just below my classroom window first thing in the morning. I teach freshman chemistry during first block and this process provided a great teachable moment. The timing of the boil could not have been more perfect as we are currently learning about classifying matter and separating mixtures. I presented them with a 5 gallon bucket full to the top with what looks like water. It took a little convincing but they eventually believed me that around 2.5% of the bucket was actually sugar! After a bit of brainstorming, their experiment was in place. Maybe, by boiling the sap, we can remove the water leaving the sugar behind? Perfect, it was out the door to start our boil. I can't lie, it was a little anticlimactic after dumping the cold sap into the pan and standing there for a few minutes staring at a lifeless pot. I can't wait to show them the finished product first thing Monday morning.

Raw sap just after collection earlier last week. (Photo by Julie Vail)

Before long it was second block, my Trees and the Maine Forest upperclassmen were arriving, and the pan was rolling. At this point in the boil, the sap was still very dilute but their was a faint yet familiar smell rising from the steam. We had a great time standing around the pan in the ice cold breeze talking about the ins and outs of maple production.

Steam rises from the pan during our first boil of the year. (Photo by Julie Vail)

Over the course of the day, the sap level in the pan would drop and more would be added. Slowly, the sap began to darken and the steam began to smell sweeter and sweeter. Sometime around the end of third block I was able to bring what was left inside to finish boiling in my classroom. People were following their noses into the room to find the source such a sweet aroma. I was bottling finished maple syrup just as the final bell rang. Stay tuned for a post detailing the finishing process.

Our first batch of syrup this season.

The Sap is Running

"Sap's Runnin'" is a comment heard all over the state during this time of year. Our recent warm days and nights below freezing create the perfect conditions for pressure to build up in the sapwood tissues of our resident maple trees. The warm days increase the pressure within the tree forcing sugar rich sap upward toward the crown where it will be used to fuel the production of this year's leaves, flowers and fruit. Cold nights cause a decrease in pressure within the tree pulling water in through the roots and setting up the next day's sap "run". The sugar within the sap was produced the previous year through photosynthesis within the now decomposing leaves, then stored for the winter in the tree's roots. In a way, when you sample some real maple syrup, you could say you are tasting some of last year's sweet sunshine.

Trees and the Maine Forest students tap a campus maple.

Maine is the third largest producer of maple syrup in the United states although our production here in the U.S. is dwarfed by that in Canada who produces 75% of the global supply annually. I worked each spring as a high school and college student collecting sap and producing maple syrup at Snell Family Farm in Buxton and enjoy passing on this springtime tradition to my students today.

The sap began running as soon as the spile was inserted into the tree.

We recently tapped a couple of sugar maple (Acer Saccharum) trees right here on campus at T.A. While there are no wild sugar maples large enough to tap in the T.A. Forest, there are two large specimens growing right on campus that were most likely planted decades ago. Nearly any species of maple can be used to make syrup but sugar maple is preferred due to its higher sugar content and fine flavor. Sugar maples generally produce syrup at a 40:1 ratio. This means we will need to collect about 5 gallons of sap in order to produce a pint or so of syrup, just enough for an ice cream party. It will take hours of boiling to remove the excess water and achieve our tasty reward. Stay tuned for a post detailing the boiling process.

A sap collection bucket hangs on an old campus maple.

Fresh Snow Makes for Great Tracking

Our recent light snowfalls have made for great tracking conditions in the T.A. Forest. An inch or so of snow is all that is needed to document the passing of winter wildlife. Any more than a few inches can make determining the species that left the tracks much trickier. On our latest trip outdoors, my semester 2 wildlife students were treated to a variety of tracks on and around the eastern trail. Gray squirrels have expectedly been out and about on the warmer days, visiting our feeders and digging for acorns buried last fall.

Gray  squirrel tracks in the T.A. Forest

A big part of identifying a track is understanding the way each creature walks, also known as gait pattern. Maine mammals can be broken into four distinct groups including diagonal walkers (dogs, cats, deer), bounders (weasels), gallopers (squirrels, rabbits), and striders (bears, raccoons, porcupines, skunks). The gray squirrel is a classic galloper in that its hind feet often land ahead of its front feet as it runs. The tracks seen above are typical of this gait pattern. It can be hard for beginners to decipher which direction a galloper was headed as we expect the larger hind feet to be in the back. Careful observation of the direction the toes point will clear up any confusion. The squirrel tracks shown above point to the upper lefthand side of the frame. 

 Raccoon tracks in the T.A. Forest

Our most exciting discovery last week was this fresh set of raccoon tracks meandering from one squirrel feeder to the next. Raccoons spend much of the winter in den sites resting and living off of fat stores built up the previous fall. However, any warm snap will bring them out in search of an easy meal. It was neat to get to see such perfect prints in the dusting of snow. This is a great representation of a "pacer" gait pattern as each foot lands in its own spot unlike diagonal walking foxes and coyotes whose hind feet land perfectly in the tracks created by their front feet.

Invasive Plant Species

Invasive plants are non-native species whose introductions can have negative economic or ecological impacts. Unfortunately, some of these species are becoming common on the Maine landscape. Invasive species often outcompete native plants creating monocultures that can require time and money to mitigate. These same species are often less valuable as wildlife habitat.

Multiflora rose hips

My Trees and the Maine Forest students have been studying invasive plant species this week. We spent the class block searching the T.A. forest and identifying as many invasive species as possible. It was eye opening to see just how many of these once ornamental plants have escaped and begun to grow wild along the Eastern Trail. In all, seven species were identified within sight of the trail in less than a quarter mile.

Japanese knotweed along the Eastern Trail

Areas of recent disturbance are the most common places to find invasive plants. Many of them are early successional species perfectly adapted to grow quickly and outcompete the native plants around them. In their natural home ranges, these same species are much less pervasive. Here in North America, they lack the predators and disease that our native species have to deal with. Several of our common invasive species produce berries that can be valuable winter food for songbirds and small rodents (see the common buckthorn below). Unfortunately, seeds are then spread great distances in bird scat creating new infestations.

Common buckthorn berries

Invasive Plant Species Observed 1/6/17:

• Muliflora Rose (Rosa multiflora)
• Shrubby Honeysuckle (Lonicera sp.)
• Japanese Knotweed (Fallopia japonica)
• Norway Maple (Acer platanoides)
• Asiatic Bittersweet (Celastrus obiculatus)
• Common Buckthorn (Rhamnus cathartica)
• Japanese Barberry (Berberus thunbergii)

F.I.G. Plot Setup

Yesterday with the help of district forester, Oliver Markewicz, my "Trees and the Maine Forest" students began the initial setup of a F.I.G. plot in the T.A. Forest. F.I.G. stands for Forest Inventory Growth and is a statewide program headed up by Project Learning Tree and the Maine Tree Foundation. This program encourages schools to establish long term plots in forests near their campus with the purpose of monitoring tree growth and patterns of change over time in the Maine woods. The ongoing data from schools all over the state is posted HERE. Our data should show up on the website in the near future. The students working to do the initial setup of this plot have the honor of starting something that will continue long after they have left Thornton Academy. It is neat to think about the possibility of their children someday taking my class and performing the same measurements on the same trees in what should be a much different looking forest.

Students have spent the first half of the semester working hard to practice identification of 25 common southern Maine tree species as well as master the measurement techniques used daily by foresters and loggers. Our F.I.G. plot is circular with a radius of 37.24 feet which amounts to one tenth of an acre. Beginning at magnetic north, students worked clockwise around the plot first identifying, then performing quantitative and qualitative measurements on all trees with a DBH greater than five inches. DBH stands for "diameter breast height" and is measured at 4.5 feed above the ground on the high side of the tree.

Students perform measurements on a young northern red oak under the guidance of district forester, Oliver Markewicz.