Author: Max Lutzius

The crunch of packed snow is reassuring as I cross over chapel pond, stories of trucks being driven over frozen lakes adding to my confidence in the tensile strength of ice. Admittedly, those stories ended in the tucks falling through the ice, but I try to not think of that. Seeing the shanties of ice fishing enthusiasts on the drive over, however, did make me question how anything could survive the winter freeze in a still body of water. Did fish hibernate through winter? Can they breath in their isolated world? Did they ever freeze solid? To me, it seemed a stroke of luck for aquatic life that the density of water does not react traditionally to temperature.

In fact, water is most dense at 4 degrees Celsius, unlike most substances that constantly increase density with falling temperatures. This means further cooled water will rise to the top, eventually freezing solid, forming an insolating layer between the denser, warmer water and the outside freeze. This layer of ice slows the exchange of heat between the body of water and atmosphere, keeping deeper waters liquid all season. In this capped world, food and oxygen are also trapped, but in lower quantities. Many fish, therefore, enter a state of reduced activity. A notable feature of this reduced state is the slowed metabolism, which allows a small amount of food to go a long way. This also allows some species of fish trapped in ice to keep themselves safe, producing a type of antifreeze in their bodies until the spring thaw!

While this smaller body of water has seemed to avoid the rush of ice fishing, Lake Champlain bustles with activity as groups try their luck for Northern Pike, Lake Trout and even Salmon, fooling their prey with rare food sources in the bleak winter season.

Photo credit to Laura

Pausing for breath after jumping a patch of thin ice, I take a moment to inspect my surroundings. The frozen wetlands are beautiful and still, seemingly devoid of life, and I snap a picture. Turning around to inspect the woods nearest to me, I notice a significant portion of a dying tree to be missing. Though it has shed all leaves or needles, the whorled limbs suggest it is an evergreen, likely an eastern hemlock given their prominence in the area. The cut seems similar to that of an axe, but neater and rounded, and I remember that wetlands are often created as a consequence of beaver dams. Excited about this discovery, but pressed for time, I make my way back towards the trail only to jump as I see a small rodent dart from one ice covered pile of sticks to another. The encounter with beavers confirmed, I hastily researched their habitats and lifestyles upon returning to campus.

As it happens, beavers do not hibernate during winter, instead spending the colder months with family in a warm lodge, the protected home built in the deeper waters of their flooded wetlands. Closer inspection of my casual photo reveals several of these lodges, though I did not understand their significance earlier. These lodges and other beaver activities are nothing short of amazing. Not only are they the animals to most shape their environment besides humans, they are also capable of constructing insulation from mud and sticks. Furthermore, the underwater exits from lodges keep them hidden from predators while allowing their users free-movement, even as ice coats the top of wetlands. These tunnels also lead directly to a “pantry” of sorts: piles of sticks and other foods held underwater for hearty winter eating.

The dams that create their habitat in the first place are also clever in their construction, as beavers fell larger trees with precise aim to serve as a base for smaller harvested branches. This process has the multiple uses of feeding beavers cambium and soft inner wood, creating the environment for their lodges by flooding wetlands and killing trees nearby for the benefit of other species that require dead, standing wood.

The wind blasts through my layers as I approach a trailhead of the TAM. Immediately upon entering, I am struck by the number of fallen trees. Curious as to the cause of this upheaval, I go through possibilities in my head. Given today’s wind, this is the first cause that comes to mind, and it makes sense given the height and breadth of many fallen trees. Another cause could be human activity, an idea supported by the litter and clear-cut path to walk deeper into the forest. My attention is finally grabbed, however, by the deep scars in a Scotch pine (Pinus sylvestris) just off the trail. Upon closer inspection of the rectangular holes, the culprit is revealed to be a pileated woodpecker (Hylatomas pileatus), though no birds can be heard or seen during this windy sunset. These holes differ from the smaller, well organized bores of the sapsucker (Sphyrapicus) that litter surrounding live sugar maples (Acer saccharum), different to the lifeless targets of pileated woodpeckers.

The large-scale impact of pileated woodpeckers is often overlooked, though the process is necessary for many forms of life: by pecking away at dead or sickly tress, they reduce their structural integrity and encourage the process of decay. Additionally, these carved holes and decaying trees provide homes for many species of insects, fungus and lichen. In the body of a fallen white pine (Pinus strobus) on the TAM, for example, a silver cyst-like “puffball” fungus prospered, as well as an expanse of green-blue lichen enjoying the last sunshine of the day. A spider’s web can be seen poking out from under the bark, a competitor of the woodpecker for insects that make their home in the rotting trees.

It is reassuring that despite the lifeless impression one a fallen tree initially conveys, it is actually pulsing with diverse forms of life, as well as creating nursing grounds for future inhabitants of the forest.

It is a relief to see that the ice pillars of Smuggler’s Notch remain despite this winter’s turbulent weather. I feel excitement and anticipation building as worries regarding the ice conditions fade from mind. It is a delicate and persistent process that allows streams and waterfalls to freeze into elegant ice pillars, especially those formed enough for climbing. Indeed, due to the turbulence of moving water, freezing occurs uniformly throughout the entire flow instead of spreading from colder pockets. This means temperatures must drop well below the typical freezing point of water in order to create ice. If temperatures of below 21 degrees can be maintained for sufficient time, the first signs of freezing will occur in the form of frazil ice, minuscule bunches of supercooled water molecules. These thin forms will stick to the frozen rock beneath the flowing water, slowly creeping downward as more molecules are captured in the formation. Eventually, a stalactite of ice will be formed and the waterfall will be frozen in an awe-inspiring likeness of its liquid self.

One of the most fascinating traits of these frozen flows is their inherit variance over time; it is sure that a frozen waterfall will disappear in the spring. Yet, for this dependent change, the wildlife surrounding these flows can expect a deep freeze and thick coating of ice each winter. Nonetheless, moss persists directly on the frozen rock face and an impressive variety of trees, clearly having lasted several winters already due to their size, remain alive despite a frozen coating. This impressive hardiness can be credited to a trees’ ability to prioritize the protection of living cells. Interestingly, despite their role in everyday functions, most cells in a tree are already dead, allowing for a massive tree to focus on protecting a relatively small area. Much like the freezing of the waterfall, it takes much time to prepare living cells to endure winter, and the thermal properties of water are cleverly utilized. One such method to keep living cells unfrozen is to increase the concentration of sugars within cell membranes. This, like turbulence in a river, keeps water liquid below its traditional freezing point. These cells also release water through their semi-permeable membranes when ice begins to spread further, forcing ice to expend thermal energy to cool the new liquid at the same time as increasing the concentration of sugar within their walls, a natural anti-freeze.

Evolutionary adaptations such as this are reminders of the flexibility and diversity of life, and it is always remarkable to go to one’s limit only to find another organism quite at home in the same situation.

Observations made 14 January, 2017 in Smuggler’s Notch, Vermont.