Reflections on Water - Chapter 4 Dialog
Chris Nicodemus & Katrina Meserve
Q. Why is the winter of 2025 different than our recent milder winters?
A. We are having the kind of classic winter that snow lovers remember best. The pattern of snowy winters shifting to wetter and icier winters with variable extremes of warmth and cold has always been the pattern in northern New England. Furthermore, the patterns often follow multi-year patterns. Snow mobile corridors and Nordic ski areas can shift from feast to famine during these shifts. Water buffers the climate and sea water temperatures, influencing the pattern of steering winds that separate northern and temperate high-pressure domes or ribbons around the planet. In the winter of 2025 moisture is primary shifting from west to east along a flat curve and northern New England has consistently remained under the influence of the northern airmass. The frequent light fluffy snow that sublimates in dry high pressure absorbing energy has resulted in the frequent deeply chilled mornings the North Country valleys have seen in January and February.
Q. What is the dew point and why is it important for gardeners?
A. The amount of moisture that can remain vaporized in air is a function of temperature and pressure. 100 % humidity is the dew point at which moisture will precipitate out of the air as dew, mist or frost. Water therefore serves as a buffer to falling temperature holding temperature steady at the 100% humidity point and only slowly dropping as the total moisture diminishes. If one’s weather station can measure humidity and calculate a dewpoint, one can have a pretty good idea of whether a clear night is likely to bring frost. If the dew point in the evening is calculated to be in the upper 30’s or low forties, the likelihood that the air will dry out enough to freeze delicate plants is low.
Q. Why does Humidity buffer extremes of high temperature?
A. In a damp environment there is liquid water that vaporizes as the temperature rises and the energy used to change liquid water to vapor causes the phase shift before further increasing temperature. Even though the absolute temperature is limited, the air however will feel very hot as further evaporation of liquid water into the humid air is slowed and cooling moisture on one’s skin does not evaporate easily, so one feels damp and hot, and one’s laundry dries slowly.
Q. Is there a good example you can share of a failure to reforest?
A. After settlers deforested New England, soil and moisture conditions allowed for reforestation. That is not however, a foregone conclusion when one clearcuts an environment. A great example of failure to re-forest can be found on the Island of Cres in Croatia. In the Middle Ages as Venice expanded, natural oak stands on the Island of Cres across the Adriatic from Venice were harvested for the placement of piles into the coastal marshes on which the city was built. After the oak was removed, the arid conditions of the region did not favor regrowth of new oak trees, soil eroded, and a rocky arid landscape emerged that persists to the present day. Interestingly there is a central Lake on the Island, visible on a google satellite map surrounded by ridges on all side in the center of the island. The old growth forest located there could not be easily harvested and dragged to the coast, so that forests persist to the present day. In the central valley a cooler dense hardwood forest persists, and the slopes above the lake have retained their soil and a temperate ecosystem persists. It is a fascinating place to visit, to better appreciate how existing forest landscapes modify the local climate to favor a stable environment. While the conditions that allowed the forest to grow in the first place perhaps at the end of the last ice age dominated by glaciers on the nearby Alps to the north have turned dryer, the forest creates a local environment that sustains itself.
The Lakes of Southern Eurasia and the Lakes of Great Basin of North America persist in arid locations that in early times were less arid. Disturbances by man in the flow of rivers, diversions for irrigation as well as trapping and removal of beavers have all contributed to emerging desert landscapes, loss of ground water and depletion of aquifers.
Banner Photo by: EP Chow
