Conifers add green to our winter woods
Winter solstice, the first day of winter, happened this week on Dec. 21. The meteorological winter began as we entered this month of December. But those of us who are observers of Northland nature happenings know that the seasons do not begin or end on a particular day. The changes progress gradually. Anyone who spent the last few years here remembers how the winter began in 2013 as compared to the reluctant start of 2015.
However, it does look like winter in 2016 has arrived. In addition to the calendar notifications, I recorded some other weather happenings that we associate with the initiation of the cold season. Along with snow that remains on frozen ground and temperatures that reached subzero starting on Dec. 10 — something that did not happen last year until January — we also have plenty of ice. I saw a nearby lake with nearly complete open water on Dec. 7. It was mostly frozen by Dec. 8, completely ice-covered on Dec. 9 and walkable on Dec. 13.
But the real sign that I use for winter’s return is when the ice cover extends onto the rivers and streams. And yes, I observed this happening to many in the region Dec. 10-13. Winter began a few days before the solstice. The cold came on a bit quickly and after a near-record warm November, we may be experiencing a December more normal, maybe even a bit below the usual.
We were not the only ones influenced by this chilly onset. Birds that came to the feeders during the early weeks of autumn now had companions. The blue jays, black-capped chickadees, white-breasted and red-breasted nuthatches, and three kinds of woodpeckers, downy, hairy and red-bellied, were now sharing seeds with newly arrived goldfinches that escalated into a flock of about 50 and a smaller group of purple finches. On Dec. 13, a lone redpoll showed up. It did not last long, but I was glad to see it and hope for a return.
Besides the birds coming to the feeders, I saw a difference in the tracks of critters in the woods. During my walks here earlier, I noted about a dozen kinds of tracks. After the subzero nights, this number was about half, telling me that many were waiting out the cold. But as I walked, I could see that others in the forest were ready for the cold: the trees.
Living here in the Northland, we have woods composed of both deciduous and coniferous (conifer) trees. Both successfully deal with winter, but in different ways. Back in October, most of the deciduous trees dropped their food-making organs (known as leaves) after quite a colorful exit.
Disposing of something as valuable as these photosynthetic leaves does not appear to be a good plan. The green leaves made food for the plants all summer, but besides producing food, the leaves also absorbed and lost much water, a process known as transpiration. This is no problem in the warm times of the year but during winter, the cold air is very dry. If trees kept their leaves, too much moisture would be lost and they would succumb to desiccation. Better to drop the leaves. Besides this dehydration, if trees hold leaves, greater surface area on branches would allow snow to build up and under this weight, branches would break. Again, it is better to drop all the leaves.
The nearby conifers go at winter in another way. With the exception of tamarack which dropped all of its needles in fall, they hang onto their leaves (needles) throughout the winter. Conifers must deal with the same drying and snow cover conditions as do the deciduous trees, but by having leaves that are thin and different shaped, they can cope with cold and arid winter. The Northland is home to about a dozen kinds of conifers, so-called because they form their seeds inside cones. Since conifers are green in winter, they are often referred to as evergreens. We have three native pines (red, white and jack), white and black spruces, balsam, cedar, junipers, yew, tamarack and maybe a few hemlocks.
Most have thin needles that have much less surface area than do the broad flat leaves of deciduous trees. They lose much less moisture in winter and hold the snow cover differently. Looking at our winter scene now, we see their greens and realize how common the conifer variety is in our woods.
Maybe it is the green of these trees that make us appreciate them at holiday time. I find the shape and hardiness of spruces seem to fit this idea the best. White spruce in the uplands and black spruce in the swamps tend to stand in the “Christmas-tree” shape at this time. Snow coats the branches that bend under the weight and do not break. Snow-laden spruces make for picturesque winter woodland scenes for us, but also great hiding places for small mammals and birds.
As we get deeper into winter, these spruces will be ever more needed and used by local wildlife. Whether we use them for shelter or just like to look at them, the spruces and other conifers add much to our winter.