A Blanket of Snow

It is December in northern Illinois, and that means the cold grip of winter is upon us.  With the change in temperature comes a certain change in precipitation.  Snow is here.  When Ryerson Woods conservation area is blanketed with a fresh snow, it is one of the most peaceful experiences.  Snow has a great impact on forest systems, and is a necessity to the natural cycle of the seasons.
Having a snow pack on the forest floor does assist in maintaining the health of an area.  Most importantly, it affects the soil.  The layer of snow acts as a blanket, keeping the soil insulated.  This insulation prevents the soil from actually freezing.   Warmer soil keeps root systems healthy and vibrant throughout the winter.  When snow is present, fine roots are able to stay healthy and maintain their productivity.  If snow is not present, these roots often die due to intense cold.  When roots are disrupted in the winter, they have an increased loss of carbon and nitrogen.
When there is no snow pack, the frozen soil cannot hold carbon.  This is a looming issue, as the eastern forest of North America absorb roughly 15 percent of the total carbon in the world.  If they continue to loss snow pack, the forests ability to be a carbon sink may be tested.  This is one of the main concerns of a global temperature change.  If our snow pack is continually lower than what it once was, we will lose large amounts of carbon to the air.  When snow melts in the warmer months, it is necessary water for the soil.   If we do not have snow, it can easily put forests into drought conditions before the growing season, slowing productivity.
Snow also plays a large role in the shaping of the forest canopy   Heavy snow and winds during winter storms affect the branch systems of many trees.  Dead branches, as well as some live ones, will inevitably break from this sitting snow.  The snow opens the canopy, and allows in more light.  This will regenerate certain tree growth.  By increasing the amount of light to the forest floor, these gaps in the canopy assist the overall productivity of the forest.
A snowy winter also affects the fauna within a forest.  When temperatures drop and ice freezes over most small lakes and rivers, it can be very difficult for animals to find drinking water.  Snow is an integral fix to this situation.  Many birds, such as Black-capped Chickadees, actually eat snow to gain water necessary for survival.  Also, snow acts as great cover for many smaller mammals.  If you walk in a fresh snow, you may see tubes burrowed into the snow.  Mice and voles often create intricate networks for tunnels throughout the snow, even making nests.  The snow gives protection from top predators, and also provides the small mammals with insulation.
Finally, snow is a great addition to the woods for anyone wanted to experience winter.  It is aesthetically pleasing and can be used for recreation.  Many people use the ski trails at Ryerson woods.  Cross-country skiing is a great way to get exercise and see lots of forest quickly.  Snowshoes are also a great way to play in the snow, but they usually require a very deep snow pack to be effective.  Visit Brushwood Center's website for upcoming programs, such as Introduction to Snowshoeing (January 25, 2014) and Introduction to Cross-country Skiing (February 1, 2014).
Although it may make driving a hassle, snow in the wintertime is a wonderful thing that should welcomed.  The forest in northern Illinois have adapted for annual snow, and hopefully it will be present all winter, creating a more healthy forest.
This blog post was written by Luke Buckardt, who assists Brushwood Center with social media.  Luke graduated from Northland College in 2012 with a degree in biology.  He grew up in Riverwoods and has roamed Ryerson Woods since he was young, knowing the preserve intimately.