New England Foliage & the Future of our Forests
By: Eileen Willard
When October begins people who hardly noticed trees all summer suddenly start paying lots of attention to the changing colors that signal cold weather is on the way. The nights are longer. A change is taking place. Summer has ended, but now we get to watch a truly spectacular and short lived festive display. Dull green leaves turn the brightest reds, oranges, golds and browns. It is nature’s end of summer party and hopefully you will join it by walking along the trails of the Arundel Conservation Trust.
But there are other changes taking place on a much larger scale and over a longer period of time beyond our predictable 4 seasons. Some forest changes do so over decades, and hundreds, even thousands of years.
Forests in New England have undergone enormous transformations since the retreat of the last glacier that covered New England with a layer of ice a mile thick 20,000 years ago. By 12,000 years ago the tundra-like landscape left behind after the glacier melted began to establish plants and trees in a process called “succession”. One type (species) of plant or tree flourishes for a while and then is replaced by another over time. This can happen with one species or a group of species (a community). Competition for needed resources like nutrients, sunlight and water make patches of land more or less suitable for the next group of plants or species. In Forestry the technical term for these changes over time is called succession. Just as a monarchy in a country determines who will succeed to the throne, succession in forests determine which trees will dominate. As new species continue to move into an area, they in turn change the soil and available light even more and make conditions desirable for future species. It is an ongoing process over a year, or decades and even hundreds of years.
As I walked the Arundel Community trails for the first time this summer I couldn’t help but notice forest succession occurring at a pretty accelerated rate primarily due to logging and removal of trees a a few decades ago. The amount of sunlight now pouring in where tall trees once shaded the forest floor changed growing conditions. I knelt down to count the growth rings on a large hemlock stump beside the trail. Eastern hemlocks cast so much shade on a forest floor that barely any other plants or trees can get enough sunlight to survive. As a consequence the area ( the understory) under hemlocks is often bare looking.
After the logging and tree removal, sunlight flowed in favoring the rapid growth of different native species like red maples, balsam fir, eastern white pine and shrubs. In all directions I saw hundreds of small balsam firs and red maples. Increased light created an opportunity for germinating seeds of all sorts of plants. Most of these seeds had been lying dormant in the soil for years, dropped by neighboring trees each fall but not getting a chance to grow because they needed more sunlight. Covered by a protective hard coat, some of these seeds managed to survive for years in the soil! When conditions changed favorably some of those seeds had a chance to sprout (germinate) and grow into small trees (saplings).
Forests have resiliency. They can bounce back after ice storms, logging, forest fires and hurricanes! But, it won’t look exactly like the old forest before the disturbance. Some of that resiliency is almost immediate with sun loving groundcovers and brambles moving in. Some plants and trees take many decades to establish regrowth.
Not all regrowth bodes well for the Arundel Community trails, however. Changes also create opportunities for invasive species to gain a foothold and outcompete our native species.
I recognized glossy buckthorn, Frangula alnus, sprouting up and growing well on either side of the trail. This shrub grows quickly, spreads rapidly with profuse berry production. It can take over and reduce the abundance of the more desirable native saplings. The Maine Department of Agriculture, Conservation and Forestry designates glossy buckthorn as “severely invasive”. Originally from Northern Africa, Europe and Central Asia buckthorn presents a challenge to the balance of nature this forest enjoyed before its introduction after the logging took place.
What will the landscape look like in the decades to come? Will the diversity of plant and animal species decrease? Can good stewardship make a difference? What is the best course if intervention might help?
Maybe while enjoying the seasonal changes of fall colors this autumn we might also ponder how changes over a longer time frame will shape the Arundel trails and forests of the future.
Author Bio: Eileen Willard taught Dendrology (the study of trees) at UNH as a Lab Instructor for 15 years and is currently becoming a Maine Master Naturalist. She leads Tree Walks for local Conservation and Land Trust Organizations and works part time at the Wells National Estuarine Research Reserve. Volunteering with the Road Rangers of Kennebunk and Wells to keep roadsides cleaned up gives her a chance to ID all sorts of roadside flora and eat blueberries in season!