I don’t think anybody who participated in this walk will ever look at a forest in the same way again. Dave Wilson, a certified forester, who was our guide at Clear Springs Nature Preserve, encouraged us to ask questions as we walked, such as: Why is the forest like this right here? Why is this tree or plant here? He told us there are many factors that determine what a forest will be like: soil, light, insects, wind, disease, natural distribution (what takes seed), and human distribution (what is planted). One factor we can control is light. Dave directed us to look at the plants in the forest – he said that tells what the soil is like. Different soils means different plants.
Clear Springs Nature Preserve was a perfect place to explore due to its unique history. In the 1930s, the area was planted with straight rows of red pine by the Civilian Conservation Corps, the CCC. This was during the Great Depression and a way to provide jobs for people, but also to address issues, such as in this case – serious erosion of top soil from farming. Not only do red pines tolerate very dry soils, their needles and other organic materials from the trees, once on the ground, help to hold nutrients in. The major CCC project in Michigan was tree planting – to build the soil back.
Dave explained why the tall straight red pine trees had no branches. He told us that red pines need full sunlight and as the tree canopy closes and reduces sunlight, the lower branches die. White pine like partial shade – they grow well beneath other trees, not full sunlight. Any straight tall white pines we see must have grown up in partial shade.
Dave talked about the positive and negative aspects of logging, remarking that it was certainly shortsighted and irresponsible in the mid-1800s to the early 1900s. The Michigan forest was decimated, and the debris left behind, or “slash,” as it was called, contributed to wildfires across the state. Fortunately that was not the end of the story as the natural process of succession began after all this disturbance. Because enough light was available after logging, oak trees, which require full sunlight, began to grow. Currently red pine is dominant in this section of Clear Springs, but there are oaks and cherry trees waiting for their chance – they have the ability to wait. In about 50 years, the red pine will be gone. The full cycle will bring about a white pine forest in the next hundred years.
Most logging today is vastly different, according to Dave. It can be a positive impact on the forest, for example, removing trees in a mature hardwood forest stand to give space to desired trees. Clearcutting aspen provides good habitat for wildlife as new trees grow in the next year. There is bad logging – when the only goal is for the maximum economic return. Dave says that logging has a negative image with people because we have strong emotional connections to trees. One of our attendees, promptly demonstrated this!
Dave talked about a variety of different trees. He told us that hemlocks were conifers, not pines. They have needle-like leaves, with two white lines under the needle. They are shade tolerant and used often in landscaping. Apparently deer love them! He had us listen for aspen trees in the preserve – they have flat petioles, so when the wind blows, the leaves rustle. Dave noted an area of red pine mortality – and said there is usually a progression of forces that will weaken a forest, allowing something to kill it. He talked about ash and the emerald ash borer and noted that most ash trees they will likely be gone in the next decade. He also mentioned the loss of chestnut, and American elm trees, and noted another disease underway – oak wilt – which plugs up a tree’s vascular system, so nutrients and water can’t travel up the tree and it wilts. Fortunately this disease is not as aggressive as others and although it is a serious threat to oak trees, it is unlikely to eliminate the oak forests of Michigan.
I happened to be in a forested area about a week after our walk. I usually just walk my dogs and enjoy being outside, but this time I really looked around at the trees and wondered what the area had looked like years ago and what influences there had been on this particular plot of land. Next time out, I will be wondering again and looking more closely. Forests are fascinating!
Thank you, Dave, for your help with this blog!