by Charles A.M. Meszoely and Lawrence B. Mish*
Even the casual observer cannot fail to notice the great variety of trees in the Great Woods. Oaks predominate on uplands, beeches on slopes and flatlands, red maples in swamps and white pine and red cedar in old fields. Dense brush covers large areas and many of the swamps and flatlands are jungled with greenbrier tangles. One hundred species of trees and shrubs have been identified in the Great Woods. A few beeches are carved with 70 year-old dates and the oldest trees (mostly beeches) are some 150 years old. Among the less common trees are tupelo, hemlock, yellow birch, flowering dogwood, and mountain laurel.
The variety of trees and shrubs is caused by differences in soil types, terrain, surface water and exposure. Time and man are also involved. As cleared fields are abandoned they follow predictable stages in their return to forest. Each of these stages can be found somewhere in the Great Woods.
In much of the Great Woods, the first stage of the return to forest began soon after the farmers left for better paying jobs in factories and mills toward the latter half of the 19th century. Red cedars and various woody shrubs staked claims in the middle of the abandoned fields, while birch, oak, maple and pine slowly invaded from the edges. During the second or intermediate stage a mixture of faster growing evergreens and smaller deciduous trees developed. The final stage appeared as the oaks, beeches and maples grew larger, and forced out many of the evergreens and shrubs. Much of the woods is at present still in the intermediate stage, the transition having slowed because of the extensive lumbering and charcoal operations of the early 20th century.
The wide variety of plant communities in the Great Woods increases the variety of birds and mammals. Pheasant, meadowlarks, woodchucks and field mice prefer open spaces. Red squirrels are found in the pine stands, and gray squirrels, deer and grouse are attracted by the acorns of the oaks. The stone walls are a haven for small rodents such as white-footed mice and chipmunks and the blue jay seems to be everywhere.
Abundance is as important as variety. All animals regardless of their eating habits depend ultimately upon plants for food. The fox may eat a gray squirrel which gathered energy from acorns. As energy moves up the food chain from plants (producers) to herbivores (primary consumers) to carnivores (secondary consumers), losses occur. For example, only 10 per cent of the vegetation eaten by a rabbit becomes rabbit. Thus a great deal of plant material is required to maintain animal populations.
Many animals are also dependent upon plants for shelter. They build nests in branches, live in the holes of trees and find refuge under low hanging limbs.
There are values to man as well as to wildlife in the vegetation of the Great Woods. One full-grown tree has the cooling effect of several air conditioners. It is no coincidence that the summer air in Mansfield and Norton is several degrees cooler than in Boston. The cooling involves the conversion and recycling of liquid water to water vapor, much as perspiring cools human beings on a smaller scale. Besides cooling the air, trees clean the air of many air pollutants. Trees also help control noise pollution by muffling the sound produced by cars and industry.
Green acreages, such as the Great Woods, are a valuable asset in combating pollutions caused by our industrial, automobile-oriented society. The less the disturbance of the Great Woods, the greater the health and well-being of the people who live around it and the animals and plants that live in it.
*Charles A.M. Meszoely, Ph.D., is an Associate Professor of Biology at Northeastern University. He teaches a course on Environment and Man and is a Mansfield resident.
Lawrence B. Mish, Ph.D., is a Professor of Biology at Bridgewater State College