Based on Mader, Sylvia S. 1996. Biology - 5th ed. WCB and Cox, G.W. 1997. Conservation Biology, 2nd ed. WCB.
Reading: Cox Chapter 6.
This page contains material from the temperate forests unit.
Note: These notes are a skeleton, which your instructor will embellish with anecdotes and illustrations, both verbal and visual during lectures. Therefore, reading these notes is not a substitute for coming to class!!!
These forests form a band south of taiga in northern hemisphere. They grow in areas with a growing season between 140-300 days and with 75-150 cm rain/year. They have a complex understory; some species (particularly small species) flower in spring before canopy leafs out. For animals in a temperate forest, nuts (seeds of the dominant trees) are an important food source. Many of the food chains in the forest, however, are detritus based. Many organisms depend on nutrients and energy released from the leaves which drop to the forest floor each fall (annual leaffall before the cold season is a characteristic of the temperate deciduous forest). While the soil is rich, more of the nutrients are tied up in the trees, to be released when the trees die. You might want to check out some of the animals in the forest such as the flying squirrel and the gray wolf. If you want to see distribution maps for different plants in the forest, try the PLANTS database.
Virgin forests are those uncut by humans; there is little of this left in the eastern United States. It is interesting, however, that areas around Marietta now have more forest than they did at the turn of the century. Before the widespread use of tractors and trucks, horses and oxen provided the power to till the fields and move the crops to market. These animals themselves needed food and pasture, and a substantial amount of land was needed just to support the draft animals. While we often view mechanization as a bad thing from an environmental standpoint, much of southern Ohio (and the eastern US in general) is forested today because we no longer have to maintain huge herds of draft animals. This has allowed (through the process of succession) secondary forests to develop.
Forests are subject to other disturbances besides being cleared for farmland. They are harvested for their wood; divided by highways and power-line right of ways into smaller fragments, subjected to aerial spraying of pesticides to combat outbreaks of pests, exposed to acid deposition and other air pollution, and so on. Sometimes in protecting them we mess things up by preventing fires for long periods. This leads to a buildup of dead wood and leaves that can lead to very extreme fires. The flora and fauna of forests also shifts as succession proceeds, and allowing large areas of land to return to forested conditions may actually reduce the diversity of that land, because it eliminates the species that live in the intermediate successional stages.
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