By Susan Johnson
This series of articles will address the different benefits and drawbacks of two types of ecosystems, trees and prairies. Several questions will be pertinent to this topic. These are questions that not many people have asked about the environment.
Q: Which produces more oxygen — an acre of trees or an acre of prairie?
As reported in an editorial by The Rock River Times’ Editor & Publisher Frank Schier, the website About.com states: “A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year and release enough oxygen back into the atmosphere to support 2 human beings.” — Mike McAliney, “Arguments for Land Conservation: Documentation and Information Sources for Land Resources Protection, Trust for Public Land,” Sacramento, California, December 1993.
“One acre of trees annually consumes the amount of carbon dioxide equivalent to that produced by driving an average car for 26,000 miles. That same acre of trees also produces enough oxygen for 18 people to breathe for a year.” — The New York Times
“A 100-foot tree, 18 inches in diameter at its base, produces 6,000 pounds of oxygen.” — Northwest Territories Forest Management
“On average, one tree produces nearly 260 pounds of oxygen each year. Two mature trees can provide enough oxygen for a family of four.” — Environment Canada, Canada’s national environmental agency
Many of the plants found in prairies are species of grasses. Like all plants, grass consumes carbon dioxide, breaking it down into carbon and oxygen. The carbon is used by the grass plant to build for growth. The oxygen is released into the environment. Estimates of the magnitude of this process vary.
The most common estimate [Care for the Environment; How the Environment Benefits; Turfgrass Statistics; Lawn and Sports] says that a 50-foot-by-50-foot square of healthy turf supplies enough oxygen for a family of four. Another estimate, however, claims that it takes 6,000-9,000 square feet of lawn maintained at a 2-inch height to produce enough oxygen for one person [Healthy Turf: Healthy Earth].
Q: Is prairie or forest a better habitat for animals? Particularly pine forest and oak forest? What kinds of animals live in each?
Animals that typically inhabit a prairie range from invertebrates (like grasshoppers and beetles) to large mammals (like antelopes and bison). North American prairie wildlife includes: American toad, ants, badger, bison, black-footed ferret, black-tailed jack rabbit bumble bee, burrowing owl, carrion beetle, common snipe, coyote, deer, dragonfly, eagle, earthworms, Eastern cottontail, elk, ferruginous hawk, fox snake, golden owl, gopher snake, grasshopper, gray wolf, ground squirrel, killdeer, lady beetle, lark, long-billed curlew, meadow vole, mole, Monarch butterfly, Northern grasshopper mouse, prairie chicken, prairie dog, prairie rattlesnake, prairie skink, pronghorn antelope, red fox, red-tailed hawk, shrew, skunk, stink bug, tiger beetle, Western meadowlark, Western tiger swallowtail, white-tailed jack rabbit.
Animals of the pine forests include: American black bear, ants, bats, beetles, brown bear, bushshrike, buzzard, cardinal, caribou, centipede, chipmunk, coati, cougar, crane, crane fly, crow, cuckoo, deer, deer mouse, dormouse, eagle, elk, finch, fisher, flea, fly, frog, grouse, hawk, ladybug, mouse, newt, owl, rabbit, raccoon, squirrel, thrush, tit, vole, vulture, warbler wasp, waxwing, weasel, wolf, woodpecker, worms, wren, yellow jacket. According to the National Wildlife Federation, the longleaf forests in the South are home to quail, turkeys, deer, songbirds and gopher tortoises.
Acorns of the Midwestern oak savannas are a major food source, called “mast,” that varies year by year. In Minnesota, bur oaks seem to be on a two-year cycle, while white oak and Northern red oak species are on a three-year cycle. Sometimes the cycles come together, and all oak species show high masting in the same year. Animals whose reproductive cycles depend on mast include squirrels, bears, and deer. Oak mast is also heavily used by wild turkeys, ruffed grouse, bobwhite quail, raccoons and small rodents. Deer compete with a wide variety of animals for acorns, including squirrels, chipmunks, woodrats, mice, ducks, woodpeckers, bluejays and wild turkeys.
Some animals are common in both habitats, but in either case, how well they thrive depends on environmental conditions caused by nature (such as fire, water supply, snowfall, etc.) or manmade intervention in the habitat. Predator numbers are dependent on the availability of prey species, which may go through cycles of scarcity and plenty.
To be continued …
From the Nov. 19-25, 2014, issue