Photo by Fgrammen, Wikipedia Commons
Nature walks can be taken in the woods, across open meadows, or along river or lake or ocean shorelines. You can also take nature walks along suburban streets. Deborah and I took a stroll around a nearby suburban neighborhood to see what the ecosystem was like.
The most prominent features of this neighborhood, as would be true of almost any randomly chosen section of suburbia, were the lawns. Each lot was about 20 to 25% occupied by a house, garage, and driveway leaving the remaining 75 to 80% of the area for grass. Most of the lawns were closely trimmed and densely vegetated with tightly packed grass plants. Fescue and bluegrass were the dominant grasses. Most of the lawns were extremely controlled monocultures (as pictured below): no clover, no dandelions, no ground ivy, and no “weeds” of any kind. Occasionally, we passed a yard that had escaped from this controlled state, and it had abundant dandelions, ground ivy, plantain, and dozens of other low growing green plants filling in the spaces around the still thriving grass plants (picture further down the page … actually that’s a picture of my lawn!).
Photo by D. Sillman
A monoculture of any kind be it lawn or cornfield is an unstable ecosystem. Successional forces and waves of opportunistic, invading species (collectively referred to as “weeds”) exert immense pressures on the system. These forces would very quickly change a lawn- grass ecosystem into a system dominated by annual weeds (and we observed several of these weed patches, mostly tucked away in spaces outside of fence lines, on our walk).
Over time (a growing season or two) these relatively simple annual weed systems would accumulate species and become an increasingly complex, perennial weed ecosystems (we did not observe perennial weed patches on our walk…societal and peer pressures probably prevent this degree of succession from being tolerated in such close living quarters!). Succession would not stop with these weeds, though. The perennial weed system would continue to grow and mature into a shrub patch full of raspberry canes, hawthorns and whole slew of exotic invaders like multiflora rose and barberry. These shrub systems are very common out away from the neighborhoods in much of the surrounding, abandoned farm yards and fields.
Photo by D. Sillman
Eventually, these shrub patches would develop into forests of first fast growing, sun-loving trees (like red maple, or black cherry, or white ash, or yellow poplar (the very trees that dominate the woodlot on the edge of my mowed field)), and, over time, a more complex forest of slower growing but longer lived tree species would develop.
To the grass manager, this successional process must be directly battled in its earliest stages with the familiar tools of modern lawn care: mowers, trimmers, herbicides, irrigation, and fertilizer. The grass manager (i.e. the home owner) sets up a regime in which the grass plants are vigorously stimulated to grow (by the addition of water, fertilizer, lime etc.), and in which less desirable plants (the “weeds”) are selected against by the frequent plant tissue destruction caused by mowing (and the more you “feed” and water a lawn the more you have to mow it!), or by the very occasional direct removal of “weeds,” or by the very frequent, broad application of herbicides designed to kill non-grass plants. These steps are the only way to insure that a lawn remains a singular grass ecosystem.
The cost of this control is astounding. Here are some numbers for lawns in the United States (derived primarily from EPA, Audubon Society, and The Garden Club of America publications and web sites):
1. 54 million people mow their lawns each summer weekend, 800 million gallons of gasoline are used in gas lawn mowers each year,
2. 17 million of these gallons of gasoline are spilled during refueling mishaps,
3. mower exhaust and the volatile organic chemicals from the gas spills contribute to summer ozone production in he lower atmosphere (“smog”) and also generate about 5 % of the nation’s total air pollution,
4. 78 million pounds of herbicides/pesticides/fungicides are used on lawns each year (with almost no oversight or control),
5. 3 million tons of fertilizers are applied to lawns each year (again, with almost no oversight or control),
6. 50 to 70% of the total residential water volume is used for landscaping (mostly to water lawns),
7. a total of $30 billion is spent annually on lawns (installation, care, and maintenance).
8. lawns in the United States cover approximately 50,000 square miles. This area represents the largest single, irrigated “crop” grown in the United States.
There have been some interesting studies on the historical development of lawns and the lawn culture in the United States over the past century. One of my favorites is Virginia Jenkins’ 1994 book, “The Lawn: A History of an American Obsession.” As one reviewer of Jenkins book put it, “in the 18th-century English landscape, a folly was an extravagant building or ruin. In the 20th-century American landscape, the folly has to be the lawn.” Further, “military metaphors used by advertisers and lawn-care experts alike were part of a male viewpoint that saw nature as something to be “controlled and mastered.” It wasn’t long before that a controlled lawn, once a sign of affluence, became the strictly enforced norm of good citizenship and general moral rectitude” (Book review by “Reed Business Information, Inc.,” 1994).
Photo by L. Kalbers
The growing economic and environmental cost of maintaining lawns, especially in regions of low rainfall, have begun to raise serious questions about the future of this phenomenon. Added to these concerns are the realizations that the grass plants themselves that have assumed such a dominating presence in our urban, suburban, and rural landscapes are, in fact, non-native, and, frequently, invasive plant species. Even “Kentucky” bluegrass is a plant native to Europe, Asia, and northern Africa! Above
Photo by L. Kalbers
and to the left is a picture of my friends’, Larry and Ann, original front lawn of their home in Los Angeles. Last year in response to the ongoing drought and also to a reward program sponsored by their water authority they laboriously removed the alien, invasive sod that has grown there for many years (and which had demanded both watering and mowing) and planted in its place a dry plant community that requires neither! The second picture to the left shows their new front yard ecosystem! It is not only aesthetically beautiful, but it is also much more ecologically in tune with the climate of southern California.
I contend that lawns in any climate zone are barren ecosystems. They are empty, energy and resource hungry spaces that support and sustain very little life! To a pollinator a lawn is a desert, to a small mammal or a bird it is a flat expanse of mostly unusable space. Lawns remind me of George Monbiot’s description of stepping out of a relic forest into the moorgrass covered Cambrian Mountains in Wales: the open, tree-less spaces were green deserts created by human activities and were painfully devoid of any life at all (see Monbiot’s “Feral: Rewilding the Land, the Sea, and Human Life”). If you allow yourself to visualize what these ecosystems (either lawns here in Western Pennsylvania or all of those barren mountainsides in Wales) could (or should) be, their current ecological bankruptcy comes very clearly into focus.
(Next week: Part 2 of our walk, trees and animals!)