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BAckyard Birder

‘The world runs on grass’

I’ve been thinking about grass for a number of reasons. My favorite, little bluestem, is visible along roadsides now. The “blue” in its name is misleading as it turns red in mid-summer when fuzzy white flowers appear along its delicately branched stems.

A major component of the prairie grasslands, back when there were prairie grasslands, little bluestem retreated to New England’s marginal soils where it colonizes roadsides and old fields.

Grass performs an essential ecological role that doesn’t receive much appreciation. That’s what started this article — a desire to give credit where it’s due — but research on grass turned up a whole lot more.

First the ecological role.

Create bare soil through bulldozer, plow, fire, flood or logging, and grasses are among the first plants to take advantage of sun and room to grow. Seemingly overnight, dormant seeds waiting the right conditions sprout and up come the grasses.

As up to 90 percent of a grass plant is its root system, quick-growing grasses spread their roots and stabilize the soil against runoff and the resulting loss of precious topsoil. Soils washed downhill enter waterways to create additional problems. Besides loss of valuable soils, water quality declines through sedimentation.

It’s pretty simple, but the ramifications for healthy soil and waterways are huge. The unsung grasses perform a key ecological role.

Better known is their role in feeding the world, humans and most other animals as well.

The grass family is a large one. Shared characteristics include a hollow stem with joints, leaves with parallel veins, and minimal flowers. The flowers ripen into a fruit — otherwise known as a grain including wheat, corn, rice, barley, sorghum, oats, millet and rye.

The world runs on grass. Eat a hamburger, one account that I read said, and you’re eating grass, a lot of grass, usually of the corn variety.

Europeans heading west crossed a sea of grass. First they encountered the tall-grass prairie with grasses taller than they were, nurtured by rich, black soil that resulted from centuries of decomposing grasses.

The tall-grass prairie was converted to today’s corn belt, along with factories and housing and shopping malls.

Farther west came the mixed-grass prairie, less fertile because of drier, windier conditions. Little bluestem was a dominant species and forage grass in the mixed-grass prairie.

With settlement, that region was converted to the wheat belt, and little bluestem migrated this way. Grasses have evolved to migrate well.

Farther west came the short-grass prairie, also known as the Great Plains. Drier and hotter, with sparser grasses, this was grazing land — first for buffalo and then for cattle. In time, it became overgrazed. Soil compaction inhibits root growth and rain penetration. Plants such as mesquite and sagebrush that are unpalatable to grazing animals have taken over most of the short-grass prairie.

Traveling in Nebraska years ago, Carl and I tried to find some remnant prairie grasslands. We found a very sad remnant, an attempt at restoration, not the real thing.

Under most conditions, grasses are resilient. An extensive root system stores energy and moisture that helps them withstand repeated mowing, grazing, fire and drought. Growth tissue is located at the base of each stem, not at the tip, and repeating cropping doesn’t inhibit growth or kill the plant.

We mow our lawns and hayfields, and the grass keeps growing.

Many grasses can self-fertilize, so if one seed germinates on disturbed soil, there’s a chance for reproduction and spread. And as any gardener knows, grasses send shoots out laterally. Some species like witch or quack grass send their shoots throughout our gardens with impressive energy.

Beyond the cereal grains in the grass family, sugar cane is a grass refined to produce sugar, and bamboo grasses are used for just about every application imaginable from food (bamboo shoots) to paper to construction materials. And, of course, grain alcohol is the source of many “spirits.”

Returning to the ecological role of grasses, over the eons nature has figured a lot out. Presented with major soil disturbance through glacier scouring or less extreme disturbance such as fire, flood or plow, an orderly, predictable progression that sustains life on earth unfolds.

In New England, the natural vegetation is forest, but there are many steps needed to get there after soil is laid bare by disturbance. Grasses dominate the first colonizers, stabilizing the soil and adding nutrients as decay is part of their annual growth cycle. Shrubs come next and then a young forest of sun-seeking tree species. If given enough time, as well as a lack of the many possible disturbances, what’s called the “climax forest” is achieved — mighty oaks and mighty pines are among the mix in our region.

Each stage of succession supports a different mix of plants and animals ranging on up to the fully achieved, diverse mix found in a climax forest.

Grass doesn’t grow in the final stages, shaded out long before, but grass seeds in the fertile soil await the next disturbance that will bring the conditions just right for seeds to sprout and roots to spread.

Backyard Birder by Francie Von Mertens appears every other week in the Monadnock Ledger-Transcript.

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