The Vital Role of Grass

Here is another example of the cooperation between plants, to go along with that explained in "Plants And Light".

Grass has a vital, and very under-appreciated, role in optimizing conditions for other plants. Like humans and animals, plants are complex enough to have a temperature, or fairly narrow range of temperatures, at which they operate best. The most important part of the plant is the roots, which absorb nutrients and water from the ground. There must be an ideal temperature at which this is accomplished with peak efficiency.

Grass is like a blanket in that it moderates the soil temperature by holding onto a layer of air. This keeps the roots of larger plants at a fairly constant temperature throughout the 24-hour daily cycle of day and night. Grass acts in the same way as hair or fur in that it shades to restrain sudden heating upon sunrise, and insulates by holding onto a layer of air to prevent quick cooling after sunset.

Notice in areas of desert how quickly heat is gained early in the day, and how quickly the heat is lost at night. These extreme daily temperature changes would be destructive to the operation of most plants, and grass serves an essential role in moderating this.

Smaller plants, with roots that do not go as deep, would obviously be the most affected by daily temperature swings. But even trees, with much deeper roots, are assisted by the long grass which usually sorrounds them.

These plants, in turn, help the grass to grow around them by providing shade. Unlike larger plants, grass tends to grow better in the shade because it hinders the evaporation of the water that it needs.

But what about the grass itself? My belief is that the advantage that grass has is it's biological simplicity. Obviously, grass requires water just like other plants and that water must be available just below the surface of the soil. But it's simplicity makes it inherently less vulnerable to swings of temperature than it would be if it's operation was more complex. Thus, grass is suitable to cooperate with other plants by moderating the soil temperature for them.