Sunday, December 27, 2009
Trees and Farms: How Forests Support Sustainable Agriculture
Gimme a one! Gimme a two! Gimme a tree! Actually, I’ll take a tree any day. A few would be good, and a whole forest would be even better. Trees aren’t just what grows where there are no farms and no houses. They play a very important role as a support structure for sustainable agriculture. How is it that a tree can act as a steward to the plants that we eat?
Trees preserve the soil. Particularly if they’re native to the area, trees build the soil with their leaves when the leaves fall. Even in a climate that does not contain deciduous trees, leaves still fall on a continuous basis throughout the year, and this provides a consistent inflow of nutrients into the soil.
Trees also preserve the soil with their roots. They keep the soil from washing away during rain. This is especially important when farming takes place on steep slope. Farmers don’t want a huge landslide of mud raining down on the farm. Nor do they want the farm soil to escape further down into a watershed, taking with it the nutrients built up over the years. These nutrients sustain a healthy, vital farm – the soil isn’t just a place to put plants.
Trees also keep the water filtering into the soil and into the groundwater, rather than letting it flow rapidly over the surface of the ground. Those roots and those leaves slow down the water, forcing it to move downwards into the soil. Some of the water stays on the leaves and evaporates again, while other water stays on the leaves and dribbles down through the forest canopy over time, providing a source of moisture for epiphytes and eventually for the soil below.
Traditional agriculturalists have known that trees help sustain farms. Sacred groves of trees on terraces, special groves kept around oases – all of these are signs that people have always known that growing food for people involves more than just a farm, it involves all of the ecological support structures around that farm as well. And of course, in many cultures the forest is the food and the farm. Forest farming is gradually making a comeback in many countries such as the Philippines, as people recognize that the forest has always been a source of food and that preserving the trees and growing food under the forest canopy is a logical step that preserves the forest and agriculture at once.
Is preserving the environment part of preserving farmland? Of course. In many instances, the two work hand in hand, the natural spaces helping to sustain those that are cultivated by humans.