2.3.12. Use the Edge and Value the Marginal

“The edge of things is where the energy happens.” We’ve all heard terms like “edgy” or “cutting edge” or “pushing the envelope.” 

In nature, edges are called ecotones. This is where one ecosystem meets another. An example would be a woodland stream - the edge would be where woodland creatures and plants, stream creatures and plants, and creatures and plants unique to the edge ecology would all gather. It could have 3X the diversity of the stream or woodland ecology. A meadow/woodland edge is another opportunity for increased production and diversity. Often fruit is found growing at the water’s edge or at the edge of a clearing. 

One of the most permanent forms of agriculture in the world is swidden or milpa agriculture practiced by Mayan and other indigenous people. A clearing is created through slash and burn, staple crops such as corn, beans and squash are planted for a couple of years, and then the clearing is planted with what essentially becomes a food forest and another area is cleared for staple annual crops.

Now they have a food forest in their original clearing, and lots of carbohydrates via their corn fields. Over time, this may be done over 15-20 different spots, returning to the original spot once in a generation (see the Further Study section for a more in depth coverage of swidden agriculture). 

So how is this useful to us as designers? We can recognize edges as opportunities to increase yield. Leaving a meadow rather than filling it in with trees offers more potential pollinator wildflowers, some protection from trees yet plenty of sun for frost sensitive trees planted on the edge of a wooded area, a diversity of plants for animals to graze, etc. 

There can be edges in time as well as space. The edge between a mature food forest and a young one is a great opportunity to grow annual staple crops or short term perennials in between the young trees, for instance. 

The edge of a garden bed could be framed up with wood or another material, or allowed to taper down, creating an opportunity to add more plants to the tapered edge. The edge of a wet area of the yard, rather than being filled in and made level with the rest of the yard, could be the perfect place for thirsty plants like bananas. 

This principle runs deep and there are many potential applications. We’ll cover more later in the course.