In total, I have six principles I look for in an ecosystem design that puts sustainability front and center. Today, I want to discuss three of them: site suitability, ecosystem form and ecosystem function. And stay tuned for a future post that round out the top six with my final two ecosystem design principles.
Site-Suitability for the Environment
All ecosystems have plants that are suitable to the environment: i.e. the soil texture (sand, silt or clay), the moisture (dry or wet) and the climate (how cold is in the winter or hot in summer). There are many more life forms in a square mile of tropical rainforest than a square mile of a boreal forest. And each environment has plants that are site-suitable, meaning they can survive and thrive in that area in which they are found.
As gardeners and property owners, it is part of our role as stewards of our landscape to continuously discover which edible and useful plants are suitable to our soil and micro-climates. At the Ecosystem Solution Institute, we are trialling 1000s of edible plants to find those suitable to different climates. At home you can also trial different fruits, berries and herbs and see which do best, then drop the rest.
An ecosystem would never continue to grow something that doesn’t perform well but also wouldn’t settle on only growing a few crops and nothing else. For any micro-landscape (5 feet by 5 feet or larger) in your property you can analyze the soil (clay, sandy or loam), sun exposure (full, partial-shade or shady) and understand the hardiness zone (your coldest average winter temperatures) to find varieties that will thrive.
In all ecosystems you see that life has different forms. We often refer to the form of plant canopies and relative size, the distinct shapes of linear or broadleaf plants and the obvious layering and vertical stacking of their canopies.
For instance, in a mature forest you see larger trees, medium trees, shrubs, bushes, herbs, ground covers and vines. Even in a grassland ecosystem, there is similar layering, although the plants don’t grow as tall. For instance, the native prairie grasslands that used to stretch across North America as the infamous home of the bison had many different grasses, forbes, herbs and flowering plants that occupied different layers from 6 to 7 feet above the ground to only 3 to 6 inches off the soil.
In our yards we can design food forests with layered diversity too! Fruit trees can reach up high, shade-tolerant berries can grow underneath, and herbs and ground covers can abound still farther down. This design maximizes the photosynthesis per square foot of a garden or yard.
In other words, more of the sunlight that enters the footprint of your yard will be taken up by plants and transformed into useful fruit, berries and herbs. You’ll also build new soil organic matter, habitat for pollinator species and nitrogen fixed by legumes.
Consider, as an example, a edible hedge planted along any laneway, property front, or fence line. This design could include layered plants that serve many different functions.
All wild ecosystems have plants and animals that serve different functions, result in companionship between plants that benefits the ecosystem as a whole. Sometimes these “services” take the form of symbiosis, or actual evolved relationships between organisms. An example would be mycorrhizal fungi and many trees, where the trees provide sugars from photosynthesis to the fungi, and the fungi supply water and nutrients more easily to the tree through the roots.
Other times, the relationships are more coincidental companionship. For instance, a berry bush can protect a young fruit tree’s bark from sunscald in the winter. Although this is beneficial for the fruit tree, the berry bush never evolved this specific function. It just happens.
In a similar fashion, having taller trees, shrubs and creeping ground covers help prevent erosion of soil for the whole garden ecosystem. When rain falls, it first hits the higher canopy and then trickles down to the forest floor below. There, ground covers further protect the soil and hold it against erosion! In this case all the living plants are helping retain soil to all of their benefit.
Stay tuned next month, when I cover the final two principles of sustainable ecosystem design!