In a neat botanical trick, two types of plants make food available for all the other plants. When combined with recycled woodland waste such as leaf fall, herbaceous die-back, rotting creatures and droppings, the soil becomes a nutrient superstore. Ecologically, modelling agriculture on woodland makes a lot of sense. Temperate woodland is a self- regulating, perpetual, abundant and stable ecosystem which supports a wide variety of flora and fauna. The sheltered environment inside the woodland reduces temperature fluctuations, wind and frost, so plants grow more easily.
Trees also lessen the force of the rain on the soil.
Water falling on a woodland floor rich with organic matter is absorbed into the soil and not lost as run-off. Compare this to conditions in a ploughed field. Here, where the soil is exposed to rain and wind erosion, nitrogen and other water soluble nutrients are washed away. In a field of wheat all the plants have the same nutritional requirements, their roots occupy the same levels in the soil and will only be able to obtain nutrients from this one level. In a perennial system some plants will have deep-root systems and these will get many nutrients from deep down in the soil in areas beyond the reach of other plants.