Understanding and Accelerating Succession
Like natural systems, small farm systems created through Permaculture Landscape Design evolve towards more productive states by succession.
However, in Permaculture we accelerate the normally slow process through clever design, and can gain yields at every stage to support simple living on farms rapidly, rather than waiting several decades for nature to do it for us.
WHAT IS SUCCESSION?
Natural systems evolve slowly to more productive states by succession. The process of succession begins naturally on landscapes denuded or devastated by agents such as fire, drought, flood or lava flow.
Such impoverished landscapes will first be colonized by hardy “pioneer” plants. These species, which include short-lived nitrogen fixing shrubs and many weeds, act as nature’s band-aids.
The role of weeds and other pioneers is to restore conditions favorable to more productive and biodiverse systems.
Because of this they are usually either relatively short-lived perennials (plant life span of just a few years) or annuals (plant life span of less than a year).
ACCELERATING SUCCESSION IN PERMACULTURE LANDSCAPE DESIGN
We can accelerate the attainment of a long-term, stable and productive landscape in our cultivated systems by carefully planning the succession of plants and animals to yield us short, medium and long term yields.
Utilize pioneers that are already there:
Weeds and other pioneers that are not part of your long term plans for the system can be slashed or cultivated into the soil as a green mulch. When done before they set seeds this not only improves soil but also aids weed control by preventing them from reseeding. Because they accumulate needed minerals, some also make great liquid fertilizers.
Pioneers are there because soil conditions are not ideal. Reconditioning your soils will both dissuade weeds and enhance the growth of desirable species.
Plant improved soils to desirable species
Once soil conditions (including reticulation, if necessary) are favorable, you can successfully plant a diverse range of higher yielding species.
Protected from stock and planted into well prepared soils, such complexes will thrive and effectively out-compete weeds by shading and their physical occupation of space.
As they mature, progressively larger stock can be introduced periodically to harvest their fruit and fodder yields and produce meat, feathers, wool and milk.
In Zone 2, mature system plants will include homestead and commercial orchard species, accompanied by their guild species, and intercropped with useful annuals.
In Zone 3 these may be multi-purpose livestock fodder complexes: species guilds of herbs and shrubs centred around trees of oak, mulberry, tagasaste, and honey locust.
In Zone 4 climax plants may include woodlots designed to yield honey, timber, fence posts, firewood, oils, bark and fruit.
Initial plantings (as in natural re-growth forests) will be dense. As the trees mature, the planting is thinned to yield pole timbers. Progress thinnings performed to provide more space for the best trees to mature yield increasingly large and more useful poles and timbers. Many species will survive repeated coppicing (harvesting by cutting close to the ground), and regrow useful timbers. This way they provide a continual supply of yield without the need for replanting.
Stage stock access:
At the establishment phase, all livestock is excluded. However, small livestock such as chickens or guinea fowl can be permitted into the system once herbage is established, provided slower growing climax trees are protected with tree guards. They help productivity via their manure and insect eating.
In the initial few years the system can yield eggs and meat, and annual crops such as inter-planted vegetables and herbs.
After 3 to 5 years the system evolves to a semi-hardy state, allowing periodic grazing by larger stock such as geese (which may strip the bark and foliage from younger trees). I have also seen unfenced young red gum successfully protected from livestock by flank plantings of palatable species such as tagasaste, saltbush and acacia.
An evolved and stable system can be attained after 5 to 15 years. It can grow large foragers such as sheep, goats and pigs, seasonally, and besides forage, produces a variety of marketable yields such as timber, aquatic and animal products.
At its climax, the system now requires little energy input apart from management, and provides its own fertilizer and mulch automatically.
The succession principle can also be applied to aquaculture. When the dam is first built, only plants are introduced. Only once these are established and the system is semi-hardy, does it receive its first fish and shellfish.
Incorporate pioneers in the design:
Many pioneers offer productive yields and are vigorous and hardy under dryland conditions. Tree legumes (e.g. acacia, honey locust, tagasaste) are ideal as nurse trees to protect and nourish climax species such as orchard, nut and woodlot plants.
They are worth planting early in your staged implementation process and will improve soil and microclimate conditions for later plantings.
Many also can function as fire retardant windbreaks and hedgerows that simultaneously provide other valuable yields in the form of high protein livestock fodder, and gap season pollen to maintain hive honey production.