SUCCESSIONAL AGROFORESTRY: PRINCIPLES FOR IMPLEMENTATION AND MANAGEMENT

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We consider the forest to be an organism, and we believe that production systems can only be sustainable if they mimic nature’s logic, also behaving as whole organisms. Nature indicates that it is better to coexist from the standpoint of cooperation, than that of competition. The system evolves to optimize life processes and not maximize some at the expense of others.

The article that follows was written by  Fabiana Penereiro, an agronomist and successional agroforestry researcher member of the Mutirão Agroflorestal (Agroforestry Working Bees). Fabiana has led research and education projects in the Amazon region and many other Brazilian states. In Brasília, where she resides, Fabiana runs a very successful CSA and lately have integrated the Mutirão Agroflorestal (Agroforestry Working Bees) team to help write and implement (in a participatory approach) agroforestry systems that address at the same time the Landless Movement families’ food security and economic issues and the restoration of the Descoberto watershed near Brasília. Their project received funds from a program called Água Brasil, a partnership between WWF and Banco do Brasil launched to support initiatives designed to conserve hydrologic resources in Brazil.

Text by: Fabiana Mongeli Peneireiro
Illustrations by: Darci Seles
Revised by: Mutirão Agroflorestal in November, 2007
English version organised and translated by Eurico Vinna, PhD, and Dr. Doone Wyborn, in 2018

In a rather synthetic and simplified way, I present here the principles that underpin the successional agroforestry. I do not pretend to indicate here revenues to implement agroforestry, even though they do not exist. For each place, there will be a combination of species and for each context / situation a way of handling. The principles are the same, but replication of finished and standardized models is not recommended. I am certain that this knowledge is still under construction and that our best teacher is nature itself.

Besides promoting a rich exchange of experiences, from the perspective of learning more about successional agroforestry, practicing observation and exercising the perception and sensitivity to understand nature’s processes in a collective way, [this body of knowledge] began [to be built] in 1996 by Mutirão Agroflorestal (Agroforestry Working Bees) an itinerant, autonomous and spontaneous movement of implementation and management of agroforestry systems geared to learn and experiment with these system. Currently a group originating from this movement, constituted an NGO of the same name, and through it conducts work for training, consultancy and dissemination of agroforestry.

I believe that agroforestry is situated in a very broad context, covering environmental, socio-cultural, economic and philosophical aspects. It is a new attitude regarding nature, within a new socioeconomic order, where the most egalitarian social relations between men and women, the solidarity economy, the agrarian reform and the community organisation are as important as the technical knowledge. For the purpose of this text, however, I will focus, especially, in the technical issues that influence and should be considered in the implementation and management of agroforestry.

The concept of agroforestry

We can identify basically two lines of thought that guide the work with Agroforestry Systems (SAFs): the one with the assumption of the competition among the species, is based on causality; the other asserts that cooperation prevails over competition, departs from the principle that we are part of an intelligent system, that nature has a purpose and life tends to complexification, as authors such as Maturana and Varela argue.

There are different understandings about agroforestry or agroforestry systems. There are SAFs elaborated as consortiums characterised as combinations of species, seeking to better harness the space and resources (light, water, nutrients); and there are SAFs who seek to reproduce the logic of building a productive forest based on ecological succession.

In the perspective of restoration of ecosystems, the successional agroforestry systems constitute an important strategy, because in addition to helping to recover the soil and to restore the complex ecological relations, they also promote the production of food and other raw materials. In order to promote the restoration of environments and ecosystems, it is essential to carry out the management by supporting agroecological principles, such as natural succession, which presupposes the biodiversity and nutrient cycling (through permanent soil cover), always acting in order to increase the quantity and quality of consolidated life, both in the place of our intervention, as on Planet Earth as a whole (Götsch, 1995).

Foundations of Successional Agroforestry

Let us talk about successional agroforestry here, assuming that planet Earth is extremely efficient in complexifying solar energy through life, and that we are large animals, and we are part of an intelligent system (and not the most intelligent ones in the system.) As part of the system, we have a clear function, that which is commonly performed by large animals, which is to enable the dynamisation of life processes, seed dispersion and the cycling organic matter and energy.

It is with this approach that Ernst Götsch, a Swiss farmer-researcher, living in Brazil for nearly 30 years, dedicates himself to the study and practice of successional agroforestry. He has been developing agroforestry projects, creating real “forest gardens”, producing food and other raw materials, without using chemical fertilizers or pesticides, proving that it is possible for humans to coexist with nature, leaving more life in each place as a result of their actions. The principles and concepts covered in this paper are based on the practical experience and theories developed by Ernst Götsch, through observation and the experimentation carried out over these years, which allowed a great accumulation of knowledge about the subject.

We consider the forest to be an organism, and we believe that production systems can only be sustainable if they mimic nature’s logic, also behaving as whole organisms. Nature indicates that it is better to coexist from the standpoint of cooperation, than that of competition. The system evolves to optimize life processes and not maximize some at the expense of others.

If nature has created forests in the Atlantic Forest region, it is important to understand why; to understand biodiversity’s strategy, the different strata, the dynamics of natural succession and the cycling of nutrients… If we do not consider these, we will always have to use chemical or even organic fertilizers and pesticides as “crutches”, which leads us to dependence on inputs and to the degradation of soil and water, and to bring about the destruction of the rich naturally existing biodiversity.

Sustainability assumes a positive energy balance, that is, we must always generate more life in the place where we are and not the other way around. So, if we seek to achieve sustainability, we must answer the question that Ernst Götsch always reminds us to ask: “Has the result of my actions been the increase of life and resources at the site of my intervention and also in relation to the planet in general?”.

In order to be able to positively answer that question, we need to understand how the natural ecosystem of the place works, and need to apply the principles that govern this ecosystem in our production system. Thus, we need to understand what is the Atlantic Forest’s dynamics, and which mechanisms it uses to perpetuate itself.

Natural Succession

A forest area is not a static environment, it is an area in constant transformation. We know, that in a mature forest, from time to time, an old tree falls and opens a clearing, where different species from those that were in that place so far will establish themselves. This happens because each species has its own characteristics and functions, very different from one another. In this clearing, the first plants that will emerge are the fast-growing ones that like plenty of sun, which are called pioneers. They prepare the place so that other plants, which have other needs, such as those that need a little shade to develop, can establish themselves. Each plant has a function and they succeed one “creating” the other until the forest becomes mature again. This process is called natural succession or ecological succession. 

Biodiversity

Another fundamental feature of the Atlantic Forest is biodiversity. The Atlantic Forest has so many species that we still have not managed to know all of them. In the forest, all species live in harmony with each other, each one performing its function so that the forest can perpetuate itself for many, many years. Biodiversity is the key to balance, as each species present is important to the ecosystem functioning. The greater the biodiversity, the more sustainable our production system will be.

Nutrient cycling

The nutrient cycling is what allows the forest’s soil to always remain rich and fertile.

. Plants take the nutrients they need to grow, live and bear fruit from the soil, but they also give back to the soil some of the nutrients they have used through falling leaves, twigs, or even when they die, having already fulfilled their function and their life cycle. All material that falls on the forest floor is transformed by decomposing agents, which through this process make the nutrients available again for other plants to use. Therefore, we must always favour the nutrient cycling process in agroforestry so that the soil can remain always rich.

Adopting all these principles to build our food production systems, we can have promising results, as it has been observed in the reality of family agriculture applying successional agroforestry in different biomes[1] (Amazon, Atlantic Forest, Cerrado, Caatinga). These examples in Bolivia [and many Brazilian states such as] Acre, Bahia, Goiás, São Paulo, and Pernambuco are based on the experiences of Ernst Götsch, who points out the following principles:

  1. to mimic the processes that occur in nature;
  2. it is necessary to understand the functioning of the place’s original ecosystem;
  3. just as one form of life gives way to another, creating satisfactory environmental conditions, one [plant] consortium also creates another (based on natural succession);
  4. to insert the species of interest in the production system within the successional logic, trying to guide ourselves by the evolutionary origin of that species (original environmental conditions, consortiums that usually accompany that species, its eco-physiologic needs, etc.)

Ernst reminds us that we should always ask ourselves: “what can I do to be useful in the place, and to become a loved one in the system?”

PRINCIPLES FOR THE PLANTING AND MANAGEMENT OF SUCCESSIONAL AGROFORESTRY

The method used in the implantation and management of agroforestry in question is an attempt to replicate the strategies used by nature to increase life and improve the soil. In nature, plants occur in consortiums (and not isolated from one another) and require other plants for optimal development. Likewise, in agroforestry, the cultivates plants are introduced into consortiums to fill all the niches, taking into account in this combination native or introduced for regeneration or introduced, as well as exotic species, well suited to local soil and climate conditions. In addition to combining species in space, we combine them in consortiums in time, as is the case in natural succession of species, where consortiums succeed one after another in a dynamic process, depending on the life cycle of the species. Another fundamental aspect is the introduction of high diversity of species, reproducing a quintessential feature of the Atlantic Forest. Still within the principle of maximising the sun’s energy (light), the forests have their species occupying different strata. Each strata has an optimal density, which favours the entry of light in the right quantity for the next strata below. According to Ernst Götsch’s observations on the patterns of natural forests:

  • to the emergent strata the ideal coverage is 15 to 25%;
  • to the high strata the ideal coverage is 25 to 50%;
  • to the medium strata is 40 to 60%;
  • to low strata the ideal coverage is 70 to 90%; and
  • for the ground covering strata, 100%.

For example, in a mature forest the jatobá tree (West Indian locust) is an emergent species and do not occur in a way that its canopies touch each other. On the contrary, the density of individuals is low and the canopy cover is approximately 15 to 25% of the area.

For a better understanding, I present the definitions below:

Consortium = a group of species that present similar life time, that is, that lasts more or less the same time in the system. Each consortium consists of species belonging to the same successional group.

Consortium 1 example: corn, climbing bean, sunflower and pumpkin.

Consortium 2 example: pineapple, cassava, pigeon and papaya;

Consortium 3 example: achiaote (Bixa orellana), ingá-de-macaco (monkey-inga – Inga sessilis ), pupunha tree (peach-palm – Bactris gasipaes) and guapuruvu (Brazilian fern tree – Schizolobium parahyba);

Consortium 4 example: ipê roxo (Pink trumpet tree – Handroanthus impetiginosus), juçara (a palm tree with edible heart – Euterpe edulis), mandarin, jaboticaba, coffee.

These consortiums can be further diversified with other species that perform similar functions. For instance, instead of a trumpet tree, an araucaria (bunya) tree could be used in colder or altitude climates. A jatobá could be used instead of a trumpet tree also fulfilling the same emergent strata role in this future forest. An complete agroforestry system must have all consortiums, ensuring the systems perpetuation over time and an increased consolidated quality of life (soil transformed by the accumulation of organic matter and biological interactions).

Strata = is the height of the plant in relation to the plants of the same consortium.

Consortium 1 example: corn (emergent strata), sunflower (high strata), climbing bean (medium strata) pumpkin (low strata) and watermelon (ground cover strata);

Consortium 2 example: papaya (emergent strata), cassava (high strata), what would be the middle stratum? And pineapple (low strata);

Consortium 3 example: guapuruvu (emergent), jerivá (high) (queen palm – Syagrus romanzoffiana), lady-finger banana (high / medium), ingá-de-macaco (medium), achiaote (low);

Consortium 4 example: pink trumpet tree (emergent), cedar (high), juçara (high), mandarin (medium), jaboticaba (medium / low), coffee (low).

A complete agroforestry should have all the consortiums growing at the same time, be quite diversified, with all strata, ensuring that the vertical space is well occupied and that the sun’s energy is optimally harnessed, with the highest possible production of biomass.

Density = is the number of individuals by area. It is recommended that annual and semi-perennial crops be planted in the same spacing technically recommended for them in monoculture. Tree species should be planted, preferably by seeds, in high density (10 trees per square meter – determined by empirical results). Over time, thinning is recommended to reduce density and allow the choice of more vigorous plants to continue developing in the agroforestry, while the cut thinning will produce organic matter, which means the activation of soil life and consequently, the intensification of the nutrient cycling.

The high planting density of trees offers an opportunity to enrich the system, favouring the input of organic matter and consequently streamlining life in the soil and nutrient cycling. The space that tree species occupy when young is much smaller than the space they will occupy as adults. Thus, thinking about optimizing the occupation of space over time, we must plant them in high density, so that we have more tree species at the outset, and knowing that only a few of them will reach adulthood.

Agroforestry practices should be cost-effective, so we need to think about how to reduce the need for nurseries to the maximum. It is better to plant trees direct seeding because there is less work involved and there is opportunity for the trees to develop in the best niche (soil, and combination of species). Transplanting tree seedlings causes stress to the plant and also does not allow for high density the planting, since producing seedlings is very laborious and expensive. Therefore, whenever possible, we should opt for no-tillage seeds in high density. As they grow, we thin to not exceed the percentage of canopy closure for each strata.

It is very important to allow the establishment of natural regeneration[2], since species that come to arise spontaneously in the agroforestry should be incorporated into the consortium and managed, contributing with a greater biodiversity, occupation of space and production of organic matter in the system. 

Management Practices

It is possible to accelerate the succession in an agroforestry using the management, which basically consists of:

Selective weeding

Herbaceous plants belonging to the early successional stages, which are already senescent or mature (having almost completed their cycle), are thinned or cut and deposited on the ground (chopped and dropped), sparing those more advanced in succession. Selective weeding is a way to fast-track the system, because by removing the “old” plants, which have already fulfilled their function, we are rejuvenating the system, that is, we are sending a “message” that the system is getting young again.

Tree Thinning

Tree thinning is the cut, at the base, of the less vigorous trees that were planted in high density. Thus, over time, this practice allows us to reach the recommended spacing for trees as adults. The thinning is also important because it allows us to select the plants that are best adapted to that micro-place, therefore, choosing the best adapted plants and giving them even better conditions to grow.

Pruning

Insofar as the species to be pruned respond positively to this intervention, pruning should be used to rejuvenate the system. In addition, we can also use pruning to correct the stratification in relation to other surrounding species[3] or to open up for light in a time that another species require light to flower (e.g. coffee or pineapple).

The criteria used for pruning should be succession. Thus, when a branch is dry, or even injured by insects or disease, or when the plant is showing signs of maturity or old age, it should be pruned, considering its strata, the architecture of the canopy and the relationship with the other plants in the surrounding area.

First use sensitivity: pruning has to result in a more vigorous tree in the appropriate context compared to other species. We must respect its original shape, but we can direct it to meet our needs, encouraging vertical growth when we want timber or increasing the size of the canopy when we want more fruit. We must begin by taking away everything that is old or is attacked by ants and other insects; then we prune the lower branches that are not very healthy or are atrophied. Then we open to air and provide greater light input. We prune the excess, but always looking to maintain a balance in the form.

In addition, the quality of the pruning operation is very important to ensure the perfect regrowth of the plant. For this reason we need to be careful so that the branch does not chip or crack. This can be achieved with the aid of a saw (when the branch is thick) or very sharp knife, moving from the bottom up (when the branch is thinner).

The pruned material should be deposited, preferably at the bottom of some plant (without touching its stem) and covering the soil well, after selective weeding has been made on the spot. It is not recommended to deposit organic material on top of live plants. When a tree fulfils its function, and another one of a future consortium is established and developed, the tree that has already fulfilled its function can be cut down and the trunk and branches can be used for firewood, timber or construction poles, or else all its material deposited on the ground to be recycled. Also when tree thinning is needed because they were planted in a high density, the cut can be made very low so that one can use the timber or to organize the organic matter to cover well the soil, always placing more woody and ticker braches in contact with the soil and the finer material such as leaves and twigs on top.

These practices fast track the natural succession, leaving no room for regression causing by the onset of individuals of species that belong to the early stages of succession.

In the management of the successional agroforestry, all efforts are directed to recycle and increase the amount of organic matter produced, as well as to increase the quantity and quality of life consolidated in the place.

From the conception that agroforestry is an organism that works as part of an intelligent system, insects (considered pests in conventional agriculture) and microorganisms (which cause diseases), act to optimize life processes. So our role is to understand what is happening when a “pest” or “disease” occurs and not blindly seek to combat it. In a well-managed and diversified agroforestry there are practically no problems with “pests” and “diseases”. Diversification of species also provides a favourable environment for birds and insects that feed on phytophagous or herbivorous insects[4].

Example of an agroforestry system in a temporal sequence with species chosen for the reality of new and highlands of Acre (a Brazilian state in the Amazon region). These illustrations were developed by the Arboreto Project, Zoo-botanic Park, and Acre Federal University with the participation of local small farmers and Ernst Götsch in 2002. The art work was done by Darcy Seles:

Fig. 1 – approximately 4 months: corn, climbing bean and rice in the harvest phase (first crop). One could also crop okra, sesame, pumpkin, beans, tomato, etc.

 

Fig 2 – about 1.5 years: cooking banana, papaya and pineapple in the harvest phase (second crop). One could also crop in this phase, taro and air-yam, etc.

 

Fig 3 – about 5 years: lady-finger banana, pupunha, cocoa beans, cupuaçu (Theobroma grandiflorum), citrus, avocado already producing (and which will last a long time). Firewood and other fruits can also be harvested at this stage. Game begins to arrive and the soil is alive with organic matter from all previous harvests and pruning.

 

Fig 4 – about 18 years: lady-finger banana still in production, pupunha, bacaba (Oenocarpus bacaba), cacao beans, cupuaçu, cajá (Spondias monbin), bacuri (Platonia insignis), and rubber tree in production. Also in this stage jabuticaba, coffee, and many other fruits are yielding, in addition to timber, firewood, fibre, medicinal plants, oils, etc. Game is more intensely present.

 

Figure 5 – approximately 40 years: the agroforestry system is a mature, very productive forest. It continues to produce bacaba, cacao, cupuaçu, cajá, bacuri, rubber tree, Brazil nuts, in addition to many other fruits, hardwood timber, firewood, material for handicrafts, medicinal plants, oils, etc. Game is abundant and the topsoil has high fertility, with high levels of organic matter and intense biological activity.

In this sequence there is an abundance of life, food and other raw materials. The soil is becoming ever more fertile, with the addition of organic matter and biological activity. The porous soil welcomes rainwater, which supplies the water table, and the agroforest evapotranspirates creating rain. Moreover, much carbon has been sequestrated to the soil.

If we understand that a forest is a mosaic of clearings of different ages, we can think of the landscape or property as a mosaic of agroforestry systems at different stages of development. In this way, by using the consortiums, it is possible to crop species in the early stages of succession (e.g. rice, maize, beans) in a plot and other plants such as cassava, papaya, passion fruit in another plot, and in plots more advanced in succession, firewood and timber. When a system reaches its maturity, it is possible to start again, having enough organic matter and excellent soil condition as a result of our productive activity, to grow the important species for our diets.

Sensitivity and observation are essential in the practice of agroforestry. It is very important to perceive the landscape to act, to understand how things work, to be open, to observe, to learn from nature. Often we close our channels of communication, of perception, but we still have this capacity, if we practice and use all our senses.

Below are some technical aspects relevant to the successful implementation of agroforestry systems:

  • choosing soil and climate appropriate species (in relation to fertility and humidity);
  • Planting all the full consortia (considering plants with short, medium and long life cycles, and low, medium, high, and emergent strata),
  • use high density and diversity planting in high diversity and density;
  • establish all consortiums complete with plants from all stratas and life cycles;
  • accumulate organic matter in the system through selective weeding and pruning, and do not use fire;
  • manage as to streamline the system and accelerate the succession process (stratified pruning[5] and rejuvenation[6])
  • pay attention to the so-called pests and diseases, which indicate that we are either doing something wrong in the agroforestry or needing to manage it;
  • the short-lived herbaceous and vine plants are also part of the succession groups and must therefore be part of the agroforestry.

If we clearly understand the concepts, we can be ever more creative in our quest for autonomy. Agroforestry gives us the opportunity to be co-creators and artists, functions that dignify and reconnect the human being with nature.

For more information on the subject, see www.agrofloresta.net, where you will find texts, audios, videos, photos, and information on the Mutirão Agroflorestal (Agroforestry Working Bees), among other successional agroforestry-related things.

Upcoming Agroforestry Courses

     Forestry in Practice – With nearly 30 years of experience and literally thousands of farm plans under his belt, Darren J. Doherty comes to the Northern Rivers (NSW, Australia) to teach the course “Forestry in Practice“. The course equips farmers to holistically integrate trees in their landscapes and enterprises. Darren, who also works closely with livestock producers, has been an adamant promoter of tree integration for all farm enterprises. The course will runon the 9th and 10th of February, 2019, at the Holos Regenerative Design learning site in Brunswick Heads, Northern New South Wales.

 

RECOMMENDED BIBLIOGRAPHY

Fundação Rureco. Agroflorestas: semeando a vida em nossas lavouras. Guarapuava: Ed. Unicentro.

GÖTSCH, E. Homem e Natureza: cultura na agricultura. Recife: Centro Sabiá, 1995. HABERMEIER, K. & SILVA, A. D. Agrofloresta: um novo jeito de fazer agricultura. II ed.

Recife: Centro Sabiá, 2000.
SOUSA, J. E. Agricultura Agroflorestal ou Agrofloresta, Recife: Centro Sabiá, 2000. VIVAN, J. L. Agricultura e Florestas: princípios de uma interação vital, AS-PTA, Guaíba:

Agropecuária, 1998.
VAZ, P; TELLES, L. Agroflorestando a Terra: aprenda com a natureza a criar sua roça sustentável. Associação de Programas em Tecnologias Alternativas, 2003.

Footnotes

[1] – Biome: large plant formations, found in different continents, mainly due to climatic factors (temperature and humidity) and related to latitude.

[2] – Natural Regeneration is the spontaneous appearance of species that comes to assist in the process of natural succession for the establishment of the forest in a given area.

[3] – Pruning will not change the original strata of a tree. In other words, although one can keep a tree shorter through pruning (perhaps to facilitate harvest), that tree’s specific sun, shade and density needs cannot be changed by pruning (note done by the translator).

[4] – Phytophagous or herbivorous insects are those who feed on plants.

[5] – Stratified pruning refers to the pruning of trees respecting the strata that each tree occupies and its relationship with the other species in terms of height.

[6] – Rejuvenation pruning concerns the pruning of aged plants, after fruiting to sprout new shoots and as a consequence leave enough organic matter covering the soil.