Designing the Forest Succession

When conducting the process of reforestation we may consider two kinds of trees;

The support species, in charge of creating the nurturing framework of the forest ecosystem (soil fertilization through nitrogen fixation with leguminous plants, strong root penetration for soil breaking, nurturing and ventilation, rapid biomass production for mulch production and topsoil reconstitution, wind breaking and moisture capture, etc.) and

The productive species, in charge of food production for human and animals and side products generation like timber, fibers, etc.

At start 80% of planted trees, bushes and cover-ground are leguminous (support species) in order to boost the ecosystem capability to develop, and 20% of productive species are planted taking into account their capacity to adapt and resist to the first years of a non fertile and often dry environment. The support species are planted in various sizes and  over-density and will be pruned or removed over time to produce mulch and allow productive species to receive light.

How to proceed in term of design

80% of the support plants, mainly leguminous, will disappear, either naturally or pruned or removed, to create mulch and biomass.

The design needs to show on paper the species that will stay in fine in the food forest. They are mostly productive species and 20% of supportive species (for fertilization, wind break, mulch production, etc.) The location per zone of the different productive trees needs to be defined.

Then if the support species can be spread in the field surrounding densely the productive species they don’t really need to be included in the drawing since they form a nurturing placenta evenly distributed.

The distribution of support species may be compared to the construction of a grid, mixing homogeneously the different supportive species in size and shapes. Later the landscape architecture will operate negatively and remove the unnecessary plants.

It is on one part; classical landscape drawing, in the other; design by negative space in the landscape architecture. The supportive species which will remain (not been removed) are plants with particular positive interaction, health and robustness and capability to act as a permanent species, in size, shape and adaptability (pruning recovery, propagation capability, weather adaptation, …).

In Time

With regard to the time scale it is to be considered that some (most ?) productive species have poor pioneering qualities and will be able to settle only after a buffer of time, requiring the protection and the fertilization from pioneer species.

In this case either you have resources and may invest for each plant enough organic fertilizer, enough labor (modify the soil texture at the plant location if necessary), enough biomass to ensure global moisture and carbon availability, enough money to invest in infrastructure, e.g. “Groasis Waterboxx” See external resource.

or you may schedule the plantation following some strategies;

– Pioneer productive species are planted at the same time than the support species, at start of the reforestation . They will not grow quick but will resist and settle, ready to use in the future the resources provided by the support species.

– Productive species will be planted following a calendar based on their need for fertility, humidity and protection and on the resources available. The calendar is based on global fertility of the land improved over years by the support species and on the different specificity of the various location (An outdoor shower will provide with constant humidity, an existing tree will protect from the sun, a roof may concentrate rain falls or help to water zone 1 by rain water harvesting, etc…). Resource location (swales, pond, compost, chicken tractor, dry toilets, etc.) is as well key in the way to orchestrate plantation over time.

– Recent studies show that reforestation at large scale is better done by planting clusters of trees and not spread them homogeneously. The many small forests will nurture their close environment and help the settlement of trees in their peripheries, till the clusters extend and reach each others. As an habitat for seed gathering animals the tree cluster will support biodiversity in the forest propagation.

In space

A domestic variant of the cluster distribution is to stretch vegetation in strategic directions once settled. Various techniques can apply;

– If you have the capability to harvest branches and leaves (3rd / 4th year) you may over-stack the soil in between the sun course and the tree cluster, close to it, with pruned material. The material must be 1 meter high ideally and will protect the young seedlings from the sun and represent a reserve of biomass fertilizing the soil and keeping moisture. The presence of the tree cluster will provide with fertility on its periphery and wind absorption.

– On the other side, where the shadow of the tree cluster bring humidity and cool down the temperature seedlings do not need a lot of attention and no mulch is needed. The growth is the most reduced where the shade is the most intense.

Other fountains of resources (gray water treatment, swales, dry toilets, stable, ponds, etc.) can see their flow orientated in order to nurture vegetation extensions. In this case the slope play a determinant role associated with the sun course.

In all cases the prevailing wind and wind sectors need to be taken into account in the stretching directions.

Knowing the result in space and time of the stretching process for every tree cluster or resource fountain, this knowledge can be used to anticipate the design and influence the location of the resource fountain and tree clusters themselves.

New plantations are done at the start of the humid season. Exception can happen for zone 1 where watering can be done easily.

Flora

Leguminous species

Large : Acacia Mangium (see reforestation with Acacia Mangium)…

Middle size : Inga Edulis, Leucaena, Samsao do campo…

Small size and vines : Pigeon Pea, velvet Beans, Jack beans, Crotalaria…

Cover-ground (perennial) : Amendoin Foragera…

Some pioneer productive plants:

Mango, Jackfruits, Acai, Coconut trees, Dende, lemon tree…

Plants needing a fertile soil:

Banana trees, papaya, amora, goyava, caja, graviola…

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