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Agroforestry as a solution to deforestation

Publication Date: 21 Apr 2022 - By Chris B. By Chris B.
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Thematic Environmental, Social & Governance Impact/ SRI Global Agritech

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The social component makes a total stop on deforestation impossible, since local people often rely on the forest to generate an income. Therefore, set aside some special nature reserves the forests will continue to be used as they have been going back in history for a very long time. In the Amazon region for example recently discoveries were made that what was believed to be primary rainforest is actually secondary forest and has been used by humans for a long time but allowing for tree cover to remain and the forest to regenerate.

There is evidence that agriculture was conducted within and in harmony with the rainforest using practices that these days would be described as agroforestry.

Introduction to Agroforestry

Agroforestry is the practice of cultivating annual crops in combination with trees and sometimes livestock as well. During the past few decades interest in agroforestry practices has increased substantially. This is reflected in rising concern about deforestation and degradation of the environment. The accompanying decrease in land productivity and farm yields is becoming unacceptable, particularly in tropical areas.

The role of trees and forests in maintaining stability in ecosystems has come to the forefront in the search for solutions to environmental degradation. This, combined with the potential of trees as a source of many basic needs, has made it a priority, in recent years, of scientists and planners to look for ways to integrate trees and forestry into agricultural systems.

Agroforestry itself is not a new practice. Farmers have always incorporated trees in their farming systems, in many ways all over the world. However, in the so-called Western world, with the onset of rapid technological advances, trees became a neglected factor in agriculture. Monocropping, combined with widespread use of artificial fertilizers and pesticides seemed to be the only way to go. To some extent tropical areas have followed these practices as well, with disastrous results: soil erosion and degradation, declining yields and desertification are widespread. Recently agroforestry has been hailed as offering potential solutions to land use problems of tropical regions.

Benefits of Agroforestry

Traditionally what can be defined as agroforestry was used in subsistence farming, where select trees where cut for timber to cover building needs but tree cover was maintained whilst allowing for enough light at ground level to raise crops.

There are many benefits of agroforestry, but the two main ones are preventing of soil erosion and provision of nutrients to crops. In a tropical environment the topsoil is often shallow and prone to erosion. Clear cut areas in the Amazon for example will often have several years of good crop yield, but then the topsoil erodes, and the land is abandoned and converts to savannah, or worse desert. Maintaining consistent canopy cover assures that the root system of trees will protect the integrity of the topsoil. Additionally, crops can benefit from root decay: tree root systems can penetrate deeper mineral deposits not available in the topsoil and over time leach this nutrient to small plants at the top.

Typical cash crops that fare well under tree cover are cacao and coffee: Both actually benefit from tree cover as they grow better in light shade then full sun light. Coffee is often grown in conjunction with teak wood in a plantation system. In tropical areas the focus should be on conserving natural forests as much as possible. Silvicultural systems have been developed to allow for selective logging of select crop species whilst allowing the ecosystem to naturally regenerate, sometimes aided by the planning of saplings in the canopy openings or planting of crops shaded by the surrounding trees (agroforestry). The composition of the forest can also be altered to favour multipurpose trees, e.g. Brasil nut and Acai berries.

The special case of palm oil

Palm oil has been in the press a lot lately. Palm oil in itself is not necessarily unethical or unsustainable, but it’s the land use that is the problem. Given the world uses so much vegetable oil these days, driven partly by changes in diet, palm oil is actually an excellent choice given its crop yield can be up to 7-8 times higher than alternatives such as sunflower and rapeseed oil and therefore presents an effective use of land available. The problem arises that palm oil tends to do well in tropical regions close to the equator and therefore directly competes with the natural forests.

Whereas the focus needs to be on conserving remaining tropical forests, agroforestry can be a solution to regenerate degraded land with new but agriculturally productive tree cover. One benefit here is the hardiness of palm oil, it can grow well in full sun light and on depleted soils, but also still thrives under limited tree cover. Palm oil therefore can play a role both in land regeneration as well as in follow up agroforestry systems.

A system that would work well consists of tree layers and included livestock: Palm oil is planted initially to recover degraded land whilst protecting and promoting remaining tree cover and introducing new trees (initially fast growing and timber yielding species). Palm oil still grows well under partial taller tree cover and itself forms an interlocking second layer of canopy cover protecting the topsoil.  

Nutrients will still be deficient in this system, at least until the taller trees and their root systems have reestablished themselves. However, this can be achieved by natural means by allowing open spaces for life stock (e.g. cows) to roam and provide manure on the land. Social changes are necessary as this system works best in a cooperative of smallholders.

 

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