Restoring Degraded Lands Worldwide
Assisted Natural Regeneration
Restoring Degraded Lands Worldwide
Assisted Natural Regeneration
Sometimes you don’t need to plant anything, just to assist the natural regeneration of land … we can be really transformational if we build the capabilities of communities to do it themselves.
Explaining Assisted Natural Regeneration
Assisted Natural Regeneration (ANR) is a simple, low-cost method for restoring forests that effectively converts deforested and degraded lands into productive ecosystems. Similar to Farmer-Managed Natural Regeneration (FMNR), ANR focuses on degraded forestlands and rangelands, while FMNR is practiced on croplands.
ANR aims to accelerate natural successional processes by removing barriers to natural forest regeneration. Instead of replacing the natural process, the method focuses on addressing obstacles such as soil degradation, competition with weedy species, and recurring disturbances like fire, grazing, and wood harvesting. Unlike conventional reforestation methods that involve planting tree seedlings, ANR offers significant cost advantages by reducing or eliminating the expenses associated with propagating, raising, and planting seedlings.
The Green Path to Productive Forests
ANR is most effectively implemented at the landscape level, restoring the protective functions of forests such as watershed protection and soil conservation. ANR techniques are flexible and allow for the integration of timber production, biodiversity recovery, and the cultivation of crops, fruit trees, and non-timber forest products in the restored forest. Preference for ANR may be given to areas where enrichment planting is carried out, favoring natural and local species used as sources of premium wood or non-timber forest products. In essence, Assisted Natural Regeneration provides a range of benefits:
- a cost-efficient way of regenerating forest
- job opportunities for communities
- strengthens biodiversity
- makes hunting areas available
- contributes to climate change mitigation by increasing carbon sequestration and carbon sinks
Transforming Lives and Landscapes
ANR'S Impact
The assisted natural regeneration of trees on community forest lands and grasslands has been widely recommended in Asia for over two decades. Despite its proven success, government forest departments have been slow to adopt ANR due to their historical focus on planting fast-growing timber trees in plantations. However, significant efforts have been made in the past few decades to develop and apply ANR approaches to forest restoration, with the potential to implement these methods across millions of hectares.
While knowledge of ANR has grown considerably, the technique is still under-appreciated and under-utilized globally. Limited efforts have been made to promote ANR on a mass scale. However, there have been some successful ANR initiatives in the Philippines, China, and other Asian countries. ANR has also been practiced in agroforestry systems in Brazil and woodlands in Zimbabwe since the mid-1980s. The most remarkable success story comes from the Shinyanga District in Tanzania, where ANR has significantly restored degraded land, improved incomes, and increased biodiversity.
The most dramatic and renowned success
The most dramatic and renowned success with ANR in Africa has been achieved in the Shinyanga District in northwestern Tanzania. When President Julius Nyerere visited the Shinyanga Region in 1984, he was shocked by what he saw. Decades of deforestation and inappropriate land management had turned Shinyanga into the ‘Desert of Tanzania.’ The president immediately launched a program to help tens of thousands of smallholders to restore degraded land, and in doing so to significantly improve their incomes.
The HASHI project revived the traditional system of land management that emphasized the assisted natural regeneration of trees on degraded forest and grazing lands, which increases the supply of livestock fodder for use during the dry season. When the work began, there were just 600 ha of documented ngitili – enclosed fodder reserves – in the region. Nowadays, there are over 500,000 ha of such reserves, regenerated through the application of ANR.
The ngitili provide fuelwood and building timber as well as livestock fodder. Their rapid expansion has brought about a significant increase in biodiversity, as species that had disappeared decades ago are now returning to the landscape. The economic benefits have also been considerable. One study calculated the total monthly value of benefits derived from the ngitili to be US$14 per person – a significant sum in rural Tanzania.
Farmers were also encouraged to adopt a range of other agroforestry technologies, including the planting of woodlots, fodder banks, and fertiliser shrubs. These, too, have yielded considerable environmental and economic benefits. The Shinyanga District assisted natural regeneration project was the recipient of the UN Equator Prize in 2001, awarded to recognise its community’s outstanding effort to reduce poverty through the conservation and sustainable use of biodiversity. The regeneration of the ‘Desert of Tanzania’ holds lessons that could be a basis for models that help transform lives and landscapes in many other areas, in Africa and beyond, which have suffered from serious environmental degradation.A participatory approach involving the local community in the HASHI project led to the discovery of traditional land management practices like the ngitili from the Sukuma people. The local farmers would set aside a piece of land to allow it to regenerate, especially during the onset of the rain season – and used only at the peak of the dry season when fodder supply is difficult.
Recovering Fertility Through Improved Fallows
A fallow is a piece of farming land left inactive for a season with no crops planted to let it recover its fertility. The principle of an improved fallow is establishing trees or other perennials in crop fields to regenerate soil fertility during the period when the fields are left fallow. One way of establishing such species is to manipulate the ecological succession of the fallow vegetation. Mexican sunflower (Tithonia diversifolia) is managed in such a way in Mindanao, Philippines, and Austroeupatorium inulaefolium is managed similarly by farmers in Sumatra, Indonesia.
Another alternative is to deliberately introduce soil-building tree species into the field during the cultivation cycle, before the field is fallowed, so that they will grow throughout the fallow period. After 2-3 years the trees are then cut down and the leafy biomass incorporated into the soil as preparations are being made to resume cultivation. The woody material is used as firewood or construction materials.
A variant of this is to maintain a dispersed population of trees in the fields during the cultivation cycle in order to accelerate the restoration of the soil health, as well as to provide useful products. There are many examples of this practice in the Asia-Pacific region, involving both leguminous and non-leguminous soil-improving species. These include Leucaena leucocephala, as used in a number of fallow-rotation systems in Indonesia and the Philippines, Sesbania grandiflora and other Sesbania species, and Alnus nepalensis in northeast India, southwest China and northern Myanmar. A prominent and very similar example from central America is the quesungual agroforestry system.
Extension programmes on improved fallows have been implemented in western Kenya andeastern Zambia, where these systems had received considerable research attention. Studies later showed that there was considerable adoption by Zambian farmers, where land availability was more abundant and fallowing was practiced. However, in western Kenya there was only limited adoption because the practice of fallowing was rapidly disappearing in the farming systems of that area, primarily because of population pressures and decreasing farm size.
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