Outstanding Features

Yunnan, a remote mountainous province, is a complex and diverse socio-ecological system of national, regional and global significance. It is widely recognised as a biodiversity hotspot of the world and close to other global biodiversity hotspots, such as the Eastern Himalaya. Yet, viewed from a conventional economic development perspective, this region, rich in biological and cultural diversity and natural ecosystems of global significance, is inhabited by disadvantaged people with poor economic status. Yunnan is home to 25 ethnic groups, the highest diversity of ethnicity in China. Over a long history, the ecological and cultural diversity and its linkage with south-east Asia as well as interaction with other parts of China and the surrounding mountain regions in the Himalaya have nurtured a great number of ingenious upland agricultural systems. These include the traditional homegarden, upland agroforestry, silvo-pastoral, terraced paddy field, and shifting cultivation systems interspersed among the natural ecosystems. Amongst those various important upland agricultural heritage systems, the traditional swidden agricultural system of alder based rotation and inter-cropping is widely practiced by most ethnic groups in Yunnan.

The alder-upland rice rotation system has been practiced for centuries in western Yunnan. According to historical records, this system became a major upland rice production system in the Ming Dynasty 600 years ago and since then it had continued in its traditional form until the early 1980ies. It is conjectured that systematic planting of this nitrogen-fixing fast growing species with high quality leaf litter evolved as an adaptive mechanism enabling swidden agriculture where nutrient stress was severe, natural regeneration capacity was poor and land available was extremely scarce.

Various patterns of alder based agricultural system can be found in Yunnan upland. One of traditional alder based rotation systems is the practice of broadcasting seeds into swiddens (upland rice/ buckwheat fields) in every 8 to 12 year's shifting cultivation cycle. Local Han, Wa, Jingpo, Dulong nationalities have practised this pattern for centuries. Farmers have accumulated rich knowledge and management techniques for different phases of the cycle. Collection of alder seeds, alder clearing, land preparation, seed broadcasting, upland rice harvesting are all very labour intensive and require the cooperation of villagers. Elder and experienced villagers guide the operation according to the agricultural calendar. During the land preparation and the alder cutting, most villagers gather and work on the upland. In the evening, they hold various cultural performances and exchanges ideas, knowledge and techniques.

With population growth and development of social economy, different ethnic groups have also innovated and developed various patterns with effective management knowledge and techniques from the traditional alder based rotation and inter-cropping system. The alder based inter-cropping and coppices system for the purpose of food security and fire wood consumption are both practised in north-east Indian and Yunnan Province of China. The upland people in Yunnan now intercrop alder with tea as the shade tree. In this system, Alder enhances the quality and output of tea by improvement of soil and the micro environment of tea garden. Additionally, alder litter (leaves and branches) are collected to make compost in many ethnic areas in Yunnan. A popular variant of the alder based system is to rotate or mix annual crops with other high valued conifer trees, such as Cunninghamia. lanceolata and Taiwania flousiala. Alder here plays a role of ‘keystone species' or ‘nurse species' in that it brings in micro-environmental changes which facilitate regenerations of other useful species.

In the past, farmers undoubtedly valued alder for its ability to rejuvenate fallowed lands, providing sustained yield of food staples and an abundant supply of firewood. Growing staple food crops was the main or core objective and the tree component was simply a means to achieve the goal of local production based food security from the swidden system. With most food needs now met by irrigated paddy lands and farmers, getting more and more influenced by the market economy, farmers have started to pay more attention to cash-generating opportunities. Under such circumstances they are likely to replace paddy by annual cash crops and/ or Alnus by timber trees with comparative advantages in the mountains. The annual cropping phase is now considered as a means to accomplish a standing crop of high-value timber.

Goods and Services Provided

The alder based agricultural system generates a wide range of environmental services. Apart from alder there are more than 350 other useful species, e.g. upland rice, buckwheat, corn, beans, Chinese herb (Ammomum tsao-ko), tea and animal species like buffalo, cow, pig, goat etc.

The traditional landraces of upland rice, buckwheat and other crops are part of indigenous culture. The traditional alder forest also serves as habitats for many native endangered species. The alder based rotation system promotes soil and water conservation and restoration through nitrogen fixation and litter decomposition. It improves micro-climate for production of tea and other crops. As alder grows fast and densely, it can be used to rehabilitate many deforested hills, especially those occupied by the invaded weed of Eupatorium adenophorum. Improvement in fast growing alder tree cover also means increase in carbon sequestration capacity of the hill ecosystems.

The alder based rotation system provides plentiful livelihood services for people's basic needs and consumption. The major products from the system are grain for food security; timber for house construction and furniture; firewood for household energy; green manure for making compost fertilizer, as well as other organic products, such as the tea, herbs, mushrooms, etc. The compost fertilizer reduces pressure for poor farmers to purchase expensive chemical fertilizers. This in turn helps reduce chemical run-off into international rivers in Yunnan. All those services provided by the system could help local people to enhance food production and income sources as well as to improve the quality of life, especially for the poor people living in remote upland areas.

Threats and Challenges

Recently, the alder based rotation system is being gradually replaced by other agricultural systems. The alder-upland rice rotation system remains only in a small scale in a few remote areas. The large patches of the alder forest have remained from the last broadcasting of the alder seeds in the upland rice in the middle of 1980ies. This traditional system of alder-upland rice rotation is facing the danger of disappearance.

The population growth reduces the per capita land resources. Land closure for nature reserves and rapid conversion of prime farmland into housing and construction, returning sloping farmland to forest all worsen land scarcity. On the limited land, the traditional system of alder-upland rice rotation every 8-10 years is unable to produce enough upland rice for food. With shortening of the rotation cycle the soil fertility cannot be recovered. As a result, local people have to search for other production systems to increase the food production. Alternatives include continuous and intensive agricultural production or intercropping of alder with food crops.

While the area for the traditional system of alder-upland rice rotation decreases significantly, the sustainability of new systems derived from the traditional practices is a concern.

The introduction of chemical inputs has replaced the need of nitrogen fixation and litter compost by alder to some extent. The food self-sufficiency in rural area is basically achieved on the prime farmland. The traditional food production system of alder-upland rice rotation on the rain fed fields is gradually converted into new systems of cash crop / economic tree production for income generation. Cash crops and economic trees include tobacco, tea, high-market value timber and other crops or trees. The large area of alder-upland rice fields are increasingly replaced by monoculture of cash crops, intercropping of alder and crop, and mixture or rotation of alder with other high market value trees. The area of upland rice is largely reduced and limited to rotation with other crops on the dry fields.

Policy and Development Relevance

One cannot claim that all practices that farmers have evolved with trial and experiences are ‘perfect' in all respect in the fast changing socio-economic-environment scenario and cannot be further improved. Scientific validation of farmers' practices can only reveal the scope of further improvement in their practices. The available research does not reflect on what should be the density of alder trees and what would be the most ideal spatial configuration of alder and annual crops. The compatibility between social and cultural systems and traditional informal institutions with the ecological processes is a key factor for long-term sustainability of traditional land use systems which have eroded in the recent past. Unfortunately, the inter-linkages between ecological and socio-cultural processes have received negligible attention from the researchers so far. The poor knowledge base in these respects means a risk of arriving at policy decisions which neglect or do not match with the local social and cultural values, and hence conflicts between the interests of local people and national/ regional/ global stakeholders.

Yunnan remains among the poorest areas in China. Development programs for poverty alleviation and infrastructure are increasingly implemented to push economic development in the region. At the same time, much attention is also paid to conserve rich and fragile ecosystems in Yunnan. Agricultural practices are undergoing a rapid transition, and are now subject to individual faming household's choice. The development program often involves introducing continuous and intensive production practices for quick improvement in food production and income generation. The challenge is how to conserve, adapt and integrate traditional rotational systems in the rapid transition in this region. Thus, one has to look into the question of what scientific research and policy interventions are required to build the capacity of local communities in evolving and practising land use systems that are environmentally sound as well as meet their requirements. Left to themselves, the indigenous farmers adapted to subsistence economy over generations may, under the influence of market forces, adopt practices which may not serve their long term sustainability interests or may even cause significant environmental degradation.

The push for converting this rotation and intercropping system into separate agricultural production and forest production fails to recognize that this rotation system can be an effective approach to meeting needs for food, income generation and forest rehabilitation. The knowledge and techniques of traditional practice of broadcasting alder seeds can also be used to rehabilitate vast deforested hills, especially those occupied by the exotic invader weed (Eupatorium adenophorum).

The alder based system is one of representative traditional agro-silvicultural practices in Yunnan; it demonstrates a sustainable way that simultaneously promotes rural livelihoods and environmental conservation in the upland areas. The elements of the system have good potential to contribute to poverty reduction through an environmentally friendly approach, which is a major objective of the local governments of Yunnan Province.

Global Importance

Different ethnic groups have developed effective management knowledge and techniques for different purposes with various patterns of the traditional alder based agricultural system. Some specific knowledge and techniques can be shared and replicated not only between various patterns within the system, but can also be used for other agricultural systems: for example to use alder leaves as organic manure for homegardens and terraced farming and as a model for alternative rotation agricultural systems.

The alder based rotation and inter-cropping system is widely practiced by many ethnic groups in the eastern Himalayan region, where several international rivers pass through. It has an important value for protection of watershed and unique biodiversity in this region. The alder based system represents one of many indigenous systems in this region that should continue to play a role for sustainable development. The wide use of the alder based rotation system and its associated crops in this mountainous region of global importance also provides a strong case of sustainable land use practices on mountain slopes.

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