Sustainability of Chinese medicinal herbs: a discussion

Demand for Chinese medicinal herbs has grown rapidly over past decades. Practitioners are starting to be concerned not only about the quality of the herbs they use, but also about their sustainability. This article discusses some of the complex relationships and divergence of interests among herb-market participants and looks at initiatives that can work towards a sustainable future for Chinese medicinal herbs. Introduction Sustainability ‐ or sustainable development ‐ is a strategy for living on our planet that uses its finite resources without exhausting or destroying them. This can only be achieved by shifting the focus from maximum yield and fastest growth to considering the health of the entire ecosystem ‐ developing, producing and growing only at a speed that does not destroy the system's balancing mechanisms.1 Since we ‐ as humans ‐ are part of the system, its sustainability is obviously in our own interests. This kind of development is necessarily slower than what can be pressed out of an industry or a system if maximum growth is the priority. As far as sustainability of medicinal herbs is concerned, it means that the quantity grown or harvested does not endanger the future survival of the source plant, be it by over‐gathering the wild population, over‐exploiting the soil and terrain or severely diminishing the genetic pool/biodiversity. A little history Prior to the 1950s, demand for Chinese herbs was considerably smaller than it is today, and their trade was more regional. Traditional herbal medicine was mostly taught in relatively small private schools in China, with fewer herbalists graduating and practising. From the 1950’s onwards, however, TCM (traditional Chinese medicine) was established as a subject of study and research at university level and began to form a major part of the newly established national healthcare system, alongside modern medicine. Even doctors of modern medicine were encouraged to study it. The number of people working with Chinese medicinal herbs began to increase dramatically, while at the same time the international trade in Chinese herbs grew ‐ initially mainly to Japan and Taiwan, then more widely. To be able to meet this ever‐increasing demand, researchers were sent out to discover 'new' herbs on the one hand and to find new alternatives for known herbs on the other hand. It was then that many herbs started to be cultivated outside their ‘daodi’ (traditional) area and the guidelines in the official Chinese Pharmacopeia on what part of the herb or which species could be used for wild‐gathered herbs were changed. For example, for Xi Xin (Asari Herba)2 and Lu Gen (Phragmitis Rhizoma) the whole plant was used rather than just the root, and the Aristolochia fangchi species began to be used for Fang Ji (called ‘Guang Fang Ji’). It was at this time also that many newly discovered medicinal herbs were added to the pharmacopeia with little prior research ‐ Aristolochia being just one example. Herbs gathered in the wild Currently between 75 and 90 per cent of Chinese medicinal plants species are gathered in the wild,3 with the result that few resources have been devoted to establishing what conditions (fertilisation, water needs etc.) these plants would require if they were to be cultivated. The reasons for this are purely economic; as long as the price of any medicinal is relatively low, almost no one will invest in trying to grow it. This has led to many medicinal plant species being over‐exploited, a situation that is not unique to China. International conservation organisations differ on how to deal with this,4 some recommending that all wild species be brought into cultivation, and others recommending ‘sustainable harvesting’, which means restricted wild gathering according to specific rules (see below). In China pharmacognosists and others try to encourage small local farmers or communities to experiment with the cultivation of potentially or actually over‐exploited medicinal plants that have not yet been cultivated. According to Professor Zhang Hao, one of the author’s pharmacognosy teachers in Chengdu, this work has become somewhat easier in recent years as farmers are beginning to notice the decline of wild herbs they had historically been able to gather to generate a little extra income. Often, to find them at all, they now have to walk greater and greater distances. Examples of these are Chong Lou (Paridis Rhizoma), Chuan Mu Xiang (Vladimiriae Radix), Qiang Huo (Notopterygii By: Nina