An ethnobotanical study of the less known wild edible figs (genus Ficus) native to Xishuangbanna, Southwest China

Xishuangbanna (XSBN) is in the south of Yunnan province, southwest China, bordering Myanmar and Laos. It has an area of almost 20,000 km² and is biogeographically located at the transitional zone with tropical Southeast Asia to the South, subtropical East Asia to the north, the Sino-Japanese floristic region to the east and the Sino-Himalayan floristic region to the west [19]. There are three seasons: a cool and foggy winter (November–February), a warm and dry ‘summer’ (March–April), and a warm and wet monsoon season (May–October). The region possesses an exceptionally diverse flora and 13 indigenous cultural groups have well-established ethnobotanical knowledge. Ficus is the most species-rich genus in the region [19], with 69 species, subspecies or varieties native to the area [20]. Because of their close relationship with natural forests, all the native culture groups in XSBN have developed knowledge systems related to the use and conservation of natural resources. Wild collection is traditionally an important subsistence activity. Four ethnic villages near natural reserves inhabited by Dai, Hani, Jinuo and Yao people were selected as sample sites (Table 1). The exact locations of the sample sites are withheld to protect the anonymity of the interviewees.). For each village, more than 95% of the villagers are indigenous. Relevant local markets were also visited.

Field investigations were designed to assess the availability of edible fig resources, including their field distribution and home cultivation. Since the mountain villages (Bakaxiaozhai, Dazhai and Nanbang) do not have private homegardens, they consume only wild Ficus. We chose Nanbang as a representative mountain village to assess the distribution of the fig individuals they use. Six key informants were asked to guide field travel in the area surrounding their village in March 2012. Ficus individuals in dietary use and within one-hour walking distance (along twisting narrow footpaths in five directions) from the village site were recorded, including their species names, the numbers of plants, and their diameters at breast height (DBH). We chose “one-hour walking distance” to include most plots where the daily collection activities happen and the distance was accessible for all of our local guides. The Dai, who settle in valleys, basins or on river banks at lower elevations, are the major culture group in XSBN and have developed diverse homegardens. Most Ficus parts they eat come from these or from around their courtyards. We visited 107 households in Manlun village in May–June 2012 to collect data regarding the species, numbers of plants, and DBH of all edible Ficus species cultivated.

Observations of trading in Ficus products were conducted in three local markets related to the selected villages. They are the farm products market of 1) Menglun township, 2.2 km to Manlun and 5.7 km to Bakaxiaozhai, 2) Mengla township, 31 km to Nanbang, and 3) Jinghong city, which assemble farm products and wild collections from multiple ethnic groups and wide areas. All the villages can access their markets by motor vehicles. We selected Menglun market for long-term (November 2013 to April 2014) monitoring to collect basic data (species, price, sources, etc.) and determine the amounts sold and peak season, because the market has the most diverse Ficus products and modest size. We did market survey in Mengla and Jinghong during peak season to assess the universality of the trading activities. Only part of the result is shown in this study. More details on the amounts sold and their sources will be included in another publication because it needed additional investigations.

Based on the usage intensity classification for wild fruits of Chen et al. [18], we defined five levels of usage intensity according to our work described above. The five levels are coded as 1) –, no usage record; 2) +, consumed occasionally or just by children and hunters; 3) + +, frequently consumed and often gathered regularly during harvest season; 4) + + +, frequently consumed and the surplus may be sold in the local market or processed for out-of-season use, sources protected; 5) + + + +, cultivated in homegardens for consumption and sale.

All voucher specimens collected in our field work were deposited in the herbarium of the Xishuangbanna Tropical Botanical Garden (HITBC), Chinese Academy of Sciences.

Thirteen edible Ficus species or varieties and their corresponding local names were recorded. For F. maclellandii var. rhododendrifolia and F. vasculosa, the details were collected from the local markets. For the other 11 species, information was obtained by interviews of key informants in the four sample villages. The pronunciations of the Mandarin and ethnic names were recorded as accurately as possible in the Chinese phonetic alphabet (Table 2).

In the Dai language, names of wild plants used as vegetables are often preceded by “pàk”. The words “liāng” (reddish), “xiū” (green), “háo” (white), “núi” (smaller) and “lōng” (bigger) are often added to discriminate the edible parts of similar fig plants. Some Ficus forms distinguished by local people are apparently not yet recognized taxonomically. Sometimes, the flavor is reflected in the plant name. For example, the Dai word for chicken, “gái.” is used in the Dai name for F. vasculosa, describing the chicken-soup like taste of the young leaves used in vegetable soup.

In the Jinuo language, “neme” refers to leaf buds with a sour taste and “adao” is the common name for leaves. In the Yao language, “nuoge” is a common name for edible plants with white latex. The words “lumu” and “zamu” refer to “bigger” and “smaller” fig fruits. “Biu” is a common name for edible fruits, and “den” means young leaves or leaf buds.

All four culture groups use the young or ripe female figs and young leaves or leaf buds of multiple Ficus species as fruits, beverages or vegetables, with only minor differences in modes of consumption. Surplus young female figs of F. auriculata and young leaves or buds of six species are sold for cash income in local markets (Figure 1). Generally, the appropriate harvest season for young leaves or buds is late winter to summer and for fruits the monsoon season (Table 3), but there are exceptions to this timing under both natural conditions and with human intervention, such as frequent pruning to prolong the crop life of young leaves or buds.

Mountain villagers in Nanbang retain and protect the wild edible Ficus trees growing around the village in situ, and sometimes transplant individuals away from new farmland or road construction sites. Seventy four individuals of 7 species or varieties growing within one-hour walking distance from the village were recorded, mostly with a DBH of 0.10-0.15 m (Figure 2a). The villagers increase the production of young leaves and leaf buds by pruning during or out of the harvest season.

In the basin village of Manlun, 4 edible Ficus species and 1 variety were cultivated and 70 households (65% of the total) had them. The trees were grown in kitchen gardens or in and surrounding the home yard (Figure 3b, c, d). They were grown from branch cuttings or from seedlings transplanted from nature, except that most F. racemosa and a few F. virens individuals grew spontaneously from seed. The number of Ficus individuals owned by each household range from 1 to 9 (Table 4). Most are young trees and their DBH is less than 0.1 m (Figure 2b). The other two cultivated species, F. maclellandii var. rhododendrifolia and F. vasculosa, were not found in Manlun but in two other Dai villages according to the people who sold them in the market. Field surveys showed that F. maclellandii var. rhododendrifolia was planted as individuals by some households (Figure 3a), while F. vasculosa was planted in groups of small trees that can be managed and picked like tea (see lower part of the photo in personal cover page), so they are also known as “tea-leaf vegetables”.

Among the 13 edible Ficus, five species (F. auriculata, F. oligodon, F. semicordata, F. semicordata var. montana and F. virens) are common to all four culture groups. Only two of these (F. auriculata and F. virens), however, are cultivated for home and commercial use, and reached the highest usage intensities (+ + + +). The other four “+ + + +” species (F. callosa, F. maclellandii var. rhododendrifolia, F. vasculosa and F. virens var. sublanceolata) are mainly used by Dai people (Table 5).

The Dai, Hani, Jinuo and Yao represent four distinctly different cultural groups with different languages in XSBN. All four groups have accumulated extensive knowledge on using the female fruits (For dioecious fig taxa, only the female fruits are edible, they are seed producers and are larger in size, rich in nutrient and have a pleasant taste, while the male fruits function in breeding pollinator wasps are poor in nutrient and not palatable. For monoecious fig taxa, their fruits are the same and avoided by people because small size, poor taste and the presence of wasps), young leaves or leaf buds of Ficus species as food resources. The common consumed species across the four groups are F. auriculata, F. oligodon, F. semicordata, F. semicordata var. montana and F. virens. The wide consumption and sustained marketing of these species show that they are widely accepted food resources rather than a narrow cultural preference. All the species had fixed and usually food-related ethnic names, which indicates the long history of indigenous consumption.

Different cultural groups use the wild edible Ficus species to different extents, depending on their availability, the group’s dependence on forest resources, and cultural factors. Generally, the Dai people use them at the highest intensity because (i) they have been permanent inhabitants in XSBN for centuries, and have established homegardens for small-scale wild food or medicinal plant cultivation or domestication, and (ii) they live in basins and have better access to markets. The other three mountain culture groups have more recently established permanent living spaces in the region and do not have a culture of homegarden cultivation, depending more on forest collection. Our data show that the Hani people in Nanbang prefer fruits of F. auriculata and F. oligodon (“Xibu”). One of their orally transmitted legends tells that the first Hani people were born in a “Xibu” and survived by sucking the “milk” in it (the milky latex that characterizes figs). In addition, their ethnic epic records that “Xibu” is one of the first edible fruit plants they discovered in the forest during hunting activities. The villagers do not like strangling figs, such as F. alltissima and F. virens, since they often encounter huge strangling figs in the forest which have killed their host trees, and believe this is an omen of disaster. They therefore remove most of spontaneous seedlings around the village.

The possibility of a wild plant resource continuing to meet both subsistence and market demands largely depends upon sustainable harvest by appropriate management, and the domestication of wild resources is crucial for resource management [22]. Domestication of common fig is thought to have started in the Mediterranean region in Early Neolithic period [3] and then spread worldwide. In XSBN, the Hani, Jinuo and Yao protect wild edible Ficus species while the Dai cultivate them. Except for the species traditionally cultivated in or around courtyards for ornamental and consumption purpose (such as F. auriculata), the cultivation of most Ficus species was triggered by the expansion of rubber plantations and resulting sharp decline in wild resource accessibility since the early 1980s. The indigenous villagers prefer to plant these species for their wide adaptability, high productivity, easy management and pleasant palatability. Ficus species are cultivated as tree fodder in many parts of the Himalaya region, with F. auriculata the most widely used species. Its fodder quality is far superior to paddy straw [23]. In the Bamileke region of Cameroon, Ficus species are propagated by pole cuttings and are an important part of agrarian system management [24]. These examples show that wild Ficus species undergo a gradient of management intensities from simple gathering, to nonselective incipient management, selective incipient management and occasionally ex situ cultivation [25]. But whether or not the incipient domestication has occurred is unknown.

The commercialization of wild edible Ficus species in XSBN is an important source of cash income for indigenous villagers. The leaves, buds and fruits of several Ficus species are sold in local markets and the whole plants are sold as ornamental trees. In other regions, however, only in north and central Vietnam are the near-ripe peeled or unpeeled fruits and young leaves of elephant figs (F. auriculata Lour. or F. oligodon Miq.) on sale in the market, and in Papua New Guinea the young leaves of dinner-plate figs (F. dammaropsis Diels.) are commonly sold in highland markets [8]. As Sawian et al. [26] reported, these products seldom appear to contribute a large share of a household’s total income generation, but are often important in bridging seasonal or other cash flow gaps.

The use of wild Ficus species as food is widespread in areas where the genus occurs, especially in the Himalaya region, which is floristically similar to our study area. For the 13 edible Ficus species in this study, the consumption of 6 species has either not been reported from elsewhere (F. altissima, F. callosa, F. maclellandii var. rhododendrifolia and F. vasculosa), or only from South China (F. tikoua and F. virens var. sublanceolata). Consumption of the other 7 species had been reported from Nepal [7, 27] and some were reported as eaten in India [9, 13, 28, 29], North Laos [18], Vietnam [8] or Pakistan [16, 30].

No other region appears to consume the diversity of wild Ficus species eaten in XSBN. Moreover, in the species consumed only in XSBN as well as those used most intensively, leaves and buds are the major parts consumed. These are concentrated sources of vitamin E, vitamin B₁ (thiamin), vitamin B₂ (riboflavin), protein and minerals [31], and are apparently also rich sources of naturally occurred antioxidants [32], suggesting that they may make a significant contribution to the health and well-being of the consumers. Antioxidant potential has also been demonstrated in some other Ficus leaf samples [33].