Plants as highly diverse sources of construction wood, handicrafts and fibre in the Heihe valley (Qinling Mountains, Shaanxi, China): the importance of minor forest products

Background Chinese rural communities living among species-rich forests have little documentation on species used to make handicrafts and construction materials originating from the surrounding vegetation. Our research aimed at recording minor wood uses in the Heihe valley in the Qinling mountains. Methods We carried out 37 semi-structured interviews in seven villages. Results We documented the use of 84 species of plants. All local large canopy trees are used for some purpose. Smaller trees and shrubs which are particularly hard are selectively cut. The bark of a few species was used to make shoes, hats, steamers and ropes, but this tradition is nearly gone. A few species, mainly bamboo, are used for basket making, and year-old willow branches are used for brushing off the chaff during wheat winnowing. Conclusions The traditional use of wood materials documented suggests that some rare and endangered tree species may have been selectively cut due to their valuable wood, e.g. Fraxinus mandshurica and Taxus wallichiana var. chinensis. Some other rare species, e.g. Dipteronia sinensis, are little used and little valued.


Background
Construction wood and firewood are the main products of modern forestry. However local communities living in woodlands usually implement multiple uses of the forest, also involving the production of utensils, medicine and food. The importance of minor timber forest products and non-timber forest products (NTFP) has been emphasized for decades in ethnobotany, forestry, rural development etc. Some of these products may have a vital non-commercial value,others enter the cash economy and improve livelihoods [1][2][3][4][5][6]. Ethnobotanical works, however, often overlook the lesser-used types of wood available to local populations, emphasizing only the "nontimber" part of the ecosystem. The minor uses of wood are more closely documented in older ethnographic works. e.g. describing and documenting traditional tools and handicrafts, although the topic has also been touched upon by ethnobotany [7][8][9][10][11][12][13][14].
Chinese ethnobotany has been developing fast in recent years. However most papers are focused on traditional wild food and medicine, mainly among ethnic minorities. Although some papers are devoted to the issue of non-timber forest products in China [15][16][17][18][19], we observed a lack of studies concerning the ethnobotany of traditional handicrafts and other objects made of wood. In order to fill this gap we carried out a study in the Heihe National Forest Park in the Taibai range, Shaanxi province, China. Mount Taibai, the highest of the Qinling Mountains, is one of the most species-rich and valuable parts of nature in northern China. This area has preserved a rich woodland flora and fauna, which is well-studied. An area with a rich and welldocumented flora is an ideal working place for an ethnobotanist. Over the past few years some of the authors of this paper have devoted a few articles to the use of wild food plants in one of the valleys of the Taibai range, and the use and cultivation of the highly toxic Aconitum carmichaelii [20][21][22].
Our research aimed to document minor wood uses in the Heihe valley. By this we mean any uses of wood, twigs or branches of trees, shrubs, climbers and bamboo apart from large scale construction wood or firewood.
Both past uses (before the area became a national forest park) and present uses were recorded.

Study area
The study covers the Heihe National Forest Park (Fig. 1), on the southern side of the Taibai Nature Reserve, with the highest peak of northern China in the center of the reserve (Mt Taibai 3767 m a.s.l.). The nature reserve protects a highly diverse florafrom warm temperate (with subtropical elements), to alpine at the top. The National Forest Park (with a less strict protection regime) is adjacent to it, and mainly protects species-rich forests. The area is almost completely covered by ancient forest vegetation and rocky outcrops. The Heihe river valley belongs to the Houzhenzi administrative unit (town, zhen (镇)), with an area of 822 km 2 . It is a very isolated place, which has vehicular access to the county town of Zhouzhi (where the post-office and schools are located) only via a 2.5 h drive through a winding precipitous gorge, sometimes   The studied villages lie between 1000 and 1500 m a.s.l. At these altitudes the climate is temperate, with daily temperatures in summer oscillating around 20-30°C and winter temperatures around 10°C to -10°C. The mean annual temperature in Houzhenzi is 8.2°C, with a high rainfall of nearly 1000 mm, 44% of which is concentrated in the summer months. The dominant vegetation is the species-rich Quercus variabilis and Q. aliena var. acuteserrata forest, with an admixture of Pinus tabuliformis, and many deciduous tree species (e.g. Acer spp., Tilia spp.).
The majority of the local population are subsistence Han Chinese farmers who grow maize, potatoes, wheat and beans. Sources of cash income are the orchards of zaopi (Cornus officinalis), walnuts (Juglans regia) and northern Sichuan pepper (Zanthoxylum bungeanum). Digging out medicinal roots and collecting medicinal herbs for wholesale buyers is also a very popular activity. The importance of tourism is increasing. A significant proportion of farms are registered as agritourist farms (nong jia le). Most tourists come from Xian and its surroundings and are attracted by the beautiful scenery and hiking opportunities.

Data collection
The field research was conducted in the summer and autumn of 2016 using the Rapid Rural Appraisal approach [24,25], and included 37 freelisting interviews in seven villages ( Fig. 1), which involved 52 people altogether. This included 39 men and 13 women as the former were more willing to talk about this topic. The mean age of the participants was 55 (aged from 39 to 87).
The research was carried out following the code of ethics of the American Anthropological Association [26] and the International Society of Ethnobiology Code of Ethics [27]. Oral prior informed consent was acquired. The interviews were carried out in front of the dwellings of the interviewees in order to provide easy access to the tools and structures mentioned by the respondents. We asked the interviewees to list all the uses of wood, twigs or bark to make structures, tools and other objects in their own households and farms. This was the only question asked and at the beginning of the interviews no props were provided. At the end of each interview we asked to see the tools present in the yard, and sometimes more tree species were then mentioned (Figs. 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and 23). Additionally, discussion groups were organized to cross-check the identification of specimens. The listed taxa (Tables 1, 2 and 3) were identified using specimens collected by informants in the forest or in the village. The interviews were carried out in Mandarin Chinese, which is the first language of the local population.
The authorities of Houzhenzi Forest farm in Shaanxi Forestry Bureau in Xi'an and park rangers were also consulted about the conservation status of trees in the study area.    In order to measure the cultural importance of particular wild foods we used Smith's Salience Index [28]. The index for species A is the mean of the following ratio calculated for each free listed plant: Salience Index ¼ total no: of items in a list-rank order of species A starting from 0 for the 1st item ð Þ total number of items in a list Thus a species which is always quoted first gets an index which equals 1 and the items quoted at the end of the freelists tend to have Smith's indexes close to 0.
Voucher specimens of plants were deposited in the Herbarium of the Northwest A&F University in Yangling (WUK). Plants were identified using the standard identification key concerning local floras, and their names follow the Plant List [29].

Results
Altogether, 84 species of plants were recorded as material for construction and handicraft plants (Tables 1, 2  and 3). Of these, 80 species are used for their wood and five species for bark. Two herbaceous species and two bamboo taxa were used (  Table 3). The ranking of most salient species is nearly identical to that of those most frequently mentioned ( Table 2).    All the large-sized tree species are used in some form by the local inhabitants. Among shrubby species and small trees those which have very hard wood are used to make handles, walking sticks or small objects like forks and harrow teeth. The bark of a few species was used to make shoes, hats, steamers and ropes, but this tradition is nearly gone. A few species, mainly bamboo, are used for basket making and year-old willow branches are used for brushing off the chaff during wheat winnowing. The use of large pieces of local timber has greatly diminished due to the protection regime, and is now limited to the trees growing in the land around houses. On the other hand, the wood for such objects as tool handles, bee hives, walking sticks and carrying sticks is still commonly used from local trees.
We recorded a few dozen emic categories of use. The most frequently mentioned categories were listed in Table 1. A few of the most commonly used tree species have many uses, but among the trees used with medium frequency some have very specialized uses restricted to one particular application. For example Morus australis is the preferred wood for carrying sticks (a stick where two buckets are attached on each side), Philadelphus incanus for making walking sticks, Castanea mollissima for electricity poles, Cotinus coggygria for making small boards supporting ceramic tiles in the roof, Tsuga chinensiscoffins, Meliosma dillenifolia and Cornus kousatool handles. Pinus spp. is used for the main construction of houses, windows and doors. The materials for making chopping boards and rolling pins are more diverse, though for the former Prunus stellipila and for the latter Buxus sinica is preferred. Firewood is usually collected from any available wood, though Quercus and Betula are preferred. All the households contain many self-made wooden tools. These tools are usually made only for farmers' use and are neither bought or sold. Such items as furniture, coffins, handles or shovels are still commonly made. On the other hand the manufacturing of bark shoes disappeared in the 1980s and we could not find a single such shoe preserved in the valley, although many people still know how to make them. The production of wooden barrels is also dying out.

Discussion
It is difficult to compare our data with other places in China as similar studies are lacking.   One of the factors which makes the sale of wooden items hard, even for those skilled in making them, is the protection status of the surrounding forest. No commercial large scale logging has been performed in the area since 1987, when it was designated as a water resource area for the city of Xi'an. Wood is only cut for local purposes for farmers' use. The monitoring of timber use is important for forest conservation [30][31][32]. Our results suggest that some rare and endangered tree species may have been selectively cut by local people due to their valuable wood, e.g. Fraxinus mandshurica and Taxus wallichiana var. chinensis. Some other rare species, e.g. Dipteronia sinensis, are little used and little valued.
All the local large canopy trees are used for some purpose. From among smaller trees and shrubs, those which are particularly hard are selectively cut. From all the larger trees more common in the area, Pterocarya is used the least. It is also striking that only one species of Acer was mentioned, although a few other species of this genus grow in the forests. They tend, however, to grow above the villages, at slightly higher altitudes, and they are not attractive due to their shrubby growth. Some   The use of smaller tree species is also very common, as they usually grow on farmer's parcels. According to regulation no. 32 in chapter 5 of the "State Forest protection Laws," [33] private trees in farmers' parcels around their dwellings can be utilized by local residents, even in National Forest Parks. For example, local people planted a plantation of Cornus officinalis on their own land for money, but in recent years the price of the fruit of this species has become very low. So many people felled the C. officinalis plantations and the wood was used to make tools or firewood. According to the information we got from the nature conservation authorities local residents occasionally get permission to cut Castanea trees in the state part of the forest for the construction of bridges, whereas construction timber is now imported from outside the park borders. The demand for construction timber has also been diminished by the use of non-wooden construction materials (e.g. concrete). Some wood is also available to local residents as a leftover from forest management (e.g. removing trees attacked by pests).
It is very striking that hardly any superstitious beliefs were recorded when talking about trees. No trees were treated as particularly lucky (auspicious) or unlucky, as is very common in other parts of the world [34], and despite the presence of such beliefs in the traditional fengshui system [35].
Although some plant uses are well known, probably across large parts of China, particularly those concerning large hardwoods used for construction and furniture, or bamboo (see e.g. [36], some uses of rarer small trees and shrubs in handicrafts may be endemic to this part of China, and be worth recording.