The Korqin Sandy Lands are geographically located between 117°15' and 123°43' Eastern Longitude, and between 42°20' and 44°50' Northern Latitude, on the alluvial plain of the Western Liaohe River Basin, southeast of the Greater Khing'gan Mountains Range and north of the Yanshan Mountain Range.
The Region is composed of the following administrative units:
Inner Mongolia Autonomous Region:
Banners of Chifeng City: Aohan, Wengniute, Right-Balin, Left-Balin and Alukorqin;
Banners of Tongliao City: Naiman, Kulun, Kezuohou, Kailu County, Korgin District, Zhalute and Kezuozhong;
Keyouzhong Banner of Xing'an League;
Jilin Province: Tongyu County of Baicheng City;
Liaoning Province: Zhangwu County of Fuxin City.
The total area of the Korqin Sandy Lands, as considered in this study, is 189,000 km2, forming the major natural landscape type in the Western Liaohe River Basin.
The main residents in the Region are farmers and herdsmen of the Mongolian, Han and other ethnic groups, who have long since been engaged in grazing and extensive farming activities. Excessive population pressure and irrational farming practices have led to desertification in certain areas.
The eastern part of Korqin Sandy Lands is lower than its western part. Its western part inside Wengniute Banner has an elevation of around 600–700 meters, while the elevation of its eastern part in Kezuohou Banner is only about 250 meters. Most sand dunes occur in ridge-like shapes, running from West-Northwest to East-South-east, as a result of the main direction of the winds. The relative height-difference among sand dunes is normally between 3 and 10 meters, with some sand ridges and wave-shaped hills under 3 meters. The area and proportion of lowlands among sand dunes also increases gradually from west to east, reflecting a gradual difference in precipitation and moisture content of the sandy land from west to east.
The Korqin Sandy Lands are under the relative influence of the Southeast Maritime Monsoon Atmospheric Circulation System, resulting in a relatively moister climate compared to the sandy lands on Inner Mongolian Plateau.
The average precipitation is 340–520 mm, depending on sites, while average relative humidity varies between 38 and 61% and the annual average temperature ranges from 4.9 °C to 7.1 °C. The number of days with temperatures equal or superior than 10°C varies from 148 to 167. The annual sunshine amounts to 2836–3170 hours, and the annual frost-free period is 133–183 days long.
The climate of the region is classified as warm and semi-arid in the temperate climatic zone. The wide fluctuations in the level of precipitation over the years are increasing the threat of desertification.
The following table shows the climate situation in the relevant banners (counties).
Table 1.2.1: Meteorological Information of Banners/Counties in Korqin Sandy Lands
|Name of bannerscounties||Annual average temp. (°C)||No. of days >10°C||Accumulated temp. of days >10°C||Time of sunshine (hours)||Frostfree period (days)||Annual average precipitation (mm)|
|Inner Mongolia Autonomous Region||Chifeng City|
|Liaoning Province: Zhangwu County||7.1||167.4||3295.2||2836.6||154.7||519.5|
|Jilin Province: Tongyu County||5.1||154.0||3021.7||2927.0||145.0||405.7|
The sandy soils of the region are developed on the basis of eolian sand deposits and are loosely structured and highly susceptible to wind erosion when disturbed by human intervention. Marked thermal differences exist between day and night at the soil surface: during daytime, the surface heats very fast under sunshine (ground temperature of bare sand reaches up to 40–50 °C in summer) while over night the soil surface temperature falls drastically.
Many plant species in the Region, have developed fibrous sheaths or lignified dead tissue around their lower stem as a protection against these temperature changes.
Accumulation of organic matter in these sandy soils is slow, and most have a very low content of organic matters and low fertility. Due to the larger particle-size of sandy soils, no granular structures are formed. Capillarity is low and permeability high, allowing rain to percolate easily into the ground.
The underground water movements are relatively easy and only a limited proportion of the water is evaporated. The aquifer of the soil is abundant, providing a good supply of water to the plants.
Although the Korqin Sandy Lands are located in a semi-arid climatic zone, due to the abundant underground water supply, vegetation succession has lead to a combination of open woodlands, shrub lands and grasslands.
The ecological succession on sandy land is totally different from the grassland eco-system that developed in the same region, but on different soils. The succession and evolution process in the Region can be divided into the following stages:
a pioneering stage with bare and semi-bare moving sand dune,
semi-stabilized sandy land with grasses and shrub species,
stabilized sandy land with semi-shrubs and shrub phytocoenose,
a more stable and more complex phytocoenose with open woodland, shrubland and grassland.
The Korqin Sandy Lands are located in the transition between China's Northeast flora and the Mongolian flora. Vegetation composition presents features of the Changbai Mountain flora and of the North-China flora, as well as of the Dawuli Mongolian flora. Great Green Valley, in the extreme southeast of the region, boasts features of many different flora, and is by far the richest part of the Korqin, in terms of biodiversity.
According to a study by Cao Xinsong et al. (1964), there exist about 450 species of higher plants in the Korqin. This figure is more comprehensive than the 421 encountered by Yong Shipeng et al. (1985). About 300 species have been found in the sandy land areas outside the Great Green Valley, 210 species inside, while about 60 species are found both inside and outside the Valley.
The plant populations of Fraxinus mandshurica and Betula ovalifolia found inside the Great Green valley are typical representative of Changbai flora, while Quercus mongolica is the climate climax type of the Northeast China broadleaf woodlands, belonging to the East Asia flora.
Six major vegetation community types are distinguished:
annual pioneering plant communities, with Agriophyllum squarrosum as the major species. Some communities also include such species as Salsola collina, Bassia dasyphylla and Corispermum sp. These annual plant species bear a large quantity of seeds, disseminated by wind over vast areas. Being very invasive, they constitute pioneering plant communities on bare sandy land and moving sand dunes. They can be of practical value to stabilize sand.
rootstock grasses communities, with Agropyron desertorum on sand ridges. The most commonly associated grass is Pennisetum flaccidum, with Calamagrostis epigeios and Carex duriuscula among others.
semi-shrub community, with Artemisia halodendron as most typical for the Korqin (semi-) stablizing moving sands. This is a species with a strong capability of regeneration, both through seed and vegetative propagation. The average plant height is 40–60 cm; crown diameter is 60–100 cm, with a well-developed root system up to 2 m deep. This is a very important plant species in sand movement control.
drought tolerant thorny shrub community: the representative species is Caragana microphylla, often mixed with Artemisia halodendron and Hedysarum fruticosum, forming a community type, which stabilizes sand. Due to its well-developed and deep root system, it has a strong sand-binding effect. It is also a very good source of fodder for goats. Some of this species grows associated with Ulmus pumila to form open woodland.
medium height shrub community: the main species are Prunus armeniaca, Rosa dahurica, Ribes diacantha and Atraphaxis manshurica, which have a sand-binding function, and relatively high ecological, environmental and economic values.
open woodland community: in Korqin, three main types of sandy land open woodland communities are distinguished. The most widely distributed type is the Ulmus pumila open woodland. The other types are: the Hemiptelea davidii open woodland and the Ulmus macrocarpa open woodland, in the eastern part. The Open Woodland Community is the end stage of sandy land vegetation succession. Together with shrubs and grasses, open woodland shrub grassland is formed, being the vegetation type with the most diversified ecological functions and the highest resource values. The open woodland holds promise for the ecological rehabilitation of the Korqin Sandy Lands, allowing a complex management system, incorporating agriculture, woodland-based forestry and animal husbandry.
During its long history of formation and evolution, several species belonging to three genera of the Ulmus-family have developed in the Korqin Sandy Lands: Ulmus, Hemiptelea and Celtis. Their characteristics are described in the following paragraphs.
1.5.1. Ulmus pumila L.
U. pumila has, with the changes that have occurred in its geographic surroundings, developed into a widespread species. It is found in the temperate zone in Asia and Eastern Europe, within the range from 30° to 48° Latitude North. In the arid and semi-arid areas of Central Asia, it prospers on river terraces and in valleys, due to the presence of groundwater. On sandy grasslands, it forms Elm open woodland-grassland, using underground water. This vegetation type is found in the Korqin Sandy Lands and the Hunshandake Sandy Lands over large areas.
The U. pumila open woodland-grassland in the Korqin is showing different degrees of degradation, due to long-standing over-utilization. Growth is slow, regeneration poor and trees are crooked or shrub-like, due to damage caused by cattle and sheep.
U. pumila is a xeric mesophyte, very intolerant species, resistant to drought, cold hardy and light-demanding. The branches and leaves provide good fodder. U. pumila open woodland-grassland is a high quality fodder base for cattle and sheep herds. The samara of U. pumila contains 3.8% of proteins, 1% of fat, 8.5% of sugars, 1.3% of coarse fiber and 82% of water.
The crown of the tree is nearly round or oval. Bark is dark gray, coarse with longitudinal cracks. Branches are thin and colored. Leafs are oval-egg to oval-lanceolate shaped, 2–7 cm long, with the base-end almost symmetrical, the leaf edge with single saw tooth and a lateral vein with 9–14 pairs. No downs or clustering downs appear on vein axes. Flowering occurs before leaf-growth with hermaphrodite flowers, clustering, 4 calyx fissures and 4 stamens. Samara is nearly round shaped or oval, kernel at the center of the samara, 1–2cm long, yellow-white at maturity. Flowering period from occurs from March to April while the samara reaches maturity from May to June.
The timber is of high quality, hard with a beautiful grain. It is utilized for the manufacturing of furniture and plywood.
This species has a great potential for the rehabilitation of open woodland in sandy areas with an annual precipitation between 300 to 400 mm. If well tended, including man-assisted regeneration, and if adequate management practices are carried out, an open woodland with a canopy coverage of 10 to 20% of the total area may be expected to be formed.
1.5.2. Ulmus pumila L. cv. pyramidalis
U. pumila cv. pyramidalis is originally from Meng County (Henan Province) and was obtained through breeding. Its trunk is straight, and the branches slope upward with a small angle, forming a relatively narrow canopy. Its growth is fast, and the timber is relatively soft and loose in structure. It is widely planted in North China, due to its straightness and fast growth. Tongliao Municipal Nursery has set up a provenance base.
1.5.3. Ulmus macrocarpa Hance
U. macrocarpa is mainly distributed in humid and semi-humid areas in East Asia, but can be found on sunny slopes in the woodlands in Northeast and North China. It is a xeric mesophyte, usually shrub-like and associated with Prunus armeniaca (Siberian apricot) on low hills. This species is in the Korqin mainly found in the areas surrounding the Daqinggou Valley.
U. macrocarpa has a gray-black colored bark, small branches with two stripes (rarely four) of cork wings. Leaves are oval, about 5–9 cm long, base-end asymmetric, edges saw-toothed, and both sides of the leafs are coarse with short and stiff hairs. Samara are big, nearly oval, 2.5–3.5 cm long, 2.2–2.7 cm wide and haired with a kernel in the center of the samara. Flowering period occurs from March to April, while samara mature from May to June. Its branches and leaves are not palatable.
U. macrocarpa is a unique tree species, adapted to sandy soils in Northeast China, distributed in the western part of Jilin Province, Tongliao City and the Xing'an League of Inner Mongolia, Nenjiang District of Heilongjiang Province, as well as in the mountainous areas of Fengning County in Hebei Province. The U. macrocarpa woodlands in Xianghai Nature Reserve in Tongyu County of Jilin Province occupy the largest area (16 000 ha). This Reserve constitutes a valuable reserve of high quality U. macrocarpa genes, which can be utilized for further development.
The species is very cold hardy and drought-resistant, tolerant to poor soils, and resistant to pests and diseases. It has excellent characteristics for sand-fixation and for use in windbreaks. Due to its beautiful shape, it is suitable for ornamental plantings in cities and countryside and it can be used along roads. Its timber is of high quality, with a high oil-content, and it is used for construction and shipbuilding. Woodlands of U. macrocarpa shelter some rare bird species.
U. macrocarpa is a native species in the region and the main tree species of the natural secondary woodlands, which include other tree species such as U. pumila and Hemiptelae davidii. It is also associated with shrub species such as Periploca sepium Bunge, Tamarix chinensis Lour, Prunus armeniaca and Lespedeza bicolor, among others. Under this woodland cover, representative plants of the herb-layer are Cyperaceae, Leguminosae and Compositae, such as Ephaedra chinensis Tourn. ex L., Saposhnikovia divaricata Schischk, Tribulus terrestris L., Glycyrrhiza uralensis Fisch., and Bredia oldhamii Hook f.
U. macrocarpa usually grows well at the bottom of sand dunes and can develop into tall trees, reaching up to 17 meters high with a DBH of 35 cm. When on the top of the sand dunes, trees are mostly shrub-like, and the taller the dune, the shorter the trees.
The genetic variation of the species itself and differences in site conditions have brought about big variations in the individual characteristics of the trees, such as stem form and length (from shrub-like to straight and tall), branch-angle (from the drooping type with angles over 85° to less than 30°), branch-shape (from slim over thick to tender), crown-shape (from round over cylinder to drooping), bark (from shallowly to deeply cracked), and the size and shapes of the leaves (early from small 5 by 3 cm, to big 12 by 10 cm).
U. macrocarpa buds on average end April, flushes early May, grows leaves around mid May, stops leave-growth late August, starts leaf color-change in the second half of September, and starts leaf-fall in October. The total growing period is about 121 days, but the lower the latitude, the earlier the budding date and the later the growth-stop and the growing period becomes correspondingly longer.
From budding till the end of May is the period during which U. macrocarpa grows the fastest. The speed of growth starts to slow afterwards. During the fast-growing period, the increase in diameter may occur in 1 or 2 main periods, and the increase in tree height in 1 to 3 main periods.
There are many high-quality varieties in the natural secondary woodlands waiting for utilization. Fast growing varieties with straight trunks have a potential for the establishment of timber woodland and shelterbelt woodland and those with drooping branches, for ornamental purposes.
Superior varieties include numbers 022, 025, 024, 037, 039, 043, 044 and 041, selected by the Baicheng Academy of Forestry (Zhang Yuqi) from the natural secondary woodland in Xianghai Nature Reserve of Jilin Province. Feng-1, Feng-2 and Feng-3 are selected from Fengning County in Hebei Province. Feng-4 is from the Research Institute of Shelterbelt Woodland in Heilongjiang Province.
1.5.4. Ulmus davidiana Planch.
U. davidiana is distributed in Northeast Asia, and is found in the mountains of North and Northeast China, the Far East of Russia and in Korea. It usually grows in a temperate humid and semi-humid climate, and belongs to the mesophyte, intolerant, cold-resistant species.
It is the major tree species of the open woodlands in the eastern part of the Korqin Sandy Lands, forming a beautiful park-like wood-grassland, providing good ecological protection of great scenic beauty. In this part of the Korqin, with an annual precipitation between 400 to 450 mm, it can be planted mixed with other tree and shrub species to reconstruct the open woodland.
The timber is of high quality with a beautiful grain, very suitable for furniture-making and construction purposes.
1.5.5 Ulmus laevis Pall.
U. laevis is a species that thrived in the temperate humid climatic zone of Europe, after the glacial period of the Pleistocene on the Eurasia Continent. It has been introduced in Xinjiang, North China and Northeast China. The planting in Tongliao City has also been successful. This species has the potential to be widely used and promoted in the Korqin Sandy Lands for afforestation.
U. laevis has a tall and straight trunk. Its growth is fast, and the timber is of high quality.
1.5.6 Ulmus laciniata Mayr.
U. laciniata is distributed in East Asia, and can be found in North China, Northeast China, the Far East of Russia, Korea and Japan. In the Korqin Sandy Lands, it is found in the western part, north to the Yanshan Mountains. It is a species of a humid climate.
1.5.7 Ulmus japonica Sarg. (U. propinqua Koidt)
This species is found only in the humid valley bottom and lower slopes of the Daqinggou Nature Reserve. Its bark is gray-white, juvenile branches are light gray-brown finely haired, sometimes with asymmetric cork-wings. Leaf is obovate or oval, 8–12 cm long with the upper-end sudden-short pointed, the base-end wedged or nearly circle-shaped, asymmetric, edges saw-toothed. The upper-face of leafs is coarse with short and hard hairs, underside is gray down and vein axil with clustering down. Samara is obovate or egg-ellipse shaped, 1.5–2 cm long, without downs and a kernel near gaps of the samara wings. Flowering-period is from March to April and samara reaches maturity from May to June.
1.5.8 Hemiptelea davidii Planch.
H. davidii is distributed mainly in Northeast and North China and in Korea. It can be found in the eastern part of Korqin. It is a xeric mesophyte, intolerant tree or shrub. When well tended, it develops into a tall tree. This species has very strong sand-fixation capabilities.
1.5.9. Celtis bungeana Bl.
C. bungeana is distributed in North, Central and East China, the southern part of Northeast China, and Korea. A small part of the distribution area covers the eastern part of Korqin and the Daqinggou Valley. It is a mesophyte species with good timber quality.