CHAPTER TWO
ELM OPEN WOODLANDS IN THE KORQIN SANDY LANDS

Elm open woodland is a unique natural vegetation type in the sandy lands of North China, and is found only in Korqin and in the Hunshandake Sandy Lands. In Korqin, the Elm open woodland is the oldest and widest-distributed original vegetation. Over the years it has been seriously affected by destructive use and it is presently under the threat of over-conversion, over-grazing and felling. Whether the Elm open woodland should be protected or left as it is in order to disappear completely, is one of the key-issues concerning the ecological and economic environment of the Korqin Sandy Lands. To provide answers to these questions, it is necessary to study the characteristics, structure and functions of this vegetation type.

2.1 Distribution and characteristics of Elm open woodland

Elm open woodland has a wide coverage in the Korqin Sandy Lands. In May 1998, a survey organized by the Project 009 was conducted in the 12 banners (counties) of the Korqin Sandy Lands. Results show that 11 banners still have some distribution of natural Elm open woodland (see Table 2.1.1).

Table 2.1.1: Distribution of Elm open woodland in Korqin

Fixed sand dunes and undisturbed sand-sheet are the two major site types, while there is also some distribution on moving sand dunes and on disturbed sand-sheet. The total distribution area is about 415,000 ha, about 3.5% of the total land area of the Korqin Sandy Lands. Keyouzhong Banner has the largest distribution area, with Zhalute Banner, Kezuohou Banner and Kezuozhong Banner following.

2.2 History

It is remarkable that the Elm open woodland has been able to survive in the Korqin Sandy Lands over relatively large areas without any protection measures, notwithstanding the heavy pressure caused by human interference.

According to studies done by Qiu Shanwen¹, Zhang Baizhong² and Hu Mengchun³ et al, the Korqin Sandy Lands were formed during the mid-Pleistocene, about 730,000 to 260,000 years ago. Results obtained from pollen-analysis indicate that the area around Naiman at that time was covered by Elm open woodland and that this is the original vegetation type, and not the closed forest.

Studies by Wu Jihua and Zheng Xinsheng⁴ indicate that the Korqin Sandy Lands used to have other vegetation types, beside the Elm open woodland and grassland, such as the Quercus mongolica (Mongolian oak) mixed woodlands and the Pinus tabulae formis (China pine) coniferous woodlands. However, at present the Quercus mongolica woodlands and the Pinus tabulae formis woodlands are reduced to a few relicts, while the Elm open woodlands still have a relatively extensive coverage.

During the Holocene, starting 12,000 years ago, the vegetation of the Korqin was grasslands alternating with open woodlands and wooded grasslands. In the early times of the Neolithic age, about 8 to 9 thousand years ago, human activities first appeared in the region. The agricultural and animal husbandry productivity was low, the production scale small, and the damage to the environment limited.

With the development of agricultural production, damage to the environment also increased. However, by the time of the Liao Dynasty about 1000 AD., open woodlands with abundant grasses and ample water supply still covered the Korqin. The Liao Dynasty Emperors focused on the development of agriculture, and incentivated the population to migrate in order to speed-up the rate of land reclamation for agriculture. The over-the-centuries-accumulated soil fertility in the Korqin assured initially abundant harvests. Cities started to appear, and for a while the Korqin became a heavily populated area.

With the increase of the reclaimed areas, the environment of the Korqin Sandy Lands deteriorated drastically over a period of 200 years, and by the late Liao Dynasty (about 1100 AD) and during the Jin Dynasty (1127–1279 AD) desertification became disastrous, and most cities established during the Liao Dynasty were abandoned.

During the Yuan, Ming and Qing Dynasties from 1280 to 1850 AD, the political and economic center of the country moved southwards. As a result, human pressure on the natural vegetation in the Korqin became less severe and agricultural activities almost came to a complete stop. The main utilization became extensive grazing once again. Vegetation recovered quickly and by the 17th century the region was covered again with woodlands and grasslands.

However, during the latest two hundred years, the promulgation and implementation of certain policies and directives has caused again and repeatedly extensive damage to the Elm open woodlands of the Korqin Sandy Lands.

These policies and directives include the following:

• Lifting of the ban on Han people to travel outside of the Shanhaiguan Gate by Emperor Xianfeng (1851) of the Qing Dynasty, which led to an influx of people from adjacent provinces to the Korqin, and the beginning of a new era of conversion of the open woodland.

• The “Population Migration for the Development of Frontiers” policy (1858) decreed by the Qing Government, promoting conversion. Large areas of woodlands and grasslands were converted to agricultural land.

• The “Recruiting for Conversion” policy (1907), by the Qing dynasty, causing further intensification of the reclamation process.

• The “Land Reclamation Methods” and the “Regulations for Awarding Reclamation” decrees, promulgated by the Kuomintang Government, to encourage conversion for agricultural purposes. Land conversion and county establishment was also carried out by the Northeast warlord Zhang Zuolin (“Land Reclamation and County Establishment”)

• The “Food Being the Basic Policy” decreed after the founding of the People's Republic of China, caused further damage to the vegetation in the Korqin.

• Finally, the “Great Leap Forward” consolidated the destruction of the vegetation of the region.

Though desertification has been checked in certain areas by means of heavy investment and effort, the overall trend towards the deterioration of the ecological environment in the Korqin Sandy Lands is still not under control.

2.3 Natural vegetation succession.

One of the reasons for the survival of the Elm open woodland is probably that it is the climax community in the vegetation evolution of the Korqin Sandy Lands, with high stability and resilience.

In the early 1950s, Liu Shen'e⁵ described the end-stages of the natural vegetation evolution process, near Zhanggutai: Ulmus - Prunus armeniaca or Lespedeza bicolor Turcz (shrub stage) - Leymus chinensis and Agropyron cristatum dry grassland (fixed sand dune). He denominated it the “Dry Ulmus Woodland System”, meaning that the vegetation will develop into Elm open woodland after the fixation of sand dunes.

Liu Yingxin et al.⁶ proposed the following vegetation succession in the Korqin Sandy Lands:

• Agriophyllum squarrosum first appears on the drifting sand dunes -

• Salix gordejevii Y. L. Chang -

• Pennisetum flaccidum Grieseb., Calamagrostis epigeios, Agropyron cristatum, Leymus chinensis

• Ephaedra Tourn. Ex L., Cerasus humilis, Prunus armeniaca, Lespedeza bicolor Turcz,

• and finally Elm open woodland.

A research team⁷ sent by the Chinese Academy of Sciences in the 1970's to Inner Mongolia and Ningxia divided the sandy land habitat into the following categories according to the succession stage of sandy plant communities and the fixation degree of the sand dunes:

• drifting sandy land: vegetation types include pioneering flora such as Agriophyllum squarrosum, Pugionium cornutum Gaertu. and Corispermum sp. L. ;

• semi-fixed sandy land;

• fixed sandy land: vegetation types include Agropyron cristatum grassland, Cleistogenes serotina Keng grassland, Caragana microphylla Lam. shrub and Elm open woodland.

Nan Yingao et al.⁸ made the following proposal, after studying the sandy land vegetation in Wulan'aodu and Baiyintalai:

• drifting sand dune stage: annual pioneering flora such as Agriophyllum squarrosum and Corispermum L.;

• semi-fixed sand dune stage: Salix gordejevii Y. L. Chang communities;

• fixed sand dune stage: Caragana microphylla or Atraphaxis manshurica Kitagawa communities, which will be replaced by Elm woodlands later.

Zhang Qiang⁹ states “Elm open woodland is the typical climax community in the vegetation succession on sandy grassland. Due to the relatively favorable water conditions here, its climax community is a stage more advanced compared to the climax community developed on typical not-sandy soil in the same region, and can thus form open woodland.” (see photo 29)

Contributing to the resilience and stability of the Elm open woodland, are the biological characteristics of the elm species, which have in comparison to other species of the region, a relatively high demand for heat, but little for humidity.

2.4 Types and structure of Elm open woodland

Elm open woodland in the Korqin Sandy Lands is usually composed of two layers - trees and herbs - or three layers - trees, shrubs and herbs. It can be divided into the following 7 types:

• Ulmus pumila open woodland,

• open woodland with U. pumila plus shrub grassland,

• U. macrocarpa open woodland,

• open woodland with U. macrocarpa plus shrub grassland,

• open woodland with U. pumila plus U. macrocarpa,

• open woodland with U. pumila plus U. macrocarpa plus shrub grassland,

• Hemiptelea davidii open woodland.

The following is a more detailed description of the structures of these seven types of Elm open woodlands.

2.4.1. U. pumila open woodland

Open woodland with U. pumila is the type with the most extensive distribution and largest area in the Korqin.

Research plots to study the horizontal distribution and vertical structure of this vegetation type were set-up in 7 banners (counties). The following table provides information on the results of the observations on the 8 plots established in the U. pumila Open Woodland.

Table 2.4.1.1: Structure of the U. pumila Open Woodland

As can be observed, the distribution pattern of open woodland with U. pumila presents two types of spatial distribution: clustered and randomly distributed individual trees. Crown-coverage is mostly under 50%, tree density is about 50 individuals (or clusters) per hectare. In certain places, the density can reach up to 230 trees (clusters) per hectare and crown-coverage up to 100%. These sites usually are superior, with little or no human interference.

To study the population-structure, size structure has been adopted as basic tool, instead of age structure, due to lack of information on ages. The following standards were adopted to classify elm-tree sizes:

• Seedling: height less than 0.5 m;

• Young tree: height between 0.5–2.0 m;

• Small tree: DBH between 5–15 cm;

• Medium tree: DBH between 15–25 cm;

• Big tree: DBH larger than 25 cm.

In considering this site classification, it should be borne in mind that the Elm open woodland in Korqin Sandy Lands has undergone a long period of over-grazing, which has stunted tree-growth.

The results show that the population size distribution in the plots are different and that four types may be distinguished.

Furthermore, trunk shape (see Table 2.4.1.2) of the remaining trees is very poor, due to the effects of a negative selection (meaning that the best trees are systematically felled). The growth of U. pumila is generally short and stunted with very few big trees over 10 m high. Over 60% of the individual trees have crooked trunks, resulting in a low timber value.

Table 2.4.1.2 : Stem form of U. pumila.

(U. pumila open woodland)

2.4.2. Open woodland with U. pumila plus shrub grassland

This type of open woodland has an extensive distribution in the Korqin. Two major species associations may be distinguished:

• U. pumila with Caragana microphylla

• U. pumila with Prunus armeniaca shrubs, with relatively high density and dense crown coverage.

Both the horizontal and vertical structures are well diversified.

Table 2.4.2.1: Structure of Open woodland with U. pumila plus shrub grassland

I: individual random distribution pattern;
C: clustered distribution pattern.

The following table provides information on the stem form and branch-free length.

Table 2.4.2.2 Stem form of U. pumila.

(Open Woodland with U. pumila plus shrub grassland)

2.4.3 U. macrocarpa open woodland

This vegetation type is mainly distributed in Tongyu County of Jilin Province; there is also a large area in the Xianghai Nature Reserve (Tongyu County).

The structure of this type is shown in Table 2.4.3.1

Table 2.4.3.1: Structure of U. macrocarpa open woodland

This open woodland presents mainly a high density and good crown-coverage. Its size-structure is stable, with many small trees, few medium trees and no big trees. The stems of the U. macrocarpa trees are mostly crooked (over 80%). The underbranch height of the stem is only about 1 m. (see Table 2.4.3.2 Photo 30)

Table 2.4.3.2: Stem form of U. macrocarpa

(U. macrocarpa open woodland)

2.4.4 Open woodland with U. macrocarpa plus shrub grassland.

This association is mainly distributed in the Wusitu District of the Kezuozhong Banner. Crown-coverage, density and tree-height are relatively well developed (see Table 2.4.4.1). Prunus armeniaca, Lespedeza bicolor and Crataegus pinnatifida are well represented in the shrub layer.

Table 2.4.4.1: Structure of Open Woodland with U. macrocarpa plus shrub grassland

The location where this plot was established has been designated as a county level nature reserve.

The balanced size-structure of U. macrocarpa in the plot indicates that its population is of the sustainable developing type. Tree stems are mostly crooked (see Table 2.4.4.2).

Table 2.4.4.2: Stem form of U. macrocarpa

(Open Woodland with U. macrocarpa plus shrub grassland)

Due to the conservation efforts of recent years, the growth of herbaceous plants under the trees is abundant, with good ground-coverage. There has also been an increase of wild animal species such as wolf, fox and fowl. It is obvious from simple observation that the general ecological environment has greatly improved.

2.4.5. Open woodland with U. macrocarpa plus U. macrocarpa

This type of open woodland is found in the Kezuozhong Banner. Density, crown-coverage and height of U. pumila are all superior to those of U. macrocarpa (see Table 2.4.5.1).

The population size-structure of U. pumila shows that if overgrazing is controlled, a population with abundant seedlings, young and small trees and relatively fewer medium-sized trees will develop.

All the trees of U. pumila are crooked (see Table 2.4.5.2). Only very few trees of U. macrocarpa exist in the sample plots.

Table 2.4.5.1: Structure of Open Woodland with U. pumila and U. macrocarpa

Table 2.4.5.2: Stem form of U. pumila

2.4.6. Open woodland with U. pumila plus U. macrocarpa plus shrub grassland

This vegetation type is mainly distributed in the Daqinggou Nature Reserve in Kezuohou Banner. Tree species include U. macrocarpa and U. pumila, shrub species include Crataegus pinnatifida and Prunus armeniaca. Furthermore, there are over 20 species of herbaceous plants in the sample plots. The density of U. pumila is relatively high, with about 90 clusters per ha while the density of U. macrocarpa is only about 40 per ha. Nevertheless, crown coverage, height and DBH of U. macrocarpa are all greater than those of U. pumila (see Table 2.4.6.1).

Table 2.4.6.1: Structure of Open Woodland with U. pumila and U. macrocarpa plus shrub grassland

Compared to U. macrocarpa, U. pumila has a larger percentage of trees with crooked trunks (see Tables 2.4.6.2 and 2.4.6. 3).

Table 2.4.6.2: Stem form of U. pumila

Table 2.4.6.3: Stem form of U. macrocarpa

2.4.7. Open woodland with Hemiptelae davidii Planch.

This vegetation type is found over large areas only in Ji'ergalang of Kezuohou Banner. The density of this open woodland is relatively high, with 333 clusters per ha. The crown-coverage can exceed 40%; most trees are under 4 m high (see Table 2.4.7. 1).

Table 2.4.7.1: Structure of H davidii open woodland

The distribution pattern is clustered. Population size-structure indicates a developing population type. The characteristic thorns of H. davidii protect the tree from grazers, explaining the presence of large numbers of seedlings and young trees in the population.

Trunk-shape of trees above 1 m20 is 44% crooked and 56% relatively straight. Under 1 m20, the trees behave like a creeper. Young and small trees often are shrub-like.

One individual has been found in Bayasiguleng in Kezuohou Banner measures 12 m tall with a DBH of 67.0 cm, and a crown projection area of 260 m².

2.4.8. Comments on the population structure analysis results

Structure analysis of the populations of almost all of the described vegetation types, indicates that the Elm open woodlands in the Korqin are facing a serious lack of regeneration.

This situation is especially severe for the U. pumila open woodland, which has the largest distribution area. The lack of seedlings and young trees is worrying in relation to the future evolution of these populations: without regeneration they will gradually die-off and disappear.

In comparison, the mixed woodland type of U. pumila with other arbor or shrub species has a more balanced structure, with more seedlings, young, small and medium trees, indicating a more balanced population type. The reason for this may be related to the relative increase in biodiversity, increasing stability and resilience. Another more obvious reason is the presence of higher quality forage grasses in the U. pumila open woodland and the subsequent higher grazing-intensity.

2.5 Present use of the Elm open woodland

Inhabitants of the Korqin Sandy Lands utilize the remaining Elm open woodland for several purposes: grazing of herds, timber and fuel harvesting and as expansion area for agriculture.

2.5.1 Grazing

Elm open woodland is a good rangeland and has a long history of being used for grazing. There is a rich variety of high yielding forage grasses in the open woodland. The following table is based on figures cited in a book “Korqin Grassland In China” published in 1994.¹²

Table 2.5.1: Grassland productivity in the Korqin Sandy Lands

Note: 1 ha = 15 mu

Table 2.5.1 shows that the fodder-yield of the open woodland is the highest in terms of unit yield, edible unit yield and animal load.

Elm open woodland reduces the force of the wind, mitigates the damage caused by wind and sand and improves the microclimate. This is beneficial for the growth of an herbaceous plant-layer increasing ground cover. It provides shelter for livestock from wind or rain, and shade in summer.

Young shoots, leaves and fruits of elm trees are all high quality fodder. Elm leaves contain 6% of proteins, 0.6% fats and 9% of sugar. In every 100 gr of fresh leaves, there are 6.74 mg carotene and 0.38 mg lactoflavin, beside some vitamins. (Taken from the book “Ulmus pumila L.”¹³ Humans also consume fresh leaves and fruits.

Grazing reflects the importance of the Elm open woodlands but it causes at the same time severe damage to it. Most of the surveyed Elm open woodlands, are seriously affected by over-grazing, causing short or shrub-like, stunted trees with scarce leaves, poor growth and an almost total absence of regeneration in over 70% of the surveyed plots. The diversity of herbaceous plant-layer is poor, grasses are short with low density and coverage. Frequently, ever increasing patches of barren soil become visible with signs of wind erosion (see Photos 31 and 33).

This situation can be improved through adequate regeneration management, including the fencing-off of areas that are being regenerated for sufficient time to consolidate the trees above the reach of the grazers.

If this degradation process is not halted, the vegetation will further decline and turn into medium or heavily desertified land.

2.5.2. Wood Harvesting

Elms provide a high-quality timber. The mechanical properties of U. pumila are as follows: average volume compression rate 0.5%, compression strength parallel to grain: 380 – 400 kg/cm² and end-hardness is 460 – 530 kg/cm². The general wood-characteristics are good and the wood is rot-resistant. Its timber is widely used in vehicle- and boat-making, construction, and in manufacturing of agricultural tools and furniture.

The wood properties of U. macrocarpa and H. davidii are equally of high quality.

The wood-quality of elm is highly appreciated by the local population. The trees with the best stems are systematically and often illegally cut down. The continuing illegal felling is the main reason for the lack of big or medium-sized trees over large areas of Elm open woodlands. This does not only threaten the structure of the open woodland and reduce its functions, but also seriously affect the genetic features of the remaining elms, as the individuals with the least desirable characteristics are left standing (negative selection) This is undoubtedly one of the main factors contributing to the fact that most elms in the existing Elm open woodlands in the Korqin have poor, crooked and short trunks.

During this survey some tracts of Elm open woodland were found with trees having adequate trunk shapes for timber production. These areas are living examples of what could be achieved through a wise management of the existing elm resources (see Photos 35 and 36).

2.5.3. Land conversion

Reclamation of Elm open woodlands for agricultural uses has been very common in the Korqin Sandy Lands (see also chapter 2.2 on History). The main reason is that after hundreds of years of accumulation of organic material under the trees, shrubs and grasses of the open woodlands, the sandy soil gets improved and soil fertility increases, which in the short-run assures reasonable harvests. However, the mainly coarse particle-size of the sands and the loose soil structure result in low water- and fertilizer-containing capability. Under influence of the wind (Elm open woodland is mostly distributed in windy areas), organic matters and the smallest fraction of the sand particles are blown away leaving the coarser infertile particles. The blown away matter eventually causes environmental problems for millions of people in the big cities.

So, although the Elm open woodland immediately after clearing might give good harvests, it is definitely not suitable for large area reclamation. However, the survey found that conversion activities are on-going over wide extensions of land in the remaining Elm open woodlands (see Photos 32 and 34).

2.5.4. Summary

The main reasons for the decrease of the Elm open woodland over large areas, and for the occurrence and expansion of desertification, are:

• Over-grazing has led to the disappearance of seedlings and young trees, low yields of the grasses and reduced growth in trees, low soil-coverage, low biomass productivity, degradation of the vegetation and increased wind erosion;

• Illegal felling has damaged population structure, eliminating the bigger trees and negative selection has affected the future genetic potential of this vegetation type;

• Indiscriminate land conversion has not only thoroughly eliminated existing vegetation, but also disturbed soil-structure, which has in turn led to a decline in soil-fertility and to an increase of environmental problems.

It is clear that the main factor leading to ecological deterioration of the Korqin Sandy Land is desertification. The main cause for desertification is uncontrolled conversion and degradation through human pressure of the Elm open woodland. Without protection by vegetation-cover, the soil fertility disappears and the land is doomed to desertification.

2.6. Protection status, woodland based tourism and cultural values of Elm open woodlands.

The importance and significance of creating nature reserves for the conservation of biodiversity and eco-systems is widely recognized. Reserves provide additional benefits for the development of science, for education and to attract tourism.

There are currently four nature reserves in the Korqin Sandy Lands:

• Daqinggou in Kezuohou Banner,

• Xianghai in Tongyu County,

• Xinjiamu in Keyouzhong Banner and

• Wusitu in Kezuozhong Banner.

Though the primary purpose of these nature reserves was not the protection of Elm open woodland, the main eco-system in them is Elm open woodland. The survey shows that the Elm open woodland in the four nature reserves has a sustainable and stable population structure.

After the establishment of these nature reserves, biodiversity of both flora and fauna has increased. This is especially clear with the newly established Wusitu Nature Reserve. This area is half closed and grazing is totally banned inside. Improvement in eco-environment, increase of biodiversity, excellent tree-growth and grass productivity increase have all been obvious.

This strongly proves the point of setting up nature reserves for the protection of Elm open woodland to conserve the natural landscape and maintain the biodiversity of the Region and to stabilize the ever-progressing desertification. Additional benefits will be obtained from research, tourism and the educational and economic values of a well-managed eco-system.

Traditionally, population in the Korqin attributes special religious properties to the elm woodlands. Very often, older elmtrees are associated with the presence of graveyards, and these sites are protected by the local population.