Eucalyptus Plantations in China - Bai Jiayu and Gan Siming

Research Institute of Tropical Forestry Chinese Academy of Forestry, Longdong, Guangzhou

ABSTRACT

The introduction, history and current situation of Eucalyptus in China from 1890 is re-viewed. China has the second largest (to Brazil) planting of Eucalyptus in the world. The policies adopted, and programmes carried out, have made considerable progress in scientific and technological studies and in practical production. To date some 460,000 ha of Eucalyptus plantations and 1.5 billion individual trees have been planted. Eucalyptus plantations are proven to bring highly positive effects on the environment, and also to accelerate the advancement of social, economic and cultural aspects.

Key words: Eucalyptus, China, afforestation, wind protection, tree breeding, biological diversity, industry, honey, leaf oil.

INTRODUCTION

The great majority of Eucalyptus species and subspecies are endemic to Australia, and these have been widely introduced and planted in many countries because of high adaptability and multiple uses. For instance, Eucalyptus has been in plantation use since first introduced in 1890. Now Eucalyptus plantations play an increasingly important role in China's ecological, social, economic and other aspects.

HISTORICAL BACKGROUND OF EUCALYPTUS IN CHINA

It is recorded that Eucalyptus was first introduced into China in 1890 for ornamental tree planting in parks or around villages and houses. Large areas of Eucalyptus plantations developed in the 1950’s. Presently, China’s Eucalyptus plantations amount to 460,000 ha apart from 1.5 billion individual trees planted around villages and houses and along road sides and canals, which makes the country the second largest in eucalypt planting area. The data does not include that of Taiwan (Zhong Weihua, 1993). China began introduction of eucalypts in southern, south eastern harbour and coastal cities, convenient for international traffic. Figure 1 shows early planting records (Qi Shuxiong, 1989).

Figure 1. Early records of eucalypt introduction in China

Source: Qi Shuxiong, 1989.

The early introductions were by foreign embassies in China, bringing eucalypts as ornamental trees from countries as Italy, France, etc. Some overseas Chinese contributed more later when Chinese diplomatic missions began introductions. “An Illustrated Introduction to the Eucalyptus”, written by Wu Zonglian, a Chinese Ambassador in Italy of the Qing Dynasty, is probably the earliest publication describing eucalypts in Chinese. The ambassador advised the Throne that eucalypts could grow in the southern area to the Changjiang River (Zhuang Miaochang, 1982).

In this early phrase, eucalypts were planted in gardens or along road sides. The earliest plantation recorded was established in 1935. Chen Jitang, a warlord in Guangdong Province, set up a kilometre long plantation of lemon scented gum (E. citriodora) along a highway in Hepu County, Guangxi Zhuang Autonomous Region (Guangxi Region). In 1960, 1,080 trees were still alive (Gu Jianyou, 1990). Later in 1946, a large number of lemon scented gums were introduced in Lingshan County, Guangxi Region from Hong Kong and planted in the county capital and along road sides as ornamental trees. At the same time, 1 ha of red bloodwood (E. gummifera) plantation was established and is conserved today (Gu Jianyou, 1990). Eucalypts were planted in Sichuan (Introduction Team of Research Institute of Forestry of Sichuan Province, 1987); Fujian (Chen Cunji et al., 1985); Guangdong and some other Provinces also (Qi Shuxiong, 1989).

Large scale establishment of Eucalyptus plantations came after the foundation of the People’s Republic of China. In 1954, a large area of eucalypt forest was set up in Leizhou Peninsula, Guangdong Province (Wu Zhongheng et al., 1990). In Guangxi Region, the Shankou State Forest Farm was established to manage lemon scented gum predominantly, and by 1970 had expanded eucalypt plantations to 40,000 ha. To meet demand for railway sleepers, a large number of eucalypt plantations were established in the 1960’s in southern, south eastern and south central China. In this period, more than ten forest farms were set up to manage eucalypts in Guangxi Region. This was the primary high tide of afforestation of eucalypts for timber production.

Eucalypts are also used for the establishment of protection forests, and its importance was early recognized. In the 1950’s, eucalypt protection forest with Acacia confusa and Casuarina equisetifolia were commonly established in Leizhou Peninsula. Under a 12 degree typhoon, the proportion of breaking and lodging of rubber trees was only 14.8% with shelter belt on four sides, compared to 44.8% with the protection of only one side shelter belt (West Guang-dong Reclamation Area Bureau, 1990).

Generally speaking in terms of production, the early work and study of Eucalyptus plantations has limits. It is pleasing to note that a great deal of research has been carried out since 1980, and China’s eucalypt plantations have reached a remarkable scale. This is a result of the hard work of the country's foresters, especially in developing early practices.

PRESENT SITUATION OF EUCALYPTUS PLANTATIONS IN CHINA

China is notable for its vast land territory, varied climates and geographical conditions which provides a broad background for the growth of tree species. Tests show that eucalypts can survive in many regions, ranging from latitude 18^o20' to 33^o10'N, and also from 4.5m (Shanghai) to 1,200m (Yun-Gui Plateau) above sea level (Ouyang Quan, 1990). Figure 2 shows eucalypts planted in different regions of China (Bai Jiayu, 1988). To date, there are 460,000 ha of man-made forests of Eucalyptus and 1.5 billion trees planted around villages and houses, along road sides and canals. The forests are spread through Guangdong, Hainan, Yunnan, and Fujian Provinces and Guangxi Region.

Figure 2. Eucalypts planted in different regions in China

In Guangdong and Hainan, there are 400,000 ha of eucalypt plantations, with E. exserta, E. citriodora, E. Leizhou No.1, and E. ABL No.12 as the major afforesting species (Wu Kunming et al., 1992). In recent years, E. urophylla has shown the fastest growth and highest yield and has a notable potential in practical wood production. In Hainan Island, eucalypt plantations cover 100,000 ha of land, 80% of which is for timber and the remaining proportion is for typhoon shelter belts. Eight species are primarily used, with E. exserta accounting for 97%. Recent experiments indicate that E. ABL No.12 is worth expanding on account of its excellent performance (Wu Guangru et al., 1988). A barrier to eucalypt plantations in Hainan is the low productivity. The mean productivity over large areas is 8 m³/ha/yr, and that of the best performance is 24 m³/ha/yr only (Li Weichao, 1983). Effective measures are urgently needed to improve the plantation productivity.

In Guangxi Region, there are 100,000 ha of Eucalyptus plantations. The main species are E. exserta, E. citriodora, and E. urophylla (Li Youpu, 1990).

In Sichuan Province, eucalypts are commonly planted around villages and houses, along road sides and canals. Investigations concluded that there were 0.5 billion individual trees; the main species are E. botryoides, E. robusta, E. camaldulensis, etc. (Bai Jiayu, 1988).

In Yunnan Province, three sub-species of E. globulus have been widely used as ornamental trees. Recently, a large area of plantations has been formed. Shanghai is the north east edge for eucalypts to survive in China, with the evaluation 4.5 m above sea level, the latitude 30^o10'N and the longitude 121^o26'. The main species are cold tolerant, as E. gunnii and E. cinerea (Bai Jiayu, 1988).

Apart from the above, eucalypt plantations in Hubei (Wu Shanjiu et al., 1990); Hunan (Hunan Eucalyptus Coordination Group, 1986); Guizhou (Eucalyptus Team of Research Institute of Forestry of Guizhou Province, 1986); Jiangxi (Huang Xiaochun, 1992), and some other Provinces have expanded on some scale.

Seedlings are largely used in most afforestation. Cuttings and tissue culture plants are beginning to take an important role in the process of eucalypt plantations (Peng Haizhong, 1983). Chinese foresters generally think that clonal forestry holds bright prospects in the advancement of eucalypts (Huang Rongcong, 1991; Wang Mingxiu, 1991).

Tree breeding and management measures are considered to be two important points to solve the problem of low yield that universally exists in China. A large number of suitable species, provenances and families have been selected. Several hybrid species show promise, such as E. saligna x E. exserta; E. Leizhou No.1 x E. exserta (Pan Yongyan, 1985). A series of effective management measures have been summarized and they have made a considerable contribution to the development of eucalypt plantations.

Different end use require specific eucalypt plantation management methods. Stand densities in timber plantations are in a range of 1,600-2,250/ha with spacing 3m x 2m in machine working sites and 2m x 2m at non-mechanised sites. The first thinning occurs one year after canopy closure, varying with the growth of trees. A suitable first thinning period is 4-6 years later when significant differences of growth are shown in the plantation (Zheng Haishui et al., 1990). In recent years, final cutting in pulpwood plantations is at 6 years.

China’s protection forests are mainly distributed over its southern coastal and south western mountain regions. In southern China, the shelter belt is to prevent injury by typhoon and cold weather. In the southwest, the main functions are to protect river embankments, fix sand and conserve water and soil (Qi Shuxiong, 1989). The principal species is E. exserta.

Eucalypt plantations are a good source of energy. In energy plantations, the spacing can be less than for timber plantations, and wood production (= yeild) becomes usually much higher (Zheng Haishui et al., 1990, 1991, 1992). In Guangdong Province and Guangxi Region, the average biomass of eucalypt fuelwood plantations ranges from 19 to 35 ton/ha/yr, with the top record of 79 ton/ha/yr, which is fur superior to any other tree species.

Mychorhiza inoculation promotes growth in eucalypt plantation. Studies indicate that the volume growth of one year old eucalypt inoculated with Pisolithus tinctorius increases by 5.12 m³/ha, accounting for 39.9% up; the mean height and diameter at breast height (DBH) increase by 14.3% and 13.7% respectively (Gong Mingqing et al., 1990).

Green manure plants have been commonly inter-cropped in many eucalypt plantations to improve soil fertility; most of these are species of the bean family, such as Tephrosia candida, Crolataria mucronata, Lespedeza bicolor, etc. (Wang Jingchang, 1985). Beneficial results have been achieved with a combination of soil fertilizers and green manure inter-cropping.

The general management measures for eucalypt plantations in China may be summarised as follows (Quli State Forest Farm, 1990):

• To apply suitable establishment and fertilization patterns to the soil;

• To use superior species, and breed superior seedlings;

• To plough in overall site preparation by tractor, and adopt timely planting practices;

• To plant green manure species to fertilize and improve the soil;

• To plant seedlings in an appropriate density, and practice thinning on determined schedules;

• To tend trees and maintain stands healthy to prevent pests and diseases problems; and

• To manage stands scientifically to promote economic benefits.

ECOLOGICAL ASPECTS

Different opinions exist on the relation between eucalypt plantations and its negative impacts on ecosystems and environment. The dispute focuses on three points: soil degradation, the water cycle and biodiversity. The practice of establishing large scale eucalypt plantations in China has proven that positive effects can be produced on the environment.

Protection function

In southern China, eucalypts have been widely employed as protection forests along coasts and river banks, and around crop lands. Survey data indicates that eucalypt shelter along the coast decreases the typhoon damages by 50-80% (West Guangdong Reclamation Area Bureau, 1992). Another example is shown in the 84 km long shelter belt along the Nanliu River in Guangxi Region. This shelter belt, which was established in 1974, now effectively provides the safety of 92,000 people and protects 8,000 ha of crop land (Ouyang Quan, 1990). In Hainan Island, the eucalypt protection forests standing around rubber plantations can increase the productivity of latex by 10% (Wen Maoyuan, 1982).

Functions in soil and water conservation

Eucalypt plantations have made great contributions to soil and water conservation. Data from Jingdong County, Yunnan Province, shows that after the establishment of eucalypt plantations, the density of soil decreases by 6%, and 98% of the stem run-off, and 99% of the mud and sand movement are intercepted.

Effect on the water cycle

Eucalypts, as fast growing species, have a high rate of water metabolism. It can survive in some dry sites because its exploring tap roots reach deep in the earth to absorb water and overcome the lack of water supply in the surface soil. On the other hand, its transpiration is not so intensive. Data shows that water consumed by E. hybrid to produce 1 gram of dry matter is 0.48 litre (l), much less than that of Acacia lebbeck (0.55 l) and Dalbergia sissoo (0.77 l) (Zeng Lingying, 1988). Though eucalypt consumes a certain quantity of water to support fast growth, eucalypt plantations do not worsen the water conditions in forest soils.

Effect on soil fertility

Eucalypts absorb a large amount of nutrients to maintain fast growth. However, through photosynthesis, the tree also produces nutrients. Much of the nutrients that are absorbed from the soil and produced in leaves can return back to the soil via dead leaves and branches. A steady nutritional balance can be kept under correct management.

Recent opinions conclude that eucalypts could lead to the decline of soil fertility, as the forest land quality in eucalypt plantation declines. There are defects in this. First of all, soil decline does not occur in eucalypt plantation only. It was reported that Michelia macclurei and Erythrophleum fordii, which are thought to be good in conserving soil and water, also led to soil decline. Secondly, there are some successes reported in improving soil fertility of eucalypt plantations. In Dongmen State Forest Farm, Guangxi Region, dead leaves and branches are retained in eucalypt forest, and the occurrence of soil decline is avoided. The investigation of 16 year old eucalypt plantations suggests that the organic matter content in the soil increases to between 1.78% and 3.25%, which is much higher than the content between 1.2% and 2.5% 16 years ago; the variety of vegetation and species of bird, animal and insect life also increases (Zhao Tingxiang et al., 1990). In fact, in nearly all the plantations where soil decline takes place, the dead leaves and branches have been removed as fuel materials by residents, greatly reducing soil fertility. Thirdly, the loss of nutrients can be compensated to soil with fertilization (Lin Shurong et al., 1992). Thus, soil decline is not due to the eucalypt itself, and can be avoided with effective management measures.

Developing biodiversity and keeping ecological balance

In southern China, Eucalyptus trees grow on what was barren land. With the establishment of eucalypt plantations, the ecological conditions distinctly improve and the number of life forms rise. In an area of 100 m², more than 20 species of plants were found. With the increase of bird life, bird excrement can be seen everywhere in some plantations. It was reported that 23 classes, 71 bird species, live in eucalypt plantations of Guiqi County, Jiangxi Province, more than that in Pinus massoniana plantations (Zhu Miaochang, 1990).

Inter-cropping is feasible and also has many advantages in establishing eucalypt plantations, e.g. improvement of soil fertility, cure and control of insect and pests, water and soil conservation, etc. (Zhao Tingxiang et al., 1990).

The conclusion is that the establishment of eucalypt plantation under reasonable and responsible management does not stand a ghost of a chance of worsening the environment. We strongly support the concept of the development of China’s eucalypt plantation.

ECONOMIC AND SOCIAL ASPECTS

The introduction of Eucalyptus has contributed much to China’s economic and social progress. It contributes to improving ecological conditions in one hand, and to raising the living standard of people, introducing new technology and producing new forestry organizations (Bai Jiayu et al., 1990).

Eucalyptus is one of the important national resources of commercial timber. Its annual production reaches to 5 million m³/yr (Qi Shuxiong, 1989). In southern China, eucalypt wood is largely used for producing chips for paper making and for man-made fibre industries. From April 1989 to March 1990, 171,000m³ of eucalypt chips were exported to Oji Paper Cooperation in Japan (Yoshimasa, 1990). In rural areas, eucalypt timber is generally used for making doors, window frames, floors, farm implements, etc.

Eucalypts, as fuelwood species, have a high combustion value. In the south, eucalypt fuelwood plantations have solved the fuel shortage problem. In Yunnan Province, 5.5 year old regenerated forest of E. maidenii under coppice management can produce air seasoned fuelwood of 118 ton/ha (Qi Shuxiong, 1989).

Eucalypt oil is a by-product. China annually produces more than 2,000 ton of eucalypt oil. The income of this essential oil takes 20% of the total earning of foreign exchange which is generated from eucalypt products (Song Yongfang, 1990). Also, eucalypts have an important application in the production of honey. Many hives are placed in eucalypt plantations in the flowering season. Intercrops with eucalypts provide short term economic benefits. In a town of Hainan Province, sweet potato was inter-cropped in 208.7 ha of eucalypt plantations in 1984, and brought an income of 1,286 RMB/ha. This income exceeded the total annual investment of afforestation (Zeng Qingbo, 1992). Today eucalypts are essential for peasants to become rich and, the country to earn foreign exchange.

Along with the development of Eucalyptus plantations in China, new organizations for afforestation have appeared. Individuals, forestry colleges, research institutes, local governments, or unions of two or more departments, can become plantation managers. Eucalypt chip processing factories on varying scales have been established. In addition, the number of commercial traders in eucalypt timber is increasing.

GOVERNMENT POLICIES, PROGRAMMES ON EUCALYPTUS PLANTATIONS

Since the founding of the People’s Republic of China, the Government has adopted a series of policies to develop forest plantations. In a long term view the policies emphasised the reforesting of barren mountains with extensive plantations. Current emphasis lies on establishing short term plantations under intensive management methods. Eucalypts play an increasingly important share in the afforestation of the southern territory. Advantageous measures have encouraged Departments at each level to manage eucalypt plantations, to stimulate export trade, to set up eucalypt chip production factories and to establish eucalypt pulp factories, etc.

Schedules have been developed to expand eucalypt plantations in each province. Strategies being formulated in Guangdong are to establish 400,000 ha of eucalypt plantations, in which the higher yield of wood, ranging from 12 to 15 m³/ha/yr, is aimed. The corresponding guarantee for success is reliance on scientific afforestation research and intensive management.

The current programmes for eucalypt plantation development in the south include:

1. A national afforestation project (World Bank loan). Target (60,000 ha;

2. The high-yielding project in Hainan Province. Target (130,000 ha;

3. Guangdong eucalypt engineering. Target (200,000 ha;

4. Forest pulp and paper project, Shanwei City, Guangdong Province, managed by Thailand. Target (30,000 ha;

5. The Eucalypt Development Plan in Guangxi Province;

6. The Developmental Strategy for Eucalypts in Hainan Province; and

7. The Developmental Strategy for Eucalypts in Yunnan Province.

The foundation research programmes on eucalypt plantations include:

1. The Australia-China Demonstration Plantation Project, Dongmen State Forest Farm (1984-1990);

2. Introduction and cultivation experiments of Australian broad-leaved tree species, Chinese Academy of Forestry and ACIAR (1985-1992);

3. Research by China Eucalyptus Research Center, Forestry Ministry of China;

4. The demonstration of classified management and sustainable utilization of tropical forests in Hainan Island, aided by ITTO (1993-1997); and

5. Some key projects on eucalypts in the Eighth Five year Plan (1991-1995).

We acknowledge with thanks the valuable contributions made to China’s eucalypt plantations by international organizations and foresters, especially those of Australia. We believe that, with the help of international forest departments, institutes and individuals, and through the great efforts of Chinese foresters, magnificent progress will be made to develop eucalypt plantation in China, and it will further enrich the Chinese society. Also, eucalypt plantations will have a highly positive effect on world forestry and other aspects.

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