Forestry Officer, Afforestation Department, State Forestry Administration, Beijing, Peoples Republic of China
Approximately 3.67 million square kilometers, or some 38.3 percent of the total land area of China, are seriously eroded. Soil erosion is increasing at a rate of 10 thousand square kilometers per year. The desert soil areas of China cover 2.62 million square kilometers, accounting for 27.3 percent of total land area. Deserts are expanding at an annual rate of 2 460 square kilometers. Since the 1990s, sand storms have occurred more frequently during the spring season, especially in northern China. In brief, environmental degradation is a serious problem demanding immediate and urgent attention to hasten the process of land greening with trees and grasses. Assisted natural regeneration (ANR) can play an important role in this process.
In China, ANR can be divided into two main categories: special ANR and general ANR. Special ANR is practiced on cutover land with natural sowing capacity, but lacking some of the essential requirements for natural regeneration. Artificial assistance measures such as soil preparation are conducted to improve site conditions for forest establishment. General ANR refers to regeneration and afforestation accompanied by artificial sowing, tending and other treatments. It is conducted on barren hills, waste lands, barren desert lands, cutover lands, river banks with important ecological status, sandy regions damaged by wind and so on. The objective is the establishment of vegetative cover to protect the land. In regions where some natural sowing occurs, hillsides are closed to most forms of exploitation for a number of years (depending on local conditions). Use of the land is restricted or prohibited during the closure period in order to facilitate forest establishment from natural seed fall. In regions where natural sowing and natural regeneration are difficult, the practice of closing hillsides is combined with aerial sowing of tree and/or grass seeds.
Hillside closure is a system that includes both administrative and management measures. Three types of hillside closure are distinguished in China:
(1) Full-closure is adopted for a period of three to five years or eight to ten years (depending on local conditions) in regions such as remote mountains, upper reaches of rivers, water catchments of reservoirs, sites characterized by severe soil erosion, desert soil areas subject to wind damage and other regions where natural regeneration is difficult.
(2) Semi-closure is practiced in areas where some target tree species are growing well and where the percentage of forest cover is relatively high. Under semi-closure, strict protection is prescribed to protect the saplings and seedlings of target tree species. However, controlled cutting of firewood and grass may be allowed.
(3) Full-closure and semi-closure are combined in regions where farmers are very poor and firewood is scarce. Full closure periods alternate with semi-closure periods. There are no fixed standards. The lengths of full or semi-closure are variable depending on the progress achieved in restoring vegetative cover.
Forest cultivation refers to the implementation of measures that promote forest establishment. Soil cultivation and other management activities are carried out to improve conditions for tree growth and to harness the natural reproductive capability of trees or grasses. Concurrently, silvicultural treatments are applied to enhance forest quality such as replanting, reseeding, tending and so on.
Aerial sowing is combined with hillside closure. Airplanes are used to spread tree or grass seeds under suitable conditions. The sites selected for aerial seeding include the types of land mentioned above, where the chances of successful regeneration with minimal human assistance are high. Under favorable conditions, the seeds germinate, grow, and eventually mature into a forest.
As of 2001, over 30 million hectares of forest had been established through the hillside closure system. Aerial sowing of tree or grass seeds had been implemented in 931 counties of 26 provinces (autonomous regions and municipalities directly under the Central Government). Approximately 8.68 million hectares of forests had been established via aerial seeding, combined with hillside closure. This accounts for 25 percent of the total artificial forests of China. ANR has played a very important role in expanding forest resources, controlling soil erosion, retarding the process of desertification, improving the ecological environment and improving the living conditions of farmers.
There are five principal constraints that have impeded expansion of ANR practices in China:
1. Most of the forests established through hillside closure, or aerial sowing combined with hillside closure, are shelter forests. As such, they have relatively low economic value. Given the meager benefits, many farmers are not willing to practice hillside closure.
2. Previous levels of investment in these regeneration patterns were insufficient and the implementation time frame was not long enough to ensure success. Prior to 2000, the investment in hillside closure was only 3.0-7.5 yuan RMB (US$0.35-0.90) per hectare. The amount allocated for aerial sowing combined with hillside closure was only 150 yuan RMB (US$18) per hectare.
3. There are no quantitative technical systems to evaluate the standards of established forest, nor the ecological and economical benefits of these regeneration practices. Consequently, the practices are often perceived as extensive in area, but low in terms of effective forest establishment.
4. In forests established by aerial sowing combined with hillside closure, the density is too high and the quality of these forests is relatively poor. This is due to a lack of appropriate tending and insufficient financial resources to invest in tending.
5. The land types selected for aerial sowing are located in areas that are difficult to afforest due to poor site conditions. There is a need for improved and more advanced techniques. Many techniques have been tried, but few have proven useful or effective to date.
Promoting ANR practices in China
Fortunately, since 1999, the Government has taken new initiatives to accelerate the process of afforestation and improve ecological conditions. First of all, six principal forest ecology programs have been launched covering more than 97 percent of all counties in China. The scale of investment is unprecedented in the history of the country. The goal is equally impressive. Sixty million hectares are targeted for afforestation. Secondly, 685 counties and 24 State Nature Reserves in 11 provinces have been selected for implementation of pilot projects, where the development of eco-forests will be subsidized. The pilot projects cover 13.33 million hectares of shelter forests and special forests.
Under these programmes, the investment and scale of ANR-related initiatives have increased significantly. Based on the overall plan of key forestry ecological programs, hillside closure will be practiced on 13.35 million hectares from 2001 to 2010. Levels of investment will increase from the former 3 to 7.5 yuan RMB per hectare to 1 050 yuan RMB (US$128) per hectare. Total investments in these regeneration practices will reach 14 billion yuan RMB (US$1.7 billion) in the next 10 years.
Aerial sowing of tree seeds combined with hillside closure will be launched on 10.89 million hectares. Budgets for this method of forest regeneration will be increased from 150 yuan RMB per hectare to 1 800 yuan RMB (US$220) per hectare. In the next ten years, 19 billion yuan RMB (US$2.3 billion) will be invested in aerial sowing combined with hillside closure.
Given the increased levels of investment and the new programs, one can anticipate that ANR will henceforth play a more important role in the process of afforestation and improvement of environmental conditions in China.