2.1 Macro-level Land Resource Utilization

The Lao People's Democratic Republic (Lao P.D.R. or Laos in short) is a small land-locked country with an area of about 23,680,000 ha, of which 89% is mountainous. Lao P.D.R. has been rich in natural resources, especially forests and water resources. However, the decreasing forest areas from 74% in 1973 to 47% in 1981 affects the environmental and socio-economic setting of the country. Forest destruction often induces soil degradation and flash floods due to the agricultural practices particularly that of shifting cultivation in steep slopes.

The population density of Lao P.D.R. is lowest compared to other countries in Southeast Asia. A mid-1990 estimation indicated a population of 4,170,000 persons with a population density of 18 persons per sq. km. More than 60% of the people live in the valleys of the Mekong river and its tributaries, concentrated in the riverine provinces of Vientianne, Savannakhet, Champasak, Luang Prabang and Khammouane. Elsewhere, the population is thinly spread, particularly in the mountains. Eighty-five percent of the population is classified as rural and there is no significant urban-rural migration (UNDP,1991).

The large proportion of the population is not yet consumer-oriented, has low energy consumption, practice small scale industrialization and adopt subsistence pattern of farming. However, since subsistence agriculture has low productivity, there has been an inevitable tendency to increase the amount of land being farmed by using marginal areas of forests.

Deforestation in this country is mainly caused by man made activities such as shifting cultivation, uncontrolled burning, and improper forest management practices. In the northern region, where the road network is poor with broken terrain, logging activities are much less than in other parts of the country, but shifting cultivation remains the main cause of deforestation.

Like many other Asian countries, shifting cultivation plays a vital role in accelerating the deforestation processes in Lao P.D.R. The traditional slash and burn practices was fairly stable with basically long fallow periods. However, increasing population tends to shorten rotational cycles. Moreover, high steep mountains in northern Laos are characterized by shallow soils marked by low fertility. This low production per unit area in the mountains encourages people to expand their shifting cultivation areas beyond their traditional territory. On the other hand, lowland farmers because of insufficient areas for lowland cultivation, encroach into neighboring hills that are primarily forests. These land use practices are the major causes of deforestation and degradation of forest land in Laos. Fire is the most commonly used land clearing practice that also contributes substantially to the degradation of forests (Ministry of Agriculture and Forestry, Lao P.D.R., 1990).

2.2 The Nature and Problem of Shifting Cultivation

Shifting cultivation was a legitimate and rational form of land use in Laos at a time when population was small and forest cover was much more extensive. This type of agricultural system in the country is consisted of the clearing and cultivation of a new piece of land for 2 to 3 years followed by a fallow period of 10 to 12 years. Complete clearing of all vegetation was rarely done and during the fallow period a secondary vegetation cover developed, soil fertility was restored and soil loss through erosion was limited. This is a very old practice that is still going on in Laos. Every year the villagers needs to clear forest to grow food crops for their livelihood.

However, it is now widely accepted that shifting cultivation in many parts of the country particularly in the northern provinces possesses a serious impediment to rational forest management and sustainable use of soil and water resources (Phangthalangsy, 1991). Mainly due to the rising population, a more destructive slash and burn system is now being practiced in the uplands, the fallow period being shortened to about four years. Moreover, the lower foothills are increasingly being encroached upon by lowland farmers for cash crop production. Methods of cultivation are aimed at the highest possible immediate production, and not at conservation and stability (IUCN, 1988).

Forest clearing is done usually by burning. The rich organic matter in the topsoil is readily available to the crops in the first cropping year. The crop can take up a fraction of these nutrients, and much will be lost through leaching. This is primarily because most upland soils in the humid tropics have low nutrient storage capacity and the organic matter is the most important medium in which nutrients are accumulated. Unfortunately, shifting cultivators changed their farming practices to such an extent that the sustainability of the system is jeopardized. This may occur through shortening of the fallow period and insufficient compensation of nutrients loss due to over-exploitation and insufficient erosion control measures. In the absence of proper management of soil organic matter, the topsoil will be exhausted in 1-3 years, thus preventing further agricultural use.

Forest fire is a common phenomenon in Laos, every year. The elevated and steeply sloping swiddens are reburnt year after year, and no trees are left standing (Keen, 1983 as cited by IUCN, 1988). Fires are not carefully controlled, and frequently get out of hand. Destructive consequences of the felling of trees through slash and burn practices and forest fires alter the environment and nature. The forests were extensively destroyed, droughts and soil erosion consequently follow.

The impact of shifting cultivation on forest resources takes different forms in different regions of the country. In the uplands, short cycles of shifting cultivation lead to the forest being replaced by grasslands and scrub lands dominated by bamboo. These upland forests have important watershed values and are valuable habitat for wild flora and fauna. Forests at lower elevation, particularly along the edge of the Mekong plains, have similar environmental values to the upland forest, but are also important sources of timber both for national use and for export. These forests are subject to the dual threat of logging and shifting cultivation.

At present, about 300,000 ha (of which about 100,000 ha is covered by secondary vegetation) of the total 11.2 million ha of forest land is affected by shifting cultivation. The total number of shifting cultivators are estimated at about 253,000 families. In the north, about 70% of the population that accounts 177,100 families, practice shifting cultivation. The number of shifting cultivating families in the central region is approximately 40,000 over an area of about 60,000 ha. In the south there are large plains, the Boleven plateau and steep mountains along the borders of Vietnam and Cambodia. Here, only 36,000 families practice shifting cultivation. The total area under shifting cultivation in the south is 25,000 ha (Phanvilay, 1990). Information on the extent of shifting cultivation however, is unreliable, both with respect to the areas subject to this practice, the methods employed and the impact on forests.

Various types of swidden agriculture are being practiced by the different ethnic groups in both upland and lowland areas. These practices are generally leading to a decline in the areas under productive forest, under protection forest in the watersheds, and decline in habitat for wildlife and in the productivity of the land for agriculture.

2.3 Micro-level Land Resource Utilization in Oudomxay Province

The apparent "hot spots" area where the major land cover transformation has been observed using the multi-temporal AVHRR data was identified within the large extent of the forested domain of Oudomxay province, north Lao P.D.R.. A comparison between the 1985-1986 and 1992-1993 AVHRR data covering the country shows a distinct variation in the spectral signature and NDVI value of that region. The transformation of open or dense deciduous forests into more open type such as scrub land or "unstocked forest area" signifies human activity. The proliferation of shifting cultivation was observed particularly along the watershed tributaries. The chosen study area covers an estimated area about 36,000 sq. km. with an approximate geographical location of 101⁰ 4^' 15^'' to 101⁰ 56^' 10^'' east longitude and from 20⁰12^' 38^'' to 20⁰ 48^' 47^'' north latitude. The selected area will serve as a representative plot for in-depth study regarding on-going deforestation phenomenon in this northern part of the country.

 2.4 Oudomxay Province: Location and Physical Characteristics

The study area encompasses considerable portion of the Oudomxay province in the forested region of the province. It lies more or less at the center of the provincial domain that is about 50-km south-west of the main district of Xai (see Fig. 2.1). For the purpose of the present discussion, most of the secondary data pertaining to this province were synonymously used to discuss several facets of the chosen study area.

Large portion of the study area is mountainous and drained by two river systems, Nam Beng and Nam Tha. The greater part of the highland consists of an extensive rugged mountainous area in which the main ranges run northeast to southwest. The mountains are dissected with steep slopes and narrow valleys.

Nam Beng river basin covers large area of this study area and located on the left bank of the Mekong river. Nam Beng, 120 km long, rejoins the Mekong at the village of Pak Beng. Likewise, Nam Tha catchment area also offers almost no lowland for agriculture in the lower part of the basin is populated by ethnic minorities. Major infrastructure noticeable within the chosen study area is Road No.2. This road connects Oudomxay and Pak Beng and runs along the Nam Beng River. Its construction somewhere in 1970's has resulted in many new permanent settlers. Transportation of goods from Thailand to China via the Pak Beng river port and along Road No. 2 has increased its importance.

Initial observations using SPOT imagery taken on 26 March 1992 (Fig. 2.2) exhibited a conspicuous sporadic patches of slash and burn agricultural practices in the mountain that separates the Nam Beng and Nam Tha valleys. They resemble various levels of shifting cultivation practices from cleared or burnt field into long and abandoned fallow fields. Homogenous and large abandoned shifting cultivation associated with bamboo and medium-sized trees dominates the western side of Nam Tha watershed while dense forest still covers the eastern side of Nam Beng watershed where high peaks and steep slopes are prominent. The land along the narrow valleys within the major river system utilizes for rice cultivation.