laos result by M2I00Q3C


									2. Case Study 1: Oudomxay Province, Lao P.D.R.

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

         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.

Fig. 2.1

        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

          Figure 2.2. SPOT XS satellite image of the study area (26 March 1992)

2.5 Socio-economic Characteristics

         Oudomxay province had a population of about 291,000 persons in 1990 (Mekong
Secretariat, 1993). Three major ethnic groups and 26 tribes comprise the population of the
province. The largest ethnic group is the Lao Theung, constituting about 55% of the
provincial population, while the Lao Lum and Lao Sung represent 31% and 13%,
respectively. The majority of the Lao Theung live in Xay, Houn, Beng and Pak Oudom
districts. The Lao Lum live in smaller towns and in valleys, while the Lao Sung are
dispersed in Xay, Nga, Houn and Pak Beng districts. There are 261 number of villages being
identified in 1983, 1:100,000 topographic map within the chosen study area. Out of this, 181
villages were considered as large villages and the remaining 59 and 21 villages were
accounted as small and abandoned categories, respectively. The main occupations of the
population are farming and livestock raising. Slash and burn cultivation remains the pre-
dominant agricultural practice in the study area.

        Comparative result among the northern provinces of Laos, shows that Oudomxay
exhibits the highest population growth of 55% from 1985 to 1990. Local forestry official
ascertained that migration from the nearby provinces (e.g. Luang Prabang and Phongsaly)
intensifies the provincial population increase. Additional data appeared in Table 2.1
manifests that Oudomxay province covered one of the highest hectarage subjected to slash
and burn practice in northern provinces of this country.

2.6 Land Utilization Practice

         According to the data available from the Provincial Agriculture and Forestry Office
of Oudomxay, forest area covers 420,500 ha. of the province. The "forest" has been further
classified into four categories viz. preserved forest (230,400 ha), improved forest (66,200
ha), production forest (81,200 ha) and unclassified forest (42,700 ha). Approximately,
30,000 ha of forest land is used every year for upland crop production, with an annual
average rice crop production of 50000 tons (Mekong Secretariat, 1993). Hence, the province
of Oudomxay is nearly self sufficient in rice production. However, due to the limited
availability of both low and irrigated lands, slash and burn cultivation is the predominant
agricultural practice in Oudomxay province.

        In the upland system the main food crop, rice is cultivated for one year, then the land
is abandoned to 3 to 4 years fallow. In isolated villages where the pressure of the population
is low, the fallow may last 5 to 20 years. Maize, legumes and potato normally follow a
similar cycle.

        Land clearing starts in January-February by slashing of the under-brush and the
higher trees. About six weeks later the dried material is burnt, during which special care is
taken to prevent the spread of fire into the adjacent forest. Although upland rice in general is
the main crop, other crops such as cassava, maize and chilli are also part of the cropping
patterns. Crop calender of upland farmers starts one or two months in advance than that of
the lowland farmers.

Table 2.1. Population and Forest Data of Selected Northern Provinces in Lao P.D.R.

Northern       1985            1990                 % Population    1981 Forest 1981 Slash
Province       Population*     Population* *        Increase        Area*       and Burn
                                                    (1985-1990)                 Area*
Oudomxay       187051          291000               55.6            230000          40370
Luang          295475          339000               14.7            187000          56000
Luang          97028           114000               17.5            441900          17800
Phongsaly      122984          142000               15.5            480000          21380

Source: * - Phanvilay (1990)
      ** - Ministry of Economy Planning and Finance (1990)

        Old shifting cultivators keep on rotating the same field according to the prescribed
fallow period. However, new cultivators normally migrate from adjacent villages to create
new opening in the forest. On the other hand, if the clearing is already too far from their
original village a new small village will be established. One family with five members
normally holds at least five hectares of plot.

         Solicited field information indicated that upland cultivators preferred to open new
forest than to cultivate long time abandoned fallow fields despite of the enormous task entail
in removing tall and big trees. The possibility of obtaining large amount of ashes after
burning together with stored organic matter within the forest soil became the major reason
for them to prefer this site for their clearing practice. Besides, the availability of small to
medium sized logs and abundance of firewood from a newly cleared forest were considered
useful for housing construction or supplemental goods to be sold within the community.

2.7       Land Use/Land Cover Mapping Using Remote Sensing and GIS

2.7.1 Datasets and Methodology Used

        SPOT multispectral satellite data acquired on March 26, 1992 was used as the
principal source of information for the present study. Topographic maps and published
information about the land use/land cover practices in the Northern Laos were also utilized.
An intensive field trip of four days was organized on December, 1994 approximately three
months earlier than the month of the acquisition of the satellite data. During the field trip,
informal interviews were taken with the government staff and local people. A part of the
study area was visited by establishing number of sample plots. In each sample plot
information regarding shifting cultivation, forest types, topography, slope etc. were noted.

       The SPOT image was spatially georeferenced to a UTM map projection using a first
order polynomial and resampled with nearest neighbor algorithm. For the selection of
ground control points (GCP), 1:50,000 topographic maps were utilized. A RMS (Root
Mean Square) error of ± 1 pixel (±20 m) was accepted during the rectification.

        Supervised classification using maximum likelihood classifier in ERDAS ( an image
processing software) was performed by selecting number of training samples. Statistical
analysis for these training areas were performed to find out their consistency. The classified
image was converted to vector format for further GIS analysis in the ARC/INFO

         Village map was digitized from the 1:100,000 scale topographic map. Other
information layers available in digital format were used in the study include, rivers, road
networks, elevation and geology. These information were extracted primarily from the
Digital Chart of the World (DCW) and were used for various GIS analysis with the
classified image. The flow-chart of the methodology is shown in the figure below.

                                                                     Topographic Map
               SPOT XS

                                                                            Field Data
                                           Training Area

                                     Maximum Likelihood

                                          Land Cover
         GIS Data Base
         . Village map
         . Road map
                                     Map Integration
         . Elevation map
         . Geologic map

               Figure 2.3. Methodological flow chart for hot spots land cover analysis.
2.7.2 Land Use/Land Cover Categorization

       Digital interpretation of the SPOT multi-spectral satellite data yielded eight major
land use/land cover types for the study area. Forest category has been subdivided into three

levels from its dense to a more open formation as affected by shifting cultivation. Likewise,
varying stages of the shifting cultivation area were discerned from the newly cleared plot to
that of abandoned shifting cultivated areas. Since majority of the study area consists of
rugged mountains, along its narrow valleys lie paddy fields and on steep slopes topographic
shadows abound. The following land use/land cover categories were discerned.

       (Fc)    Dense forest dominated by evergreen type

       (Fd)    Degraded forest either evergreen or semi-evergreen formation, and open

       (Fb)    Scrubland composed of mosaic of open secondary growth with shifting
               cultivation and long time abandoned shifting cultivation area covered with
               bamboo and patches of trees

       (Sc11) Burnt shifting cultivation

       (Sc1) Newly cultivated shifting cultivation where soil is exposed

       (Sc2) Early stages of shifting cultivation fallow period of not more than 4 or 5
             years, covered by agricultural debris, grasses, and bushes

       (Sc3) Shifting cultivation undergoing long fallow period(around 5-10 years),
             covered by thick bushes with small patches of small to medium sized trees.

       (Pdy) Permanent agriculture, includes both rain-fed and irrigated rice fields

       (Wtr) Water bodies as represented by river and shallow water along the valleys

       (Ndt) No data available, mountain shadow and haze.

        Mean value of representative training samples illustrates their varying vegetative
intensity as demonstrated by the computed NDVI (normalized difference vegetation index)
and the reflected infra-red channel (Band 3) of the satellite sensor. The weak NDVI values
of the burnt agricultural plots (-0.03) particularly in the upland compared to the strong
NDVI values of the close forest (0.3) were visibly shown in Figure 2.4. As part of upland
farmer's field preparation, the exposed soil exhibits the brightest spots in the imagery, where
a higher value of reflected visible light is also apparent.

                                             NDVI = (SNDVI/126) -1
Figure 2.4. Training sample mean pixel values of major land use/land cover categories.

        However, series of similarities among the identified land use/land cover types were
noted. This occurs between the lowland paddy field and the newly cultivated shifting
cultivation where soil is exposed or recently left after harvesting. During the month of
March, rice fields along the narrow valleys is still being left idle until the rain comes. In this
respect, dried rice straw combined with exposed soil become the dominant cover of this
paddy fields. Different forms of degraded forest and long time abandoned shifting
cultivation also show difficulty in properly demarcating their boundary both in the imagery
and on the ground. The effect of haze is also found visible for various stages of shifting
cultivation especially along the valleys of Nam Tha and Nam Beng.

2.7.3 Land Use/Land Cover Assessment

        The location as well as the size of shifting cultivation captured by the SPOT data
exhibit a striking phenomenon of the study area. Majority of these cultivated areas are
located just in between two major river systems. Large portion of abandoned and degraded
forests are located in the left side of Nam Tha while the eastern side of Nam Beng is
dominated by dense forest. In this regard, the proximity of these river systems where large
villages are located, provided a strong link in terms of trading of goods and services. The
presence of Road 2 along the Nam Beng river serves as the market pull in eastward direction
for the villagers residing near the road. At present, the prominent steep slopes on the eastern
side of Nam Beng yielded a natural barrier for the community not to expand this cultivation
on this pristine and well-covered forest area.

              Figure 2.5. Shifting cultivation practices along the sloping area.

        The more or less rolling and less steep topography in the lower part of the study area
approaching the Mekong River signifies larger plot size of upland cultivation compared to
small patches in the hilly and steep slopes in the north. Large plot measures 650 to 200 ha.,
while smaller plot averages 2 to 3 ha. Small patches of cultivation were reported to contain
5 to 8 families in isolated distribution while large size cultivation accommodate 60 to 100
families. On the other hand, size of paddy cultivation increases as the river meanders

        Large proportion of the forest cover especially in the eastern side of Nam Beng is
dominated with evergreen formation particularly the Dipterocarp group. The vast area in
between Nam Tha and Nam Beng valleys where topography is somewhat rolling, exhibits a
disturbed forest formation affected largely by shifting cultivation. The forest area in the
western part of Nam Tha was reported to be subjected to such agricultural practice in long
time ago. The presence of secondary forest with bamboo and tall grasses manifests the
decreasing impact of human activity. On the other hand, a wide distribution of recently
cultivated and abandoned shifting cultivation in the valleys of Nam Beng illustrate that the
present utilization and intensity of cultivation of land is focused and more pronounce on this

    Figure 2.6. Dense evergreen forest on steep slopes (east of Nam Beng).

Figure 2.7. Degraded form of forest as a result of shifting cultivation practices.

        The spatial distribution of ten land use/land cover categories based on the
interpretation of the SPOT satellite data was enumerated in Table 2.2. It shows that
approximately 32% of the chosen study area is considered to be covered by dense evergreen
dominated forest, while 42% of the total area are found subject to human exploitation under
different form of cultivation practices from lowland to upland. An estimated 20% was
attributed to the places blanketed by open woodlands or degraded type of forest (see Figure

Table 2.2. Areal extent of distribution of the classified land use/land cover categories
        (in hectare).
                  Land use/land cover Area (hectare)             %
                  Fc                         117398.1            32.61
                  Fd                         71298.8             19.81
                  Fb                         104345.0            28.99
                  Sc11                       5021.6              1.40
                  Sc1                        13161.2             3.66
                  Sc2                        9330.8              2.59
                  Sc3                        20551.8             5.71
                  Pdy                        921.2               0.26
                  Wtr                        285.5               0.08
                  Ndt                        17655.1             4.90

       Narrow valleys offer small area of about 921 ha primarily allotted to rice cultivation.
Hence, a total area of 48,000 ha has been presently utilized for upland cultivation at various
topographic gradient.

2.7.4 Map Integration through GIS

        Combined available ancillary data with the generated land use/land cover of the
study area using GIS render additional dimension in terms of analyzing the resource
variables on it. Relevant results on its spatial aspect have been highlighted below.

       Spatial interactions about the frequency and location of villages among the identified
land use/land cover types (1992 SPOT data) were established. The 1983, 1:100,000
topographic map of Lao P.D.R. provided the location and different categories of village
according to the number of houses such as big, small and abandoned villages. Villages
composed of 15 to 19 houses was classified as small village and more than 20 houses up to

Figure 2.8

155 falls under bigger division as indicated on the topographic map sheets covering the
whole study area. However, isolated villages with house composition of less than five were
not included in this investigation.

                     Figure 2.9. Paddy fields along the narrow valleys.

         Major findings indicated that large number of big villages are generally located on
classified scrubland (Fb), while 20% are positioned in shifting cultivated area. Only one big
village was found inside a burnt cultivation plot in the upland (Sc11). A different
observation was noted for small villages wherein they are largely situated in areas covered
by close forests. Neither of the 21 abandoned villages fall in any shifting cultivation area nor
paddy field.

        Likewise the proximity of the villages according to the existing land use/land cover
type that surround them was also analyzed. A 1 kilometer buffer for every village type was
demarcated purposely to identify the influence of their presence on the type of land use/land
cover within this range. In general, disregarding the village category, scrubland where trees
and bushes regarded as the dominant cover (Fb) followed by thick forest cover (Fc) tends to
be the common land use/land cover type within a distance of 1000 meter away from the
village. The nearness to the site where wood for much needed construction materials,
fuelwood and the water supply became the prominent reason for such kind of distribution
pattern. About 18% of the one kilometer buffered area is said to be covered by shifting
cultivation area. This also illustrates that upland cultivators normally travelled more than
one kilometer distance away from their houses in order to reach and search for their
respective agricultural plots.

                   Figure 2.10. Typical upland village and its surrounding.

        Considering the village category, large communities appeared to cover large area for
scrubland similar to abandoned villages. However, permanent form of cultivation such as
paddy area is obviously absent in a deserted community. The presence of plots where soil is
exposed or recently burnt spot shows that human activity is still going-on despite the
absence of their village within that area. Small group of houses requires both the ecological
and economic support from the forest, thus, maintaining their presence adjacent to a tree-
covered site. Their respective upland plots are somewhat located away from their houses
and one kilometer distance is not yet far for them to search and utilize a certain piece of land
on the hills and mountains. Table 2.3 provides the land use/land cover type distribution on a
kilometer radius from various village categories.

        Using an elevation map with 100 m contour interval, the study area was found lying
at a minimum of 800 m and reaching as high as 1100 m. The distribution of interpreted
forest types and various stages of shifting cultivation on changing elevation gradient
identified do not reveal any distinct spatial pattern. The decreasing human activity is
apparently related to the increasing elevation. Only a few patches of cultivation plots were
found situated in the range of 1000 - 1100 m. On the other hand, the presence of major
forest cover distributed at the middle elevation (800 - 1000 m) bears a strong threat towards
human exploitation where they share a common altitudinal preference. Table 2.4 enumerates
major land use/land cover types in various elevation categories.

Table 2.3. One kilometer radius distribution of major land use/land cover categories in
         different village type (in hectare).

 Land use/land         Big Village        %         Small Village     %         Aband        %
 cover                  (155 - 20                     (19 - 6                    oned
 Categories              houses)                      houses)                   Village
 Fc                        13013.9          24.9          6854.7     43.2       1652.4      28.1
 Fd                         9638.2          18.5          2799.2     17.6       1633.2      27.8
 Fb                        16098.0          30.8          3408.7     21.5       2030.0      34.5
 Sc11                         953.7           1.8          261.2        1.6      105.5       1.8
 Sc1                        2596.1            5.0          613.1        3.9      173.2       2.9
 Sc2                        2255.2            4.3          385.9        2.4        98.4      1.7
 Sc3                        4843.0            9.3          866.9        5.5        64.0      1.1
 Pdy                          770.2           1.5            13.4       0.1         0.0      0.0
 Wtr                           96.3           0.2            15.1       0.1         0.0      0.0
 Ndt                        1956.1            3.7          646.4        4.1      121.5       2.1

Table 2.4. Major land use/land cover types over different elevation gradient (in hectare).

      Major Land               800 - 900m            900 - 1000m              1000 - 1100m
      use/land cover
      Fc                              65080.5                53071.7                 3065.8
      Fd                              49966.2                19806.5                  485.8
      Fb                              84295.6                21682.2                      43.6
      Sc                              34227.4                12745.4                  173.5
      Pdy                                566.5                  319.5                      0.0


        The analysis of time series NOAA AVHRR satellite data of Lao P.D.R. at the macro
scale identified Oudomxay province of northern Laos as one of the “hot spot” area for
further investigation. Available national reports also emphasized that among the northern
provinces of the country, Oudomxay exhibits one of the highest hectarage covered by slash
and burn cultivation and with a fastest growing population.

        An area having a dimension of 60 x 60 km was investigated using a high spatial
resolution SPOT data acquired on 26 March 1992. Various stages of shifting cultivation
practices from land preparation (burnt and exposed soil) up to fallow fields covered by thick
bushes were identified both in the satellite image and on the ground. Shifting cultivation
plot size ranges from 2 to 650 ha were distributed in the watershed of two major river
systems, Nam Tha and Nam Beng. Proximity to these rivers and a road along the Nam Beng
that connects Xai and Pak Beng districts provided a strong market pull for small and large
villages to be attached with these natural features and available infrastructure in exchanging
their goods and services.

        Satellite image interpretation approximates that 42% of the whole study area is
subjected to human exploitation under various form of agricultural practices from lowland
to upland, and the remaining 32% are still covered by evergreen dominated type of forest.
Narrow valleys offer small area allotted for paddy cultivation.

        Combining the location of the village with GIS database suggests that their influence
on their surrounding ecosystem in utilizing and looking for new agricultural plots creeps far
beyond their backyard. The presence of plots where soil is exposed or recently burnt site
shows that human activity is still in effect despite the absence or remote distances of their
villages with respect to that area. The rolling topography in a middle elevation gradient
harbors the large proportion of remaining forest in the watershed where upland cultivators
showed their strong preference to satisfy the existing demand for available and fertile

        The intensity of occupation of some areas, and the considerable size of the
agricultural plots, indicated a high pressure on the land and low yields per hectare. This
combination most certainly will cause a long-term decline in the productive potential of the
uplands for both agriculture and forestry.

        Though there was no comprehensive and large scale drastic land transformation
found in the multi-temporal analysis of 1 km resolution AVHHR data for LAO P.D.R., the
sporadic spectral variations observed in the northern part of the country leads to a detailed
and timely investigation of its resources. The national assessment of the land cover of the
country while giving attention to an area where major land cover transformation is occurring
render a direct information link and challenge to generate the appropriate and punctual
actions for the identified agent of land degradation.


IUCN (1988) Technical Report on Shifting Cultivation in Laos. Gland, Switzerland,
      December 1988.

Lao P.D.R., Ministry of Agriculture and Forestry, (1992). Forestry Policy in Lao P.D.R.
       Regional Expert Consultation on Forestry Policy Developments in Asia and the
       Pacific. FAO-RAPA, Bangkok, Thailand. 5 - 9 October 1992.

Lao P.D.R., Ministry of Agriculture and Forestry, (1990). Lao People's Democratic
       Republic Tropical Forestry Action Plan (First Phase), Executive Summary.
       Vientiane, Lao P.D.R., August 1990.

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