|Conservation and Development in Northern Thailand. Proceedings of a Programmatic Workshop on Agro-forestry and Highland-Lowland Interactive Systems, Held at Chiang Mai, Thailand, 13-17 November 1978 (UNU, 1980, 114 pages)|
|Subcommittee reports, plenary discussion, and recommendations|
Very important aspects for a study of highland-lowland interactions in Northern Thailand are climate, soils. and soil erosion, in association with mapping of cover types and land-use patterns. For climatic conditions, rainfall characteristics are particularly important; soil properties must be detailed; and soil erosion and sediment transport must be determined.
Climatic observations have been carried out at the following stations that are located in the vicinity of the Huai Thung Choa field area: (a) the station itself (alt. 1,200 m); (b) Huai Kok Ma (1,100 m); (c) Doi Chiang Dao (above 1,000 m); (d) Royal Ang Kang Research Station (1.400 m): (e) Chiang Mai University Geography Department and Multi-cropping Project, Department of Agriculture. and Weather Station at Chiang Mai Airport (354 m). (f) Mae Sa Watershed Project (about 800 m); and (9) Chang Kien Station (200 m). Some of these localities have climatic data over a period of more than 10 years.
A very general soil survey may be available from the Land Development Department, Ministry of Agriculture. Geological maps at 1:1,000,000 and 1250,000 should be available. but these will be of limited value.
Available Data-Soil Erosion
There are very few studies concerning soil erosion. Run-off amounts. together with transported materials are observed at several stations but there is nothing available for the immediate research area (cf. Kunstadter et al. eds., 1978, chaps. 7 and 8).
Daily values for rainfall as well as humidity must be collected for as long a period as possible. Also there is critical need for detailed knowledge of distribution of rainfall intensities and standard climatological observations throughout the Huai Thung Choa field area as a basis for establishment of an applied topoclimatology. This should lead to statistical analysis of occurrences. frequencies, return periods, lapse rates, and secular changes. A minimum of 10 rainfall recorders and thermographs should be distributed throughout the field area, and a full topoclimatological unit should be established at the station itself.
Investigation of soil types. chemical and physical characteristics should be undertaken as a basis for soils mapping and soil erosion studies. This will also provide data for vegetation regeneration studies and productivity.
Research Needs-Soil Erosion
A series of observations on actual soil erosion processes must be made through a range of slopes, aspects, and soil and vegetation cover types. Water discharge, erosion rates, and sediment transport must be observed for the local watershed. Differentiation between natural and man-made, or man-augmented, processes should be attempted.
Two to three months are required for training observers in each of the three categories-climate. soils, and soil erosion. It will probably be necessary to make provision for adding two scientist-consultants to the project for a period of two or three months.
The cost of climatological instrumentation may be supported by certain Japanese foundations. A minimum of one year is required for the topoclimatologicai study and it should begin during 1979. The soil mapping may need three years. Soil erosion studies should be carried on for three to five years and preferably on a permanent basis. After establishment through the central UNU project this could possibly be taken over by the Royal Forestry Department. We expect that support can be obtained through collaboration with local (Chiang Mai and Government) agencies and institutions. Much of the effectiveness of these proposals, through the opportunity for their wider applications, will depend upon provision of a good topographic and thematic map base (see the report on mapping and cover type data requirements).