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| 1 - Overview |
9 - Birds |
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FOREST TYPES (Maxwell, 2001) The lowlands of northern Thailand consisted of deciduous facies in which the vegetation was leafless during the hot-dry season. Most of the original components of the vegetation have been destroyed and the present flora is composed of cultivated species and secondary growth plants. Some of this growth includes deciduous dipterocarp-oak forest (dof) which is dominated by Dipterocarpaceae and Fagaceae trees. This is a secondary, fire-climax kind of vegetation which before humans came, included Pinus merkusii Jungh. & De Vries (Pinaceae, 2-needled pine) – which would have been primary (i.e. stable) growth. Deciduous forests extended up to c. 850 m. and included areas with Tectona grandis L. f. (Verbenaceae, teak) which has been eliminated in almost all areas. This was a primary (i.e. original, perpetual) kind of forest which included many different kinds of deciduous trees and other plants with much bamboo (bb/df). This kind of forest is totally different from (dof) and when degraded can usually return to (bb/df), but when cleared reverts to (dof) which may in centuries without human distrubance return to (bb/df). Between c. 850 m - c. 1000 m there is a zone of mixed evergreen + deciduous species (mxf) which includes many plants which are confined to this facies. It is not a transition zone between lowland deciduous and upland evergreen forest. Most (mxf) in Thailand have been destroyed, including that on Doi Lohn. This kind of forest is immediately recognised by the presence of Dipterocarpus costatus Gaertn. f. (Dipterocarpaceae), a massive tree 30-40 m tall, which has been extirpated for its valuable wood. Above 1000 m the forest is primary and evergreen (egf). This kind of forest is much more common, albeit being rapidly destroyed, in northern Thailand. The original cover of the upper part of the Mae Lai Valley (above 1000 m) is still present and mostly intact. The north ridge and, to a lesser extent, the southern one has an evergreen hardwood + 3-needled pine facies, mostly between 1450 m -1525 m.
TEA/MIANG PLANTATIONS Camellia sinensis (L.) O.K. var. assamica (Mast.) Kita. (Theaceae) is a native evergreen treelet or small tree found in (egf). Leaves from this plant provide a tea drink or a fermented product which is chewed (miang). These plantations are common in upland areas from c. 900-1400 m. and are the only local agro-forestry system which is sustainable, environmentally safe (“friendly”), and profitable. This system requires intact forest and a permanent, clean water supply, but does not need pesticides and synthetic fertilisers, while fire and grazing are forbidden. Tea/miang cultivation is a major reason why the (egf) on the west side of Doi Lohn is still viable. FOREST CONSERVATION The tea/miang-dependent villagers on the west side of Doi Lohn are quite aware of the necessity of preserving the (egf) in their valleys. Without (egf) and water they would be unable to continue growing this crop. They have been able to live for several generations in this area without severly degrading it. The deplorable contrast can be vividly seen in hill-tribe areas, many less than a generation old, where uncontrolled, rapacious agricultural methods have left vast areas of barren land, eroded and infertile soil, and water poisoned with pesticides. References Maxwell, J. F. 2001. A Reassessment of the Forest Types of Thailand. In J. F. Maxwell & S. Elliot. Vegetation and Vascular Flora of Doi Sutep-Pui National Park, Northern Thailand. Thai Studies in Biodiversity, 5: 1-17. |
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