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| 1 - Overview |
9 - Birds |
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FOREST FIRES Forest fires in this region are all started by man for various reasons; these include hunting, clearing land for agriculture, grazing, or settlements and arson. Lowland deciduous forests are especially prone and local people falsely believe that more edible mushrooms are produced after burning. The plants found in these places are mostly leafless when fires occur, mostly in the dry season from January to April. This kind of vegetation is able to recover, albeit less vigorously, when the rains begin in May. Upland forests, which are evergreen, do not have this capacity to survive after fire. Places that have been burned do not readily return to their original condition. Secondary or replacement growth develops in these burned areas and usually slowly, perhaps taking 20-30 years, to begin to develop into the original primary growth. This is the basic situation in slash & burn (swidden) agricultural systems where agricultural land was used for a few years after clearing and burning and then left to recover for several to many years. This primitive, migratory system of life is no longer sustainable in Thailand since there are too many upland, mostly overpopulated hill-tribe villages and a lack of available land. The basic problem in northern Thailand, as well as in other countries, is that the destroyed primary forest has not been allowed to regenerate. This is because of perpetual destruction by man and an overall degradation of biodiversity resulting from this. Fire in both lowland and upland forest kills many seeds, almost all seedlings, and sterilizes the soil. Organic matter, especially leaf litter, disappears as well as destroying or damaging the already decomposed upper (organic) layer of soil. Fires can also damage or destroy shrubs and trees. Many fungi, insects, and other mostly microscopic organisms also perish. Many or these organisms are especially important for soil enrichment and plant growth, e.g. microrhiza, termites, and worms. Destruction of the organic layer also alters soil structure, thus the absorbing ability of soil is damaged. This often results in soil runoff after the first rains in May where the potentially valuable ash, which contains some useful nutrients, is lost. The soil becomes more impoverished and is rendered more exposed due to limited vegetation cover, hotter, and loses more moisture due to evaporation. This is a major cause of water catchment degradation and decreases of available water during the dry season. Along with fire there is usually an increase in grazing and hunting in most areas. Cattle effectively damage or destroy much forest regrowth as well as compacting the soil. Hunting removes birds and mammals that are essential for fruit and seed dispersal. The overall result is vast, open areas with poor soil that will take many decades to show signs of recovery. The Thai government has been unable or possibly unwilling, to alleviate this disaster and has been totally ineffective in any kind of suitable or sustainable reforestation. |
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