生業としての伝統的焼畑の価値 : ラオス北部山地における空間利用の連続性

Abstract

自然の力を利用して作物栽培を持続的かつ循環的に営むことができるのが焼畑農業である. 先人たちは, 土地に合った耕作と休閑のパターンを守り, 焼畑を何世紀にもわたって存続させてきた. しかし, 遅れた農法と見なされた焼畑は, 世界各地で規制され, その面積は急速に縮小し, 消滅の危機を向かえようとしている. 本研究では, 現在でも広く焼畑が営まれている東南アジアのラオス北部を事例に, 焼畑を持続させてきた自然資源の循環的利用や焼畑を営む人びとの生業維持の戦略にフォーカスをあてることで, 焼畑の生業にとっての価値を再考することを試みた. その結果, 焼畑の特徴は「区分」ではなく「連続性」に特徴づけられることを示した. 火入れ後の1 年間は食料を生産する「畑」であるが, その後の休閑地となっている長期間は植物の侵略と遷移が繰り返され, また各種の生物が生きる「森」である. 焼畑は畑と森の両方の機能をあわせ持ち, 森林を破壊する農法と捉えるのは適切ではない. さらに, 生業の面から焼畑を捉えると, 作物栽培を行った後, 同じ場所で牛の刈跡放牧を行い, 植物や昆虫を採取し, 狩猟まで行っている. 生態学的な連続性に加えて, 生業の連続性という特徴も有する. 焼畑を「連続性」の視点から再考すれば, 従来とは異なる価値を見いだすことができるのである.

Swidden agriculture tends to be viewed as outdated in comparison to intensive modern agriculture. From the viewpoint of ecology, however, swidden agriculture represents a sustainable and cyclical farming method that makes use of natural processes and is, by no means, outdated. However, as swidden agriculture has come under increasing regulation around the world, the area of land under swidden cultivation has declined dramatically, and the practice faces possible extinction. In this study, through a case study of northern Laos where swidden agriculture is still widely practiced, I re-examined the value of swidden agriculture in terms of people, nature, and livelihood, focusing on the cyclical use of natural resources in continuous swidden agriculture and subsistence strategies employed by swidden farmers. As a result, it was found that swidden agriculture involves an everchanging mix of space that includes swidden fields and fallow forests at various stages of succession; as such, it is not possible to consider each space separately. Swidden agriculture is best characterized by "continuity, " not "classification." Swidden land can be considered an "agricultural field" for food production in the first year after slashing and burning; however, over the long fallow period that follows, it returns to being a biologically diverse "forest" after repeated cycles of invasion and succession of vegetation. Furthermore, if we consider swidden agriculture from the standpoint of livelihood activities, it can be seen that the same land, after being employed for food production, is used for stubble grazing of cattle, and further utilized as a source of plants and insects, and even for hunting. Thus, swidden agriculture is characterized by "continuity" not only in terms of ecology but also livelihood. Reconsidering swidden agriculture from the standpoint of "continuity, " brings to light benefits of the practice that have not conventionally been recognized.