本文主要考察明清時期山西中、南部山區的生態變遷情況，特別是百姓不斷向山上開墾，與砍伐森林，造成水土保持破壞，一遇到下雨，滾滾洪流奔騰而下，不僅衝擊到堤防，也使水利系統淤塞，失去灌溉的作用。大約在十五世紀下半，濫伐樹木與山區開發的問題日趨嚴重，百姓甚至放火燒山進行墾殖。而其所造成的不良影響，也有一些士人特別指出。在十七世紀，許多山地的梯田已直達山頂，而山上光禿無樹木的記載也相當多。在此情況下，社會上出現兩種森林保育的手段，其一為造林植樹，其二為禁止砍伐。前者的例子雖然較少，但其積極性較高，有些樹木甚至一直保留至十九世紀還在。至於後者，在清代以後越來越多，但由於森林資源已越來越少，故即使許多廟林禁止砍伐，卻不段出現住持或僧道盜賣林木之事。而禁山的森林之所以被盜砍，木材商人的高價誘惑可能是一個主因。整體而言，到十九世紀後期，除了少數山地因為高峻，尚有若干森林存在，老虎等動物亦棲息其中之外，大部份的山區已經沒有較粗的樹木，而建材與木柴的價格也越來越高。而百姓因為生存的壓力，持續向高海拔開墾，其日積月累所發揮的破壞力相當驚人，應該是生態環境變遷的根源所在。

This article mainly focuses on the ecological transformation in the central and southern mountainous region of the Shanxi Province, particularly when people continuously developed the mountainous land and lumbering in the forest causing the erosion of water and soil. When it rained, fast currents, inundating down the slop, not only destroyed flood levees but also the water conservancy system causing it to lose its irrigation functions. In the late 15(superscript th) century, the problems of over lumbering and development of the mountainous regions became increasingly serious; people even burned the whole mountain for cultivation. Some specialists have pointed out the long term negative effects of such rapid development. In the 17(superscript th) century, many terraced fields reached the top of the mountain, and many records have indicated bare mountains without any trees. Under such conditions, there were two methods of preserving the forest, tree planting and restricted logging. Although the first method had fewer examples, it was positively constructive; some trees were even kept until the 19(superscript th) century. As for the second method, it became more effective in the Qing Dynasty. Due to the diminishing of the forest's natural resources, even the temple controlled forest was restricted to the felling of trees which caused the monks to steal and trade lumber illegally. Until the late 19(superscript th) century, there were only a few steep and inaccessible mountains that had forests left with animals like tigers roaming; most mountains had no broad trees. Moreover, prices for building material and firewood were on a constant rise. In general, under the pressure of survival, people were forced to cultivate the higher elevated land. Its accumulated destructive power was astonishing; this is also an important root cause of the ecological transformation.