南宋森林覆盖率及其变迁原因研究

The forest coverage in the Southern Song and the reasons for its changes

中国历史上曾经是一个多林的国家,经考证分析在4000年前的远古时代,森林覆盖率高达57%左右。其中,东南部地区森林覆盖率高达80%—90%,部分地区甚至高达90%以上;西北地区的森林覆盖率则在26%以下。随着人类社会历史的发展,不仅森林资源日趋减少,森林结构及其地域分布也不断变化。到公元1000年左右的北宋前期与1200年前后的南宋中后期,森林覆盖率整体分别降低到42%与40%左右。但仅从南宋所辖政区范围约205万平方千米计,森林覆盖率当时则仍高达65%左右。不过,即使在南宋境内,其不同地区森林覆盖率的分布及其变化也有较大的差别。造成南宋不同地区森林覆盖率分布变化的主要原因依次是毁林垦荒,建筑用材,薪炭消耗,车船、家具、农具与棺椁等各种木器制作,矿冶、煮盐与烧制瓷器用材,栈道修建与战乱伐木对森林的砍伐等。从整体的生态环境状态看,南宋仍然处于相对良好的生态系统平衡阶段。

China had been a land rich in forests. It was investigated that her forest coverage is as high as 57% in the remote ancient time 4000 years ago. In the southeast China, the coverage was up to 80%-90%, even above 90% in some areas, while it was down to 26% in the northwest. As the society evolutes, not only forests became less and less, but also their structure and locations was keeping on changing. Up to the early Northern Song around A.D.1000 and the mid-and late Southern Song around A.D.1200, the coverage had decreased to about 42% and 40%. In the area about 2.05 million square kilometers under the Southern Song's jurisdiction,however, it was still up to 65%. Even in the jurisdiction, however, the coverage rates in different regions were considerably different.The key reasons for the differences and deforestation were: reclamation; shelter buildings; fuel; wooden goods such as vehicles,boats, farm tools, coffins; fuel in mining,boiling salt and making porcelains; plank roads and deforestation for wars. On the whole,however, the ecology in the Southern Song was still relatively sound and in balance.