人口增長、森林砍伐與明代北京生活燃料的轉變

Population Growth, Deforestation and Fuel Substitution in Ming Beijing

本文旨在考察明代中葉以後，北京居民生活燃料由木柴轉為煤炭的背景，及明中葉以後居民大量使用煤炭的情況。透過對城市人口、森林盜伐與官方柴炭制度的探討，可以看到北京城內及城郊人口的增長，導致飲食炊爨、居室建材等需求加大，從而也引發了山林盜伐的問題。官方雖一再重申禁令，時而也展開拘捕行動，但情況還是未見好轉。在不斷濫伐的情況下，燕山山脈上的山林，在十六世紀初幾已無木可採。另一方面，官方為供應皇宮及官府使用，在北京西南面的太行山北段，設立了專責採燒柴炭的柴炭廠，差遣夫役上山砍伐、燒取巨額的木柴及木炭。在正統七年（1442），官方下令採燒的柴炭，曾達到五萬七千多公噸。後來數字雖有所下降，但在十六世紀中葉，每年需要供應的數額還是達到三萬餘公噸。由於每年所採燒的木材極多，也就造成太行山森林遭到嚴重破壞，在十六世紀初也面臨淺山光禿的問題。此後，採燒柴炭多須深入深山。由於自十五世紀中葉以後，北京附近森林遭受官民砍伐而日漸枯竭，其所能供應北京居民日常使用的柴薪，亦日漸稀少，價格相對增高。在此情況下，北京居民乃轉而尋求便宜耐燒的煤炭。大約在十五世紀後半葉起，業者在北京西面禁山開鑿煤礦的記載已日見增多，而居民使用煤炭也日益普遍。明代早期，北京居民生活燃料主要取自林木的情況，自是在十六世紀以後，漸漸轉變為以煤炭為主。隨著時間的發展，這種情況在明代後期更加明顯。明代北京在生活燃料上的轉變，是都市發展引發周邊生態變遷的明顯例子。而在森林消失、導致居民大量使用煤炭之後，城市內部的環境變遷也跟著發生。在明代後期，使用煤炭又引發廢土堆積與空氣污染問題。這些問題之所以出現，其實是周邊環境生態變遷進一步衍生的結果。如此看來，北京在十六世紀後半，已經存在環境惡化的問題。

This article investigates why people of Beijing started to turn coal instead of logs after the middle Ming Dynasty. The records of the city's population, illegal logging and the government's fuel policy showed that Beijing's population boom, which resulted in a stronger demand of cooking fuel and construction materials, had led to illegal logging. Despite repeated prohibitions and arrests, the situation only worsened. In the early 16th century, there were hardly any trees on the Yan Mountain north of Beijing. On the other hand, to provide huge amounts of fuel for the Palace and offices, the government set up a charcoal works on the northern Taihang Mountain, which is southwest of Beijing. In 1442, 57,000 tons firewood and charcoal were burned for official purposes. Even though the quantity declined later, it still consumed 30,000 tons firewood and charcoal a year during the middle of the 16th century. The excessive and indiscriminate logging led to the depletion of forests nearby. Since then trips deep into the mountains for fuel-wood gathering became essential. After the middle of the 15th century, forests around Beijing disappeared due to extensive logging. The prices of logs also went up. Therefore people started to use easily available coal. Since the late 15th century, written accounts of coal mining in the mountain west of Beijing were increasing. In the early Ming, Beijing's households burned logs. Since then, more and more adopted coal burning especially during the late Ming. The city became so dependent on West Mountain's coal mine that any northern invasion that crossed the Great Wall would cause a coal supply problem. Fuel substitution in Beijing throughout the Ming Dynasty was a good example of environmental change caused by urban development. After the loss of forests and the mass consumption of coal, the city's environment also changed. Ever since the late Ming, coal-burningcaused problems such as earth dumping and air pollution were worsening. These problems were collectively contributed by all kinds of environmental changes. Evidently, the city of Beijing was suffering from the decay of its environment since the late 16th century.