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处于危险中的资源—受到威胁的雨林
 秘鲁毁掉的树林用作养牛场. (Photo by R. Butler)
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写 Rhett Butler. 翻译 Che Fei
07/12/2007
养牛场
从1960年代到1990年代早期亚马逊平原的经济毁林并不是因为伐木或者开矿,而是一些养牛的农场主和土地投机者在烧掉了大片的雨林之后种植了非洲操以用作牧场.在巴西,政府统计得知在1966-1975年间有38%的森林被毁用作大片的养牛牧场.在中美洲的部分地方,养牛牧场更加普遍,比如哥斯达黎加,使拉丁美洲毁林比率最严重的国家.但1970到1980年间,投机者烧掉雨林把它转变成养牛场,来应对美国对牛肉的需求.
在1970-1980年间,在中美洲把大量的土地留作养牛牧场其实是一个非常差的选择,因为大部分的雨林土壤都是特别肥沃的（尤其是火山和洪涝平原的土地).举个例子,在洪都拉斯养牛场所占的土地超过全国肥沃土地的40%.在回归线之间放牛相对比较低的：最初清理的土地每公顷可能养活一头牛,但是在6-8年后,每头牛大概会需要5公顷的土地.
尽管如此,养牛仍然是比较吸引拉美国家的一个选择.在简单的清理森林之后,给土地上带来几头动物,移民者和开发者就可以拥有这些土地的所有权（在巴西非常显著）.他们常常选择牛超过其它的选择因为养牛的成本较低,而且很容易通过市城得到较高的回报.另外,牛的风险投资同经济作物相比比较低,因为经济作物会受野生价格的波动和害虫的侵害.
在拉丁美洲一些土地投机者把大片的热带雨林清理用作养牛牧场.许多国家在促进这种土地使用制度的转换,这些丰富多产的土地富裕了土地拥有者和投资者. 当牧场的实际价格超过了森林的实际价格时,土地的清理是抵抗通货膨胀的一种很好的方式,在1980到1990年之间许多发展中国家都发生了通货膨胀(巴西在1993年是百分之2500,委内瑞拉在1993-1998年间是百分之13340).在许多的例子中,土地价格的增长要比通货膨胀大,使得这些土地清理成为一个很好的投资而不用管土地的使用.另外,在高通货膨胀的时期,评价牛的价格和牛奶的服务,他们可以提供的利息率比把钱留在银行得到的利息率更高.
上面的饼状图显示的造成亚马逊毁林的原因是基于中间估计的数字范围.
复习题:
- 拉丁美洲毁林最严重的原因是什么?
- 土地投机者为什么要清理土地?
[打印版]
续: 水电,污染,狩猎
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