基于卫星观测系统功能的改善，人们得以更加详细地了解巴西热带雨林地区树木的损失状况。美国一项最新的研究成果显示，这一区域的树木损失程度远远超出了人们曾经的预想。

    据美联社10月20日报道，以前，在巴西热带雨林的皆伐地区（clear-cut areas，林木一次性被伐光的地区），树木损失情况都被卫星观测系统监控着，但这种方法却发现不了人们对个别树木的砍伐行为。现在，一种更为详细的卫星观测系统让这种选择性的伐木行为得以被发现。最新的观测结果显示，在这一地区，树木遭到砍伐的情况比研究人员先前预想的更加严重。

    主要研究人员、美国卡内基研究院的格雷戈里·艾斯纳表示，每年，选择性伐木行为都会使一个面积相当于美国康涅狄格州大小的区域受到扰乱。艾斯纳在一份声明中说，选择性伐木对很多植物和动物的影响都是消极的，而且还增加了腐蚀和火灾的发生。另外，这样还会使该地区每年向大气中释放的二氧化碳量增加25％。

    研究人员发现，非法伐木的行为甚至还出现在了一些受到保护的国家林地、公园和本地土地中。研究人员对此表示，我们曾经预计砍伐面积会很大，但是实际情况比我们预想的还要糟糕很多。 　

    报道说，这份新的研究结果将被发表在本周五（10月21日）出版的《科学》杂志上。

    Loss of trees in the Brazilian rain forest is much worse than had been thought, according to a new study. Losses in clear-cut areas where all trees are removed have been monitored by satellite observations, but those were not able to detect the cutting of individual trees in areas where others are left behind.

    Now, a more detailed satellite observation system is able to detect selective logging, and the findings show much more widespread timber harvests than had been thought, according to a report in Friday's issue of the journal Science.

    Annually, selective logging disturbs an area totaling about the size of Connecticut, according to lead author Gregory Asner of the Carnegie Institution of Washington and Stanford University.

    "Selective logging negatively impacts many plants and animals and increases erosion and fires. Additionally, up to 25 percent more carbon dioxide is released to the atmosphere each year, above that from deforestation, from the decomposition of what the loggers leave behind," Asner said in a statement.

    Illegal logging was even discovered in some protected national reserves, parks and indigenous lands, the researchers found.

    "We expected to see large areas of logging, but the extent to which logging penetratesdeep into the frontier is much more dramatic than we anticipated," said co-author Michael Keller of the U.S. Forest Service.