Tallying up the biomass in a forest—and monitoring changes to it—is no easy task. You can cordon off a patch of forest and use tape measures to assess tree growth, hoping your patch is representative of the wider forest. Or you can turn to aerial or satellite photography—if the pictures are available and sharp enough. But even the best cameras can9t see past the forest canopy to the understory below. On 5 December, scientists gained a new tool for this tricky business when NASA9s Global Ecosystem Dynamics Investigation instrument was launched on a SpaceX rocket. The instrument, the size of a large refrigerator, uses a laser to see below the treetops. It is now mounted on the International Space Station, where it will begin to gather data on the height and 3D structure of tropical and temperate forests. The campaign will help scientists understand whether forests are slowing or amplifying climate change and identify prime habitat for valued species.

中文翻译：

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空间激光在 3D 中映射树木

统计森林中的生物量——并监测其变化——并非易事。您可以封锁一片森林并使用卷尺来评估树木的生长情况，希望您的补丁能够代表更广阔的森林。或者您可以转向航空或卫星摄影——如果图片可用且足够清晰。但即使是最好的相机也无法越过森林树冠看到下面的林下。12 月 5 日，当 NASA9 的全球生态系统动力学调查仪器在 SpaceX 火箭上发射时，科学家们为这项棘手的业务获得了一个新工具。该仪器有一个大冰箱那么大，它使用激光观察树梢下方。它现在安装在国际空间站上，在那里它将开始收集有关热带和温带森林的高度和 3D 结构的数据。