The Effects of Rainfall Exclusion on an Amazon Forest

干旱日益威胁着世界上主要的热带雨林。厄尔尼诺现象会造成严重的干旱和大面积的森林火灾。在这个项目中，研究人员通过实验排除巴西一公顷（2.5英亩）森林的降雨，来观察亚马逊雨林的未来。这个实验将决定雨林在树木开始落叶、停止生长和繁殖、死亡之前能忍受多少干旱。研究人员还将调查干旱如何影响雨林在大气化学变化中的作用。从雨林中排除雨水可不是件容易的事。这项研究的项目雇佣了26名工人，用一年的时间建造了一个由6100块塑料板组成的木框架，该框架位于森林地面上2-4米的地方。排水沟把雨水从场地带走。该项目还在森林树冠上建造了8座塔，距离地面10层，用于监测树叶的生理和动态。此外，还挖了3层深的竖井来研究土壤水分和根系。

Abstract00-75602NepstadThe effects of rainfall exclusion on an Amazon forestDroughts increasingly threaten the world's major tropical rainforests. El Nino episodes cause severe drought and widespread forest damage by fire. In this project, the investigators are looking into the future of the Amazon rainforest by experimentally excluding rainfall from a one-hectare (2.5 acre) patch of forest in Brazil. This experiment will determine how much drought the rainforest can tolerate before its trees begin to lose leaves, stop growing and reproducing, and die. The researchers will also be investigating how drought affects the role of the rainforest in the changing chemistry of the atmosphere. It is no small task to exclude rain from a rainforest. The project upon which this research follows hired 26 laborers for a year to build a wooden frame containing 6100 plastic panels held 2-4 meters above the forest floor. Gutters carry the rainwater away from the site. The project also built 8 towers into the forest canopy, 10-stories above the ground, to monitor the physiology and dynamics of leaves. In addition, shafts 3-stories deep were dug to study soil water and roots.