The Effects of Rainfall Exclusion on an Amazon Forest

干旱对亚马逊森林的影响干旱日益威胁世界主要热带雨林。厄尔尼诺现象导致严重干旱和火灾对森林的广泛破坏。在这个项目中，研究人员正在通过实验排除巴西一公顷(2.5英亩)森林中的降雨来展望亚马逊雨林的未来。这项实验将确定热带雨林在树木开始落叶、停止生长和繁殖以及死亡之前可以忍受多少干旱。研究人员还将研究干旱如何影响热带雨林在大气化学变化中的作用。把雨挡在雨林之外可不是一件容易的事。这项研究的后续项目雇佣了26名工人，花了一年的时间建造了一个木制框架，其中包含6100块塑料面板，固定在森林地面2-4米的高度。排水沟将雨水从现场带走。该项目还在离地面10层的森林树冠上建造了8座塔，以监测树叶的生理和动态。此外，还挖了3层楼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.