Scientists may be about to upset one of the most cherished tenets of conservation: that trees save water.
The research, published yesterday by Britain's Forestry Research Programme, could mean that billions spent on forest projects in the developing world have been wasted.
New measurements suggest that forests soak up water from the ground and discharge it into the atmosphere as vapor at least twice as fast as grasses, low-lying scrub or most food crops. By 2025, around 4 billion people -- half the world's population -- will be short of water. India, China, Costa Rica and Panama have invested in huge forestry programs to conserve water.
For decades, conservationists have argued that forests serve as a kind of sponge, collecting water during the rainy season and releasing it throughout the year. But in many cases, trees may make things worse.
"Generally, forests evaporate a lot more water than other vegetation types," said Ian Calder, of the center for land use and water resources research at the University of Newcastle.
"There are two quite simple reasons. One is that they tend to have deeper roots than shorter crops, and they keep on transpiring in dry seasons. The other simple reason is that they are tall, and when they are wet, their surfaces evaporate off much more quickly ... This is, essentially, why we all hang up our washing on the line to dry rather than leave it on the ground," he said.
Calder and British colleagues worked with scientists at the Free University in Amsterdam, as well as colleagues in Colombia, Costa Rica, Germany, Canada, India, South Africa, Sweden, Switzerland, Tanzania and the US. Their report shows evidence of falling water tables and reduced stream flows where forests have been planted.
In Himachal Pradesh and Madhya Pradesh in India there have been falls of up to 25 percent in water yield.
CONFRONTATION: The water cannon attack was the second this month on the Philippine supply boat ‘Unaizah May 4,’ after an incident on March 5 The China Coast Guard yesterday morning blocked a Philippine supply vessel and damaged it with water cannons near a reef off the Southeast Asian country, the Philippines said. The Philippine military released video of what it said was a nearly hour-long attack off the Second Thomas Shoal (Renai Shoal, 仁愛暗沙) in the contested South China Sea, where Chinese ships have unleashed water cannons and collided with Philippine vessels in similar standoffs in the past few months. The China Coast Guard and other vessels “once again harassed, blocked, deployed water cannons, and executed dangerous maneuvers” against a routine rotation and resupply mission to
GLOBAL COMBAT AIR PROGRAM: The potential purchasers would be limited to the 15 nations with which Tokyo has signed defense partnership and equipment transfer deals Japan’s Cabinet yesterday approved a plan to sell future next-generation fighter jets that it is developing with the UK and Italy to other nations, in the latest move away from the country’s post-World War II pacifist principles. The contentious decision to allow international arms sales is expected to help secure Japan’s role in the joint fighter jet project, and is part of a move to build up the Japanese arms industry and bolster its role in global security. The Cabinet also endorsed a revision to Japan’s arms equipment and technology transfer guidelines to allow coproduced lethal weapons to be sold to nations
Thousands of devotees, some in a state of trance, gathered at a Buddhist temple on the outskirts of Bangkok renowned for sacred tattoos known as Sak Yant, paying their respects to a revered monk who mastered the practice and seeking purification. The gathering at Wat Bang Phra Buddhist temple is part of a Thai Wai Khru ritual in which devotees pay homage to Luang Phor Pern, the temple’s formal abbot, who died in 2002. He had a reputation for refining and popularizing the temple’s Sak Yant tattoo style. The idea that tattoos confer magical powers has existed in many parts of Asia
ON ALERT: A Russian cruise missile crossed into Polish airspace for about 40 seconds, the Polish military said, adding that it is constantly monitoring the war to protect its airspace Ukraine’s capital, Kyiv, and the western region of Lviv early yesterday came under a “massive” Russian air attack, officials said, while a Russian cruise missile breached Polish airspace, the Polish military said. Russia and Ukraine have been engaged in a series of deadly aerial attacks, with yesterday’s strikes coming a day after the Russian military said it had seized the Ukrainian village of Ivanivske, west of Bakhmut. A militant attack on a Moscow concert hall on Friday that killed at least 133 people also became a new flash point between the two archrivals. “Explosions in the capital. Air defense is working. Do not