Pictures: Trees Cocooned in Webs After Flood

Cotton Candy Tree

Photograph courtesy Russell Watkins, U.K. Department for International Development

Seen in December 2010, a young girl stands next to a tree covered in webs in Sindh, Pakistan, near the intersection of two roads that had only recently reemerged from floodwaters.

At the height of the crisis, the flooded region covered an area the size of England. Nearly 2,000 people died during the disaster and 20 million people were affected, according to the Pakistani government. (Related: "Pakistan Flooding Because of Farms?")

"More people were affected by the flooding than the combined total of the Boxing Day Indian Ocean tsunami, 2005 Pakistan earthquake, [2010] Haiti earthquake, and Hurricane Katrina," John Barrett, head of DFID's Flood Response Team, said in a statement.

As part of the international response, DFID mounted the U.K.'s largest humanitarian operation yet.

Updated November 30, 2011

Webbed Trees

Photograph courtesy Russell Watkins, U.K. Department for International Development

The giant webs in Sindh, Pakistan, sometimes stretched from tree to tree, as seen above in December 2010.

"Any kind of vegetation that was above ground was affected, literally every kind of tree and bush," Watkins said of the widespread webs.

While unusual, trees cocooned in webs are not unprecedented. Scientists have reported similar webs in other parts of the world, the tropics in particular. In 2007, for instance, a superintendent at Lake Tawokoni State Park in Texas discovered a giant spider web among the trees.

Watkins said he didn't know what type of animal was responsible for the tree cocoons in Sindh. But in the case of Lake Tawokoni, scientists determined that dozens of spider species were spinning the communal webs.

Updated November 30, 2011

Natural Net?

Photograph courtesy Russell Watkins, U.K. Department for International Development

A web enshrouds a tree in Sindh, Pakistan, in a December 2010 photograph.

The unusual cocoons were a mixed blessing: The huge webs ultimately killed many of the trees they covered, perhaps by reducing the amount of sunlight reaching their leaves.

But for a while, the webs also seemed to help trap more mosquitoes in the region, thereby reducing the risk of malaria, Watkins said. (Related: "Modified Mosquitoes May Be Anti-Malaria Allies.")

Normally after a flood, the remaining stagnant water provides more opportunities for mosquitoes to breed. But people in Sindh reported far fewer mosquitoes than expected following the recent crisis.

Updated November 30, 2011

Death Shrouds

Photograph courtesy Russell Watkins, U.K. Department for International Development

Cocooned trees line the banks of a flooded rice paddy in Sindh, Pakistan, in December 2010. According to Watkins, the subsequent deaths of many of the web-covered trees has created a new problem for the residents of Sindh.

"The area is incredibly hot in summer, and there is very little natural foliage cover for people to use as shade to begin with," he said. Without the trees lining roads and fields, there will be little refuge from the summer sun.

(Related: "Extreme Storms and Floods Concretely Linked to Climate Change?")

Updated November 30, 2011

Bug Islands

Photograph courtesy Russell Watkins, U.K. Department for International Development

Trees rising above the floodwaters became safe havens for web-spinning animals in Sindh, Pakistan, as seen in December 2010.

Most of the floodwaters in Sindh and the surrounding region have now receded, and people are slowly returning to what's left of their towns and villages.

"Virtually 90 percent of displaced populations in Pakistan have returned, but most of the communities that were there were completely destroyed," Watkins said.

Updated November 30, 2011

Head Above Water

Photograph courtesy Vicki Francis, U.K. Department for International Development

In December 2010 a Pakistani man points to the height of floodwaters that swept through the village of Sindh in August.

At their peak, the flood waters were up to 20 feet (6 meters) deep in Sindh. By the time this picture was taken, the man's fields—seen in the background—were still under three feet (about a meter) of water.

"Officially, the humanitarian emergency response phase is over," Watkins said. "The focus now is very much on getting people's livelihoods back. We're working with the government of Pakistan, the UN, and local partners to help do that."

Updated November 30, 2011

New Pictures: Webs Blanket Flooded Australian Countryside

Photograph by Daniel Munoz, Reuters

Updated November 30, 2011