Suzanne's Mom's Blog

When I was a kid spending summers on Fire Island, we all thought the Sunken Forest the most magical place ever. But just imagine if a forest were so removed from the world that it harbored previously unknown species! Scientists in China are beginning to study a forest of tantalizing possibilities at the bottom of a huge sinkhole.

Stephanie Pappas reports at Live Science, “A team of Chinese scientists has discovered a giant new sinkhole with a forest at its bottom. 

“The sinkhole is 630 feet (192 meters) deep, according to the Xinhua news agency, deep enough to just swallow St. Louis’ Gateway Arch. A team of speleologists and spelunkers rappelled into the sinkhole on Friday (May 6), discovering that there are three cave entrances in the chasm, as well as ancient trees 131 feet (40 m) tall, stretching their branches toward the sunlight that filters through the sinkhole entrance. 

” ‘This is cool news,’ said George Veni, the executive director of the National Cave and Karst Research Institute (NCKRI) in the U.S., and an international expert on caves. Veni was not involved in the exploration of the cave, but the organization that was, the Institute of Karst Geology of the China Geological Survey, is NCKRI’s sister institute. …

“Veni told Live Science, [that] southern China is home to karst topography, a landscape prone to dramatic sinkholes and otherworldly caves. Karst landscapes are formed primarily by the dissolution of bedrock, Veni said. Rainwater, which is slightly acidic, picks up carbon dioxide as it runs through the soil, becoming more acidic. It then trickles, rushes and flows through cracks in the bedrock, slowly widening them into tunnels and voids. Over time, if a cave chamber gets large enough, the ceiling can gradually collapse, opening up huge sinkholes. 

” ‘Because of local differences in geology, climate and other factors, the way karst appears at the surface can be dramatically different,’ he said. ‘So in China you have this incredibly visually spectacular karst with enormous sinkholes and giant cave entrances and so forth. In other parts of the world you walk out on the karst and you really don’t notice anything. Sinkholes might be quite subdued. … Cave entrances might be very small, so you have to squeeze your way into them.’ 

“In fact, 25% of the United States is karst or pseudokarst, which features caves carved by factors other than dissolution, such as volcanics or wind, Veni said. About 20% of the world’s landmass is made of one of these two cave-rich landscapes. 

“The new discovery took place in the Guangxi Zhuang Autonomous Region, near Ping’e village in the county of Leye, according to Xinhua. Guangxi is known for its fabulous karst formations, which range from sinkholes to rock pillars to natural bridges and have earned the region UNESCO world heritage site designation.

“The sinkhole’s interior is 1,004 feet (306 m) long and 492 feet (150 m) wide, Zhang Yuanhai, a senior engineer with the Institute of Karst Geology, told Xinhua. … Chen Lixin, who led the cave expedition team, told Xinhua that the dense undergrowth on the sinkhole floor was as high as a person’s shoulders. Karst caves and sinkholes can provide an oasis for life, Veni said.

‘I wouldn’t be surprised to know that there are species found in these caves that have never been reported or described by science until now,’ [team leader] Lixin said.

“In one West Texas cave, Veni said, tropical ferns grow abundantly; the spores of the ferns were apparently carried to the sheltered spot by bats that migrate to South and Central America.

“Not only do sinkholes and caves offer refuge for life, they are also a conduit to aquifers, or deep stores of underground water. Karst aquifers provide the sole or primary water source for 700 million people worldwide, Veni said. But they’re easily accessed and drained — or polluted.” More at Live Science, here. No firewall.

The Washington Post offers more on the forest. Reporter Marisa Iati writes, “Large sinkholes are known in Chinese as ‘tiankeng,’ or ‘heavenly pits.’

“The sinkhole near Ping’e village is known to local residents as Shenying Tiankeng, or ‘the bottomless pit.’ From a distance, the cliff looks like a pair of soaring wings, the Guangxi Daily newspaper reported.

“The researchers arrived at the sinkhole May 6 and saw dense trees blocking the bottom of the pit, the newspaper reported. They used drones to explore the area and then rappelled and hiked to the bottom for several hours, passing dense thorns and fig plants. They found three caves in the wall that may have formed early in the sinkhole’s evolution, Zhang Yuanhai, senior engineer at the Institute of Karst Geology of China Geological Survey, told Chinese state-run news agency Xinhua.

“While trees exist in other sinkholes, Veni said they can only grow if the hole is shallow enough and has a big enough opening to let in sunlight. The newly explored sinkhole is almost definitely home to small animals, such as insects, that are currently unknown to scientists, he said.”

More at the Post, here.