Białowieża Forest
Białowieża Forest in Poland is one of the largest and last remaining tracts of primeval forest in Europe. (Photo: Aleksander Bolbot/Shutterstock)

Old-growth forests are like time machines. Through their ancient ecosystems, we are able to go back hundreds or even thousands of years, back to a time when our wild environments remained free of an industrial footprint.

These exquisite lands are known under a variety of names depending on where you live, including primary forests, ancient woodlands, primeval forests and virgin forests, to name a few.

One outstanding example of an old-growth woodland is the Białowieża Forest. Stretching 1,191 square miles across the border of Poland and Belarus, Białowieża boasts a diverse array of biomes and represents one of the last bastions of ancient woodlands in northeastern Europe. It's also home to 900 European bison — that's about 25 percent of the world's total population of this rare species.

A herd of European bison in Białowieża.
A herd of European bison in Białowieża. (Photo: danm12/Shutterstock)

Despite the ecological and cultural value of Białowieża, only a small portion of it is protected as a national park. About 84 percent of this gorgeous ancient forest is located outside of that jurisdiction, leaving it unprotected from exploitation. Because of this, its integrity is now on a literal chopping block due to a controversial new logging law passed by the Polish government.

"Poland’s new far right government says logging is needed because more than 10 percent of spruce trees in the UNESCO world heritage site of Białowieża are suffering from a bark beetle outbreak," Arthur Neslen writes for The Guardian. "But nearly half the logging will be of other species. Oak trees as high as 150 feet that have grown for 450 years could be reduced to stumps under the planned threefold increase in tree fells."

Since the law was announced in March 2016, the country has been fiercely divided on the issue. Campaigners fighting to conserve the forest are receiving death threats, and there are allegations that an "environmental coup" is being staged by the pro-timber government following the sudden dismissal of 32 members of the state's council for nature, after many in the advisory body voiced opposition to logging.

A wetland in Białowieża.
A wetland in Białowieża. (Photo: Milosz_G/Shutterstock)

"The struggle to protect Białowieża and make it a national park is our Alamo," says Greenpeace spokesperson Katarzyna Jagiełło. "This place should be like our Serengeti or Great Barrier Reef. What happens to the forest here will define the future direction of nature conservation in our country."

Białowieża's current predicament is indicative of a larger trend of clear-cutting these one-of-a-kind ecosystems. Even if we set aside some lands for protection, the shrinking of surrounding tracts deals serious damage to the ecosystem as whole.

Learn more about what's at stake for these threatened biomes by taking a journey to a small handful of the world's last remaining old-growth forests:

Ancient Bristlecone Pine Forest — California, U.S.

Ancient Bristlecone Pine Forest
Ancient Bristlecone Pine Forest (Photo: Felix Lipov/Shutterstock)

If you want to experience what it's like to be in the presence of the oldest tree in the world, take a road trip to Inyo National Forest in southeastern California to see the Ancient Bristlecone Pine Forest. While the exact location of 4,847-year-old Methuselah — the oldest known tree — is fiercely protected, visitors can still walk among the gnarled grove and speculate about which one is the oldest.

Yakushima — Osumi Islands, Japan

Yakushima, Japan
Yakushima, Japan (Photo: 8 og/Flickr)

The misty "primary forests" of Japan's Yakushima island are perhaps best known for their stock of long-living Japanese cedar (Cryptomeria japonica).

Also known as "yakusugi" or simply "sugi," these magnificent trees are celebrated as Japan's national tree, and it's not uncommon to find them planted around temples and shrines. Yakushima's most notable example of this tree species is Jomon Sugi (pictured), which is estimated to be at least 2,300 years old.

Amazon jungle — Amazon basin, South America

Amazon rain forest
Amazon rain forest (Photo: Dr. Morley Read/Shutterstock)

The vast majority (60 percent) of this legendary rain forest is found in Brazil, though Peru, Colombia and a handful of other countries also host sizable chunks of jungle within their borders, too.

Despite its status as the largest rain forest in the world, the Amazonian ecosystem has been under constant siege of logging for decades. About 15 percent of the forest's total tree cover has been razed for cattle ranching since 1970.

The Tarkine — Tasmania, Australia

The Tarkine
The Tarkine (Photo: kuehdi/Shutterstock)

Nestled in the northwest wing of Tasmania is one of largest undisturbed tracts of cool temperate forest in the world — the Tarkine. Often described as a "relic" of the prehistoric super-continent, Gondwanaland, this lush, forested wilderness is home to more than 60 species of rare, endangered species, including the famous Tasmanian devil.

There's currently an effort underway to establish the region as a national park, but until that happens, the Tarkine remains vulnerable.

Tongass National Forest — Alaska Panhandle, U.S.

Tongass National Forest, Alaska
Tongass National Forest, Alaska (Photo: Lee Prince/Shutterstock)

Spread out across 17 million acres in Southeast Alaska, the Tongass is the country's largest national forest. Only about 10 million acres of this immense chunk of land is forested, and of that number, only about 5 million acres are classified as "productive old-growth." While logging remains a looming threat to the Tongass, there have been major gains over the past few decades to restrict road-building and timber industry access throughout the forest.