It is a couple days after the start of spring on a windy afternoon in Frazer Forest and Sarah Adloo is walking among the trees. The 39-acre forest in the Druid Hills neighborhood of Atlanta features native tree species. Adloo pauses on a trail not far away from a large northern red oak with its distinctive bark — cracked and uneven with dull ridges running up and down its tall trunk.

“We also have a lot of younger beech trees around us that have this silvery gray finish to them,” Adloo said. “They hang on to their leaves throughout the winter and then drop them much later in the spring."

Adloo is the co-executive director of the Old-Growth Forest Network, an organization working to preserve and expand areas of old-growth forests in a growing number of states across the country. Frazer Forest is one of more than a dozen pockets of green in the Atlanta metro area recognized as old-growth forest by OGFN. Adloo said the network of old growth in Atlanta makes it unique among U.S. urban centers.

"We're known as the 'city in the forest,' and we do have pockets of high-quality old-growth forest throughout the city," Adloo said. "But we also lose a lot of our forest coverage every day. So we have to really make sure that those pockets that serve neighborhoods really well are protected through parks, easements and other methods."

Old-growth forests are vital resources and can do things younger forests cannot, she said, such as harbor wider biodiversity. Older, more mature forests also play an important part in the fight against human-caused climate change.

But there are few old-growth forests left in Georgia and across the United States. A 2008 report by the National Commission on Science for Sustainable Forestry estimated only about half a percent of all forest land in the Southeast was old-growth forest.

Just last week, President Joe Biden signed an executive order to inventory and protect old-growth forests nationwide. The order gives the Department of the Interior and Department of Agriculture a year to take stock of the amount of old-growth in the U.S. After collecting the data, the agencies must come up with new policies to manage and conserve these wooded areas.

The move comes after a call from more than 70 environmental organizations across the country, including the Old-Growth Forest Network, Sierra Club and the Southern Environmental Law Center, for the federal government to take action to protect old-growth forest on federal lands. 

Biden’s order requires the federal agencies to come up with a definition for old-growth forests. That will be harder than it sounds. 

There is no consensus on what defines an old-growth forest. According to the U.S. Department of Agriculture, ecologists began using the term in the 1970s to describe forests at least 150 years old that had developed a complex ecosystem of living and dead trees, and diverse groups of plants, animals and fungi.

J.D. McCrary, Executive Director of Georgia Forest Watch, said old-growth looks different across Georgia’s diverse forests. The qualities found in aged longleaf pine stands near the coast are different from the qualities in aged poplar forests in North Georgia.

“The later stages of forest development typically differ from earlier stages in a variety of characteristics,” McCrary said. “Including tree size, accumulation of large dead, woody material, number of canopy layers, species composition and ecosystem function.”

Regardless of the exact definition, McCary said, older forests are valuable and hard to come by.

“We're doing everything we can to keep the old-growth forests that we have,” McCrary said, “and allow younger forests to grow back into old-growth.”

Eli Dickerson, the lead ecologist at the Fernbank Museum of Natural History in Atlanta, agreed the definition of old-growth is not clear cut. 

“But the most important aspect is you've got living trees, you've got dead trees, you've got old trees, you've got young trees, you've got standing dead trees called snags that provide habitat, you've got dead wood on the ground and you've got a plethora of animal diversity and fungal diversity and everything in between.”

Dead trees are an important part of these ecosystems, Dickerson said, and play a vital role in the fight against climate change. As Eli walks along a path in the 65-acres of old-growth forest outside the Fernbank Museum on what was once Muscogee Nation land, he comes across a big dead beech tree that fell in the previous couple years. 

“What I'm seeing is the trunk has decayed and it's got about a third or half of its bark gone,” Dickerson said. “I see lots of fungal growth, the root ball that tipped up. I've counted as many as 12 or 15 different plant species just growing on that one little root ball."

So while some of the dead beech tree’s carbon returns to the atmosphere, much of it remains in the forest, helping other plants and animals live and grow — and sequestering more carbon from the air. 

The size and age of trees are not the most important part of old-growth ecosystems, experts say. Instead, it is the complex and layered network of relationships between tree, soil, fungi, plant and animal that continue after an individual tree has died. Trees grow old, die and remain fallen as the cycle begins over again.

The people who love these important resources say action is needed to preserve and expand them.

Adloo said public awareness is key. Often, by the time community groups seek help from the Old-Growth Forest Network to protect a local forest on public land, it is too late to intervene. 

"There's very little we can do unless you get in ahead of that process and really pay attention to that forest and make sure that you are making your voice heard that that should be a protected area," Adloo said.

Preservation efforts have seen success where volunteers come together to get local officials set aside public land in forest management plans. 

However, nearly 90% of Georgia forests are on private land, according to the U.S. Department of Agriculture. So the Old-Growth Forest Network urges private landowners to set aside a portion of their forested land to remain undeveloped. 

"Even letting a small portion of those trees grow to their full ecological potential and let that forest become robust and complex would do wonders for the state of Georgia receiving old-growth benefits," Adloo said. "And even landowner can really receive them individually."