Nature Heals

by American Forests

By Tacy Lambiase

Credit: Amrit Patel/Flickr

Credit: Amrit Patel/Flickr

Sometimes, bad things happen in our lives that can damage us emotionally, physically and mentally. But we’ve known for a while that the presence of nature in our lives can help us heal and overcome obstacles. Spending time in the great outdoors can sharpen our mental capabilities, enhance our creativity abilities and lower our blood pressure and heart rate. Even people recovering from physical injuries heal faster when they have access to nature or even just the ability to look at trees out of their windows.

“As a species that exists within nature, we are incredibly affected by its absence and presence,” writes Neil Chambers on “Yet, we function in cities and buildings that largely lack a connection to the environment. … The act of simply reconnecting people to the natural elements brings about faster recovery rates, reduced stress and eased symptoms of physical and mental disorders.”

But nature can also comfort people who are experiencing emotional turmoil, such as grieving someone’s death. Coping with the loss of a loved one can be an exhausting and emotionally draining process. When tragedies occur, humans react with emotions ranging from shock and anger to sadness and lasting depression. While mourning can throw us into a state of prolonged grief and despair, the natural world can help us to regain a sense of peace and inner calm.

“Being in nature one becomes aware of the infinite circle of life,” Dr. Kirsti A. Dyer tells Mother Nature Network. “There is evidence of decay, destruction and death; there are also examples of rejuvenation, restoration and renewal. The never-ending cycle of birth, life, death and rebirth can put life and death into perspective and impart a sense of constancy after experiencing a life changing loss or a death.”

Connecting with nature can help people move beyond grief and towards emotional and mental well-being. Taking walks in a park, working in a garden or hiking along a wooded trail are all activities that can motivate individuals to keep moving and stay active in the wake of a personal tragedy.

Perhaps John Muir, one of America’s most active conservationists, knew the emotional benefits of nature best when he advised:

“Climb the mountains and get their good tidings. Nature’s peace will flow into you as sunshine flows into trees. The winds will blow their own freshness into you and the storms their energy, while cares will drop off like autumn leaves.”

Quiet, Please. The Tree is Speaking.

by Susan Laszewski
Artist Alex Metcalf’s Tree Listening Project, shown here in 2009, allows visitors to listen to the sounds of trees drawing water from their roots. Now, scientists are learning to discern which of these sounds are indicative of drought conditions. Credit: Tom Grinsted.

Artist Alex Metcalf’s Tree Listening Project, shown here in 2009, allows visitors to listen to the sounds of trees drawing water from their roots. Now, scientists are learning to discern which of these sounds are indicative of drought conditions. Credit: Tom Grinsted.

As sci-fi as it sounds, the news that trees make noise beyond the human range of hearing — and that some of these noises communicate important messages to other organisms — is not new. Studies have shown, for example, that some plants release pollen in response to bees’ buzzing.

But could trees be saying anything to us? Okay, they may not be speaking to us directly, but new research suggests that, if we learn how to listen, we could gain valuable information on how to protect trees by eavesdropping on them.

It’s long been known that cavitations — air bubbles that block the flow of water throughout the tree — make a sound that can be heard with a microphone. If too many of these cavitations occur, such as we might see in drought conditions, a tree can die.

The problem is that the sounds of cavitations, among other tree activity, are outside our usual range of hearing and can only be heard with the proper equipment. Then, the question of how to tell which sounds are indicative of cavitations — and therefore early warning signs of drought stress — was a bit of a doozy.

Until now. A team of scientists from Grenoble University, Saint-Martin-d’Hères in France, led by physicist Alexandre Ponomarenko, presented a study at last month’s meeting of the American Physical Society that seems to hold the promise of a day when what is now lost in translation could be found. Using a gel capsule-like device developed by Cornell University’s Dr. Abraham Stroock, the scientists were able to take a peek inside a simulated tree and observe the cavitations and other activity at the same time sounds were being recording. Cross referencing the visual and audio data, they were able to distinguish the sounds that corresponded with cavitations from other sounds, such as fractures in the wood.

Artist Alex Metcalf’s Tree Listening Project, shown here in 2009, allows visitors to listen to the sounds of trees drawing water from their roots. Now, scientists are learning to discern which of these sounds are indicative of drought conditions. Credit: Tom Grinsted.

Artist Alex Metcalf’s Tree Listening Project, shown here in 2009, allows visitors to listen to the sounds of trees drawing water from their roots. Now, scientists are learning to discern which of these sounds are indicative of drought conditions. Credit: Tom Grinsted.

By learning to recognize these sounds, we would be able to help trees suffering from drought before it became too late. Dr. Ponomarenko tells National Geographic, “With this experiment we start to understand the origin of acoustic events in trees.” This research could one day lead to handheld devices that allow us to listen to trees or even to devices that stay with the tree, monitoring it fulltime for signs of drought. A sort of walkie-talkie from the tree to us, letting us know when action is needed.

But don’t start tuning your radio for tree signals yet. It will take a lot of hard work and research to apply what was learned from a piece of wood in a lab to a complex, living tree. Nonetheless, the future looks a little less dry.

Wanted: Wildfire

by American Forests

By Michelle Werts

Black-backed woodpecker

Black-backed woodpecker. Credit: Mike Laycock/National Park Service

Wildfires are one of the most prolific forces affecting our nation’s forests. They are often intense and unpredictable — and are only likely to become more so in the coming decades thanks to climate change. They threaten homes and communities, which is why American Forests supports projects like the U.S. Forest Service’s Collaborative Forest Landscape Restoration program, designed to reduce wildfire risk in local communities. They can be scary things, but for many species, they aren’t scary at all. Instead, they are essential for life.

The black-backed woodpecker is one such species because it likes beetles, and do you know what beetles like? Blackened forests. Why? Because fire-damaged trees are easier for wood boring, of course. Unfortunately for the black-backed woodpecker, though, in 1936, the U.S. embarked on a fire suppression policy that would last for decades. Low-intensity burns were squelched before they could get started and the woodpecker’s preferred fire-burned habitat began to disappear — and so did the woodpecker. Compounding matters were salvage efforts in post-fire landscapes, where damaged wood was removed for logging purposes instead of being allowed to regenerate naturally, which again, removed habitat and food source for burn-loving species that actually moves its habitat to coincide with burn areas.

Last spring, conservation groups petitioned to have the black-backed woodpecker added to the Endangered Species List, and American Forests joined the effort through a letter in our Action Center, which allowed our members to speak out and encourage management of post-fire landscapes that accounts for species that need burned forests to survive. Earlier this month, it was revealed that those voices were heard, as the U.S. Fish and Wildlife Service announced that it would consider the species for federal protection and was opening a 60-day information-gathering and comment period.

Whitebark pine

Whitebark pine. Credit: Donald Owen/California Department of Forestry and Fire Protection/

But what about other fire-loving species? American Forests has its conservation sights set on protecting and restoring another: whitebark pine. Growing in the high-elevation forests of the Mountain West, whitebark pine is considered a keystone and foundation species. It earns this status by providing food for a variety of wildlife and serving as shelter for hundreds of plant and animals species, protecting them from harsh weather on the mountaintops. But while it’s looking out for others, who’s looking out for it?

Decades of fire suppression mean that the whitebark’s forests are more densely populated than the species would like. Being a pioneer species (or one of the first to populate an ecosystem), it doesn’t do well with competition, and its seeds struggle to survive. Plus, a dense canopy results in less sunshine, and the whitebark loves to — no, needs to — soak up the rays to flourish. Low-intensity fires would help clear some of the competition and open up the forest canopy to some sunlight for the whitebark, which needs all the help it can get since it’s also facing threats from an unprecedented outbreak of mountain pine beetles and white pine blister rust.

Mountain pine beetle

Mountain pine beetle. Credit: U.S. Forest Service Region 2 Rocky Mountain Region Archive/

The American Forests Endangered Western Forests initiative is providing some of that help. We’re creating healthy planting sites for whitebark pine, planting disease-resistant seedlings, reducing the amount of competing species to help with natural regeneration and so much more.

You know who else might help the whitebark? The black-backed woodpecker. Remember? It finds beetles tasty, including mountain pine beetles. So if we help one, we might help the other. Welcome to the glorious circle of life.


The Value of Conservation

by American Forests

By Josh DeLacey

The outdoors makes money — even more money than we thought it did two years ago.

Commissioned by the National Fish and Wildlife Foundation, Southwick Associates, Inc., recently released a study of The Combined Value of Outdoor Recreation, Natural Resource Conservation and Historic Preservation, which found that those three areas annually generate at least $1.7 trillion in economic activity, support 12.8 million jobs and bring in $211 billion in tax revenue. As the report notes, “this sector of the U.S. economy is larger than the U.S. auto and pharmaceutical industries combined.”

Tree plantings create jobs and effects throughout the economy.

Tree plantings create jobs and effects throughout the economy. Credit: Tim Redpath

Southwick Associates, a group devoted to exploring the monetary issues related to environment, natural resources and outdoor recreation, conducted a similar study back in 2011. However, due to limited data, it could only present a “minimum estimate,” and it put the annual economic activity that resulted from outdoor recreation, conservation and historic preservation at $1.06 trillion, jobs at 9.4 million and tax revenue at $107 billion —very impressive numbers already. Government agencies, nonprofits and advocates cited the report as a clear reason why conservation spending is important and beneficial.

But the National Fish and Wildlife Foundation wanted more accurate information. So Southwick Associates did a deeper investigation and prepared another report. The difference between the 2011 and 2013 findings is huge: a 70 percent increase in economic activity, a 26 percent increase in jobs and a 97 percent increase in tax revenue.

Part of the study also focused on the impacts of conservation alone. Annual U.S. conservation spending totals $38.8 billion, but it produces $93.2 billion of economic output throughout the economy — 2.4 times more than what is put in. This output takes the form of more than 660,500 jobs, $41.6 billion in income and a $59.7 billion contribution to national GDP.

You can read the full version of the conservation report, but here is an explanation of some of its most interesting findings:

  • Of the $38.8 billion spent annually on conservation, 60 percent comes from the federal government. State governments account for 25 percent, the private sector makes up 11 percent and local governments contribute the remaining 4 percent. Most of the private sector spending passes through nonprofits such as American Forests.
  • The report calculates the direct economic contributions of conservation spending, as well as its indirect contributions. The direct effects of conservation spending only look at the immediate results: the jobs, income and tax revenues that happen right away, without accounting for any multiplier effects. Even so, conservation spending directly provides $23.1 billion in income, 277,000 jobs and $5.6 billion in taxes. Not nearly as impressive as $93.2 trillion, but as any economist will tell you, spending is not limited to its direct contributions.
  • The study also measures indirect contributions of conservation spending. Indirect contributions are defined as “how sales in one industry impact other industries.” For example, when American Forests funds a tree planting, we also impact the transportation industry (the planters have to drive to the planting site), real estate industry (we have to rent our office space), household spending (everyone who gets paid spends part of that money, putting it to further use in the economy) and other industries. Southwick uses the IMPLAN model to calculate these indirect benefits, which is how they get the total value of $93.2 billion.
  • The report breaks up data by state, showing a wide range of conservation spending. California leads the pack with $4.3 billion, and Rhode Island picks up the rear with $108 million. In all but three states (South Dakota, Texas and Wyoming), the money spent produces more money in resulting economic activity.

The Southwick Report shows that nature is valuable — for more than just its ecological benefits. With conservation prompting $93.2 billion in economic activity and outdoor recreation and historic preservation generating more than $1.6 trillion more, there is a clear financial motive for protecting the environment.

Striving for Justice

by Amanda Tai
California protesters. Credit: uusc4all/Flickr

California clean water protesters. Credit: uusc4all/Flickr

Earlier in the month, I attended the National Environmental Justice Conference (NEJC) in Washington, D.C. Over the span of the conference, I was able to hear from people from all over the country who are working on environmental justice issues. Some of the speakers had been working on environmental justice for half a century! A lot has changed since then, but there’s still a lot of progress to be made.

Let’s take a look back at where we were 50 years ago. The Civil Rights Act of 1964 prohibited the use of federal funds to discriminate on the basis of color, race and national origin. This served as a powerful base for the environmental justice movement. Protests filled the 1960s, as minority populations began to take a stand against environmental injustices they were experiencing. These injustices ranged from migrant farm workers being exposed to DDT to toxic dumps in close proximity to communities.

In 1994, President Clinton issued Executive Order 12898, building off of the Civil Rights Act of 1964, to bring a social and civil rights approach to environmental issues. While these policies incorporate an environmental justice consciousness at the federal level, there is still a lot of work to do on the ground for underserved minority communities that continue to bear the burden of environmental hazards. Efforts like capacity-building, environmental education and technical training are some of the ways to help these communities.

At Sam Houston National Forest, the Latino Legacy Program is helping to develop picnic areas, boat access points, swimming areas and many other resources for the Hispanic community, which is the majority of the forest’s visitors. The Latino Legacy Program also has an education and outreach team, called “Los Amigos del Bosque” (Friends of the Forest), and “Boqsue Movil” (Forest Mobile) that provides bilingual information on conservation to engage Latino youth and communities.

Credit: Nongbri Family Pix/Flickr

By sharing photos and stories on Discover the Forest’s Facebook page, minority families are building a community of outdoor enthusiasts. Credit: Nongbri Family Pix/Flickr

The U.S. Forest Service is also developing its Discover the Forest Campaign to reach minority audiences (Descubre el Bosque). By translating educational material and creating more targeted ads, the Discover the Forest Campaign hopes to inspire all populations to get outside.

At the NEJC, I learned the importance of presenting tools and information in a variety of ways since different audiences may have different priorities and values. There also seems to be an underlying value of community and family across all audiences, which will be a key to building the next generation of conservationists.

A Pesky (and Costly) Problem

by American Forests

By Tacy Lambiase

Think you know the impact that invasive pests can have on our ecosystems and pocketbooks? You might want to think again. Every year, pesky insects and pathogens cost our nation billions of dollars in damaged crops and forestlands.

U.S. Department of Agriculture entomologists inspect orange trees for Asian citrus psyllids.

U.S. Department of Agriculture entomologists inspect orange trees for Asian citrus psyllids. Credit: USDA

Earlier this month, the U.S. Department of Agriculture (USDA) released a list of the top 15 pests that pose the greatest threats to our agricultural system and trees. Some of the insects on the list are familiar beasts: the emerald ash borer (EAB), which has been devastating ash trees across the Midwest, and the Asian longhorned beetle (ALB), a pest that destroys maple trees and other hardwood species in the Northeast.

Although the state of New Jersey recently eradicated ALB, the species has already cost the United States millions of dollars and has severely altered tree cover in states like Massachusetts. “It’s been dramatic,” Chris Martin, a Connecticut state forester, tells USA Today. “You used to have tree-lined streets, and now these neighborhoods are just devoid of trees.”

Other notorious pests on the list eat their way through agricultural production, ruining food grown in orchards and farms across the country. For example, the Asian citrus psyllid, an insect that carries Citrus Greening Disease, has single handedly cost orange and grapefruit growers in Florida nearly $4.5 billion. Two species found in Hawaii, Oriental and Mediterranean fruit flies, feast on hundreds of different fruits, vegetables and nuts. The effect of these flies is similar to that of the Asian citrus psyllid: Produce and crops are destroyed and rendered unfit for consumption.

With the spread of these insects, the U.S. may start cracking down on travelers and campers who can unknowingly spread these pests. Many campgrounds already prohibit campers from bringing in firewood from other places since insects and wood borers could be brought to the area as larvae inside of the wood. Other parks don’t allow visitors to take firewood outside of their borders, especially in regions that have already been infested with insects like EAB and ALB.

Other countries are battling the same invasive pests as the U.S.. A sign posted in Toronto, Ontario, is part of Canada’s efforts to contain an infestation of Asian long-horned beetles.

Other countries are battling the same invasive pests as the U.S.. A sign posted in Toronto, Ontario, is part of Canada’s efforts to contain an infestation of Asian long-horned beetles. Credit: GTD Aquitaine/Wikimedia Commons

“We need to get Americans to start thinking about how these pests are moving around the country,” says Scott Pfister, the director of the pest management department at the USDA’s plant protection and quarantine division, to USA Today. “April’s the time of year when people start to go camping and hiking and work in their gardens, so it’s a very appropriate time to address this national problem.”

Although some people may resist firewood restrictions, the USDA hopes to spread awareness and understanding about the need to control these pests and where they spread. The USDA has also declared April to be Invasive Plant Pest and Disease Awareness Month, drawing attention to the negative consequences of invasive species and pests.

Want to learn more about these pests and how you can help minimize their impacts on forests and crops? Visit the USDA’s website and

A Long-Expected Budget

by American Forests

By Josh DeLacey

President Obama released his Fiscal Year 2014 budget recommendations on Wednesday, and with only a few disappointments, the budget shows dedicated support for forestland health and federal conservation programs.

The White House

The president’s FY2014 budget makes forest health a priority. Credit: Beth Jusino

To keep sequester cuts from inflicting more damage, the president’s budget is based on FY2012 funding levels, a decision American Forests has advocated in favor of. The sequester put FY2013 funding too low for adequate conservation, and we have seen the consequences in national park closures and underfunded wildfire management. Moving forward, responsible conservation requires — at a minimum — a return to full FY2012 funding levels, and we are happy to see the administration recognize this need.

Specifically, the budget recommends fully funding the U.S. Forest Service’s Collaborative Forest Landscape Restoration program (CFLR), which is restoring millions of acres of forestland across 23 project sites. As a member of the CFLR Coalition’s steering committee, American Forests is especially pleased that this bipartisan, community-based program has the administration’s support. The president’s budget also requests to restore pre-sequester funding for the Bureau of Land Management’s (BLM) Public Domain Forest Management, another important program.

But the president’s budget does more than just restore past funding levels: It also requests increased support for some of the government’s most vital conservation programs across federal agencies. For instance, the administration wants to increase funding for the National Wildlife Refuge System, which American Forests has worked closely with through various Global ReLeaf projects. Our most significant partnership is in the Lower Rio Grande Valley, one of North America’s most biologically diverse areas, where we have helped plant more than 1.5 million trees in the last 15 years. Other key programs whose funding the administration wants to increase include the Land and Water Conservation Fund, the national park system and the BLM’s national monuments and conservation areas.

Additionally, the president’s budget requests $10 million to establish the Urban Parks and Recreation Fund, a resource that American Forests is very excited about, as it would expand the environmental, social and economic value of urban forests. More than 84 percent of the U.S. population lives in urban areas, and they all stand to benefit from an increased focus on greening cities and suburbs.

Despite its good points, though, the president’s budget is not perfect. It decreases funding for the Urban and Community Forestry program by $6 million, limiting the technical, financial and educational assistance that the program offers to thousands of communities throughout the U.S. The National Recreation and Preservation program and the Recreation, Heritage and Wilderness program also face budget reductions.

But aside from those disappointments, American Forests is very pleased with the president’s budget. However, this budget is not set in stone. Next, in the coming months, Congress will examine it amid various other input to determine the appropriation funding levels for FY2014. But with the president’s budget restoring FY2012 funding levels for conservation, the prognosis is very promising. The administration has clearly indicated that forest health and conservation are priorities that deserve increased support.

This is Your Brain on Nature

by Susan Laszewski
A walk in the park

A walk in the park. Credit: Vincent Brassine

It’s not news that time in the great outdoors is good for your brain. We’ve written before about how exposure to nature is good for creative problem solving and mental health.

But how can we determine how much of this relationship is causal when there could be other reasons for correlation? Well, a new study released from researchers at Heriot-Watt University in Edinburgh and the University of Edinburgh published in the British Journal of Science has begun answering that question with some pretty high-tech tools.

The 12 study participants were given portable electroencephalograms (EEGs) called Emotiv EPOC to wear under hats against their scalps. The EEGs measured brain waves and sent data wirelessly to a laptop in the participant’s backpack. And here I thought Google glasses sounded high-tech! The participants were then sent on a mile-and-a-half stroll through three neighborhoods — a quiet shopping district, a park and a busy business district.

Analyzing their brain waves for patterns associated with short-term excitement, frustration, engagement, long-term excitement (mental arousal) and meditation, the researchers found that walking through the park eased participants’ brain fatigue. While they maintained attention to their surroundings, they also were able to reflect, unlike the heightened mental arousal that they experienced on the busy streets.

While a study of 12 participants doesn’t provide a large pool of data, the use of the new portable EEGs may open up a whole new world of studying nature’s effect on the brain in real-time. It certainly adds to the growing body of data telling us that planting and maintaining urban forests makes for a happier, healthier city and happier, healthier people.

Big Tree Madness Recap

by Loose Leaf Contributor
The "Prickly and Persistent" Ozark Chinkapin of Missouri won the title of "Ultimate Big Tree."

The “Prickly and Persistent” Ozark Chinkapin of Missouri won the title of “Ultimate Big Tree.”

What a win for the Midwest! Not only did the Louisville Cardinals take home the crown in last night’s NCAA championship, but the title of “Ultimate Big Tree” also went to a Midwestern tree in the Big Tree Madness final. Congratulations to Missouri’s “Prickly and Persistent” Ozark chinkapin!

Many may look at the champion and think, “It’s not that big. There are giant sequoias and southern live oaks that dwarf that tree.” But, remember, size is relative. All Big Tree Madness contenders are national champion trees — the largest known of their species in the country. Even the Texas redbud of Connecticut, which was eliminated in the first round, is a giant among its own kind — a “tiny titan” as they’re respectfully classified on the National Register of Big Trees.

Even so, the size of the Ultimate Big Tree becomes impressive when you take into account that the Ozark chinkapin is a member of the chestnut family, susceptible to the dreaded chestnut blight and, consequently, a species of conservation concern. Maybe that’s part of why it means so much to the legions of fans who came out to vote. Not only is the wood of this amazing tree rot-resistant, it proved itself resistant to defeat as well.

Perhaps the biggest upset of the tournament was the western redcedar’s fourth quarter defeat by the “Brave Giant” of Hawaii — the Acacia koa. Coming from a state known for its old-growth forest, Washington’s western redcedar was an early favorite to win, but the Brave Giant’s fans mobilized to crush the competition and went on to take their tree all the way to the Final Four.

The Acacia koa is the largest native tree species on an island that struggles with keeping invasives at bay. More than half of Hawaii’s original forests have been lost, largely due to invasives, so it’s no wonder that the “Brave Giant” would be an important symbol of pride in Hawaiian native forests. [Editor’s preview: The Spring/Summer 2013 issue of American Forests, which is being released next month, features an article on Hawaii’s delicate ecosystem and the struggle against invasives.]

But, as they say, everything is bigger in Texas, and in the Final Four, that included the “Mighty” Montezuma baldcypress’ fan base. The Montezuma baldcypress brought the koa’s run to an end, before facing its own defeat in the final.

You can review the entire bracket on our Big Tree page.

What’s next for Big Trees?

There are more than 780 national champions currently listed onthe National Register of Big Trees, so if your favorite big tree didn’t make it into the tournament, it doesn’t mean it’s not a national champion. Search the register, and if you still don’t see your favorite tree, stay tuned. The Spring 2013 release of the register is coming April 26th. Champions will rise, and reigning champs will be dethroned. Some new species may even see their first champion crowned. And, yes, we may mourn some fallen giants, as all life must eventually come to end. If you enjoyed Big Tree Madness, then hold on to your seats: The big tree fun is just getting started.

Under the Sea

by American Forests

By Michelle Werts

Green sea turtle

Green sea turtle. Credit: puuikibeach/Flickr

You know that old expression about “work following you home”? Well, last week, I had work following me on vacation. No, I wasn’t checking emails while visiting the Caribbean, but I did find myself reflecting on topics that are often discussed around the halls of American Forests and here on Loose Leaf, such as:

  • Rainforest deforestation – The island of St. Lucia used to be more than 80 percent rainforest, but those forests have been reduced to less than 45 percent due to past agricultural practices.
  • Endangered species – A snorkeling trip had me spying on threatened green sea turtles living in a protected bay and cove near St. Thomas, a U.S. territory.

And upon my return to work this morning, I found that the Caribbean had followed me home, as a study published yesterday in Nature Geoscience reveals how air pollution —something we normally discuss in the realm of how it affects human health, how it is impacting climate change, how forests help filter it — is affecting an unlikely species: coral in the Caribbean.

Reef off St. Croix, U.S. Virgin Islands

Reef off St. Croix, U.S. Virgin Islands. Credit: NOAA CCMA Biogeography Team

A team of climate scientists and coral ecologists studied coral growth rates in the western Caribbean between 1880 and 2000, using previously published data, and discovered that while coral may live under the sea, the atmosphere plays a big role in its growth.

In a release about the study, Dr. Paul Halloran explains that “particulate pollution or ‘aerosols’ reflect incoming sunlight and make clouds brighter. This can reduce the light available for coral photosynthesis, as well as the temperature of surrounding waters. Together these factors are shown to slow down coral growth.” The study shows that in the early 1900s, slower coral growth rates were a result of volcanic activity, as aerosol emissions clouded the atmosphere, but by the late 1900s, aerosol emissions slowing coral growth could be attributed to industrialization.

Coral reefs support a fourth of the world’s oceanic species, and the researchers behind this new study hope it will lead to more understanding about how climate change and regional industrialization may affect coral habitats.