The World’s Countries, Ranked By Tree Wealth

Friends and longtime readers are no doubt well away of my fondness for international rankings of all kinds. So it is nice to spice up the usual indexes of social, economic, or political performance and instead compare countries by the interesting new metric of tree wealth.

A team of researchers led by Thomas Crowther of Yale University recently published a study in Nature that looks at where the world’s over 3 trillion trees are located, and how this compares with a country’s geographic size, population, and more.

This might seem like an odd attribute to look at — perhaps suited for nothing more than an amusing fun fact — but as the Washington Post points out, trees are an often vital natural resource well worth studying and preserving.

[Having] lots of trees in a country provides a huge host of benefits — trees are both a natural resource and an asset to humans. They filter water, combat air pollution, sequester huge amounts of carbon that would otherwise reside in the atmosphere, and even, it appears, contribute to human psychological and health benefits. Indeed, large parts of the world population depend on forests for food.

And then, there’s just the emotional connection to nature. “I think people inherently value trees”, said Clara Rowe, a co-author of the study and a recent graduate of the Yale School of Forestry and Environmental Studies, by e-mail. “In the days since our study was published, we’ve heard from individuals all over the world who are concerned about forest resources in their countries.”

Amid widespread environmental degradation and worsening global climate change, such scientific and public interest in the health and abundance of trees is well founded. Where they naturally exist, they are a barometer for the health, vitality, and sustainability of the local ecosystem. So those nations that have managed to preserve as many trees as possible have much to gain, as well as a lot to offer the world at large. Tree wealth is an apt description.

Starting with the most basic measurement, here are the countries with absolute most trees. (The researchers note that these estimates are more accurate with larger countries and less so with smaller ones.)

Total Tree Count

Source: Nature / Washington Post

You can find an interactive version in the Post article, which allows you to select an individual country to see its estimated number of trees.

As one can plainly see, the countries with the most trees in total are, unsurprisingly, the largest ones.

Based on this approach, the world’s overall tree leader is clearly Russia, with 642 billion total trees, followed by Canada with 318 billion and Brazil with 302 billion. The United States is actually fourth overall in this ranking, with 228 billion trees. Other countries with over 100 billion trees include China, with 140 billion and the Democratic Republic of the Congo, with 101 billion. Indonesia comes in 7th, with 81 billion, and Australia 8th, with 77 billion.

Adjusting for territorial size, the next measurement looks at tree density, e.g., the number of trees within a square kilometer (roughly equal to a little over a third of a square mile). 2015-09-16 14-20-03

Source: Nature / Washington Post

The difference is dramatic: countries with lots of trees in absolute numbers rank low once you adjust for size. Naturally, this applies most strongly to drier countries, such as the desert nations of Saudi Arabia and Qatar, each with just 1 tree per square kilometer.

Relatively large countries like Finland, Sweden, Bolivia, and Indonesia still fare pretty well, as do smaller countries like Gabon, Laos, New Zealand, and Slovenia. As the researchers note in the study:

…in “northern latitudes, limited temperature and moisture lead to the establishment of stress-tolerant coniferous tree species that can reach the highest densities on Earth”. There is more total forest in the tropics, they found, but it isn’t as dense. So the type of forest that a country fosters has a big influence on this metric.

Next up is the number of trees per person. One could imagine that countries with large populations would have a lot less tree wealth to go around, especially with the subsequently high need for space, shelter, and farmland.

Trees Per Person

Source: Nature / Washington Post

[Once] again … vast northern countries like Russia and Canada are surprisingly “tree rich”, with thousands of trees per resident. There are a whopping 8,953 trees per person in Canada. But tropical countries of the southern hemisphere can also hold their own. Here, Bolivia (5,465 trees per person), Gabon (8,131), and the Central African Republic (5,152) also fared quite well.

By contrast, desert countries once again were quite low – Egypt was  estimated to have only about one tree per person. The metric is also highly sensitive to population size, meaning that India, with a population of 1.27 billion and a tree population of only about 35 billion, had just 28 trees per person.

Very high tree-to-person numbers were clustered in the northeast of South America: Suriname had 15,279 trees per person, Guyana 14,692, and French Guiana a stunning 20,226. Of course, these countries all have populations under a million people.

So we have gone over the number of trees as they relate to size, density, and population. But what about wealth? Intuitively, fast-growing poorer countries would seem likelier to strip their forests clean, given the greater need for readily available farmland, fuel, and construction material. Most industrialized nations have moved on to other sources, or have the luxury of more efficient (and thus less land-intensive) agriculture; urban parks and tree planting are also a hallmark of greater wealth and development. Various reports and studies seem to bear this out, too.

Let the data do the talking.

Source: Nature / Washington Post

Source: Nature / Washington Post

Ultimately, the researchers concluded that “it was not clear that there was any meaningful difference overall”.

Rather, it was simply the case that one emerging country grouping, “Middle East, North Africa, Afghanistan and Pakistan” was quite low on trees — but then, that’s not surprising given the prevalence of desert in these countries. So it seems odd to relate this to economics, rather than simple geography. Simply put, some countries, due to their environments and climatic regimes, just can’t host as many trees as others.

“If you said to me, okay, the GDP per capita of Costa Rica is $8,000, I would have no way of telling you how many trees there are in Costa Rica or how dense those trees are”, said Yale’s Clara Rowe. She said that the most meaningful way of looking at the relationship between a country’s wealth and its tree resources would be to calculate a nation’s “forest potential” — how many trees it is actually capable of supporting — and then compare that with how many it actually has, which would then reflect how much the country has exploited those resources, as opposed to preserving them.

“That can really give us a better sense of what percentage of forest can be lost in every single country, and then maybe we can start relating that to things like GDP”, Rowe said. But the researchers haven’t done that analysis on a country-by-country level yet.

Studying “forest potential” would definitely be the next step. Granted, it is important to keep in mind that there is a big difference between having lots of trees and having lots of forest; a country’s cities might have plenty of trees in its parks, medians, and public spaces, but these would not support the sort of thriving ecosystem as an unspoiled forest would. While trees are important in their own right, for reasons specified earlier, they need to be in abundant number and left undisturbed to support certain wildlife. That would be a whole different sort of wealth to look into.

The Health Benefits of Watching Fish

IFLS reports on the first known study to research the psychological effect of observing marine life. It might seem like an oddly specific thing to look into, but given the long history of aquarium-keeping across civilizations, it makes sense to consider what value humans derive from the practice

Sure enough, British researchers from Plymouth University and the University of Exeter, in collboration with the National Marine Aquarium, found measurable benefits in physical and mental well being among test subjects following a bit of aquarium-gazing.  Continue reading

Where People First Started Eating Chickens

While chicken is the leading meat of choice among most Americans, and second only to pork globally, consuming them is actually a fairly recent practice in human history. Hence why the discovery of chicken bones that appeared to have been prepared for food was somewhat groundbreaking.

As NPR reports, the emergence of chickens as a food source seems to be marked by an over 2,000-year-old site in present-day Israel. Called Meresha, the former trade city presents a turning point in our relationship with the now universally-domesticated poultry. Continue reading

Less Than a Minute of Nature Can Boost Health

The Atlantic reports on yet another study confirming the benefits of exposure oneself to nature, even for literally a glimpse.

A nice walk through a city park can do wonders for a work-weary brain, reducing mental fatigue and improving attention. But if you’re trapped on the high floors of an office tower all day, you can’t exactly break for a long stroll and a picnic. Well, fear not. If you have a view of a nearby green space, like say a green roof, and even just a minute to spare, you can reap some of the same refreshing benefits of urban nature.

That’s the upshot of a new paper from an Australia-based research team set for publication in the Journal of Environmental Psychology. Their work has found that even taking just 40 seconds to focus on a view of nature can boost “multiple networks of attention”—sharpening your mind to handle the next task dealt by the work day. They call it a “micro-break,” and it turns out your brain loves it:

You can read the details and methodology of the study in the article, but it is certainly not the only research to confirm the importance of nature to human well-being:

The findings certainly fit with all that social science has found in recent years about the restorative power of nature. Whether it’s a walk through a park, a stand of trees out the window, or a mere desk plant, natural views give the working brain a breather—to varying degrees—by engaging our involuntary attention centers. The new conclusion that greenery might work its magic in mere minutes is an especially intriguing prospect in a fast-paced work world. And if green roof simulations were replaced with the real thing, the performance outcomes in the current study might even have been stronger.

I can certainly vouch for this by personal experience. From my regular bouts of anxiety and depression, to good old fashioned work-related stress, pausing for just a moment to focus on my desk plant, visit my garden, or take a stroll through a nearby park has done wonders.

I am glad to work just blocks away from a beautiful public park (and more glad that my job lets me take regular walk breaks). Since I have incorporated this practice into my daily routine, I have seen a notable decline in both the frequency and severity of stress, fatigue, and sadness (although other lifestyle and dietary changes have continued to that as well).

But a few minutes is all it takes to try this out and see the difference.

One-Sixth of Life Threatened With Extinction

From The Straits Times:

Climate change could drive up to a sixth of animals and plants on Earth to extinction unless governments cut rising greenhouse gas emissions, according to a US study published on Thursday.

Species in South America, Australia and New Zealand are most at risk, since many live in small areas or cannot easily move away to adapt to heatwaves, droughts, floods or rising seas, said the report in the journal Science.

The study averaged out 131 previous studies of climate change, whose projections of the number of species that could be lost to climate change ranged from zero to 54 per cent of species worldwide – too wide to be useful in designing conservation policies.

Overall, it found that one in six species could be driven to extinction if greenhouse gas emissions are unchecked and temperatures rise by 4.3 deg C above pre-industrial times by 2100, in line with one scenario from the UN Intergovernmental Panel on Climate Change (IPCC).

As another study reported in the The Washington Post found, large herbivores, which remain mostly in Africa, are especially vulnerable:

Large herbivores — elephants, hippos, rhinos and gorillas among them — are vanishing from the globe at a startling rate, with some 60 percent threatened with extinction, a team of scientists reports.

The situation is so dire, according to a new study, that it threatens an “empty landscape” in some ecosystems “across much of the planet Earth”. The authors were clear: This is a big problem — and it’s a problem with us, not them.

“Growing human populations, unsustainable hunting, high densities of livestock, and habitat loss have devastating consequences for large, long-lived, slow-breeding, and, therefore, vulnerable herbivore species”, reads “Collapse of the world’s largest herbivores” in Science Advances, a publication of the American Association for the Advancement of Science…

…Between 2002 and 2011 alone, the number of forest elephants in central Africa declined by 62 percent. Some 100,000 African elephants were poached between 2010 and 2012. And the western black rhinoceros in Africa was declared extinct in 2011.

“This slaughter is driven by the high retail price of rhinoceros horn, which exceeds, per unit weight, that of gold, diamonds, or cocaine”, according to the study. provides a chilling picture at what the world will look like one out of six species gone:

“This paper is only about extinction risk, which is the most extreme of the biotic risks of climate change,” he says. “But that’s also just the tip of the iceberg. We’re also seeing substantial changes in abundances and ranges. So even if we didn’t have a single extinction, we’d be looking at a substantial reorganization of biodiversity around the world. And that will have many effects, some detrimental to other species and human interests.”

Even so, extinction tends to grab the most attention — and often for good reason. “The world is more colorful place with this diversity of species,” he says. “And it’s hard to imagine a world where we’ve lost a significant portion of these species. You think about losing one in six species. It’s like telling an artist they can no longer paint in one color.”

Not to mention the practical everyday impacts. “Global biodiversity is really the foundation of our natural economy, our food security, and our health,” he adds. “These are species that are integrally interwoven into our economic and personal life. When you get to these high extinction risks, you’re talking about a dramatic effect on world.”

Global Spotlight: Socotra, Yemen

Socotra (also spelled Soqotra) is an archipelago of four islands in the Indian Ocean that is part of Yemen. Evidence of human settlement go back to antiquity, where the island served as a stopover for various trade routes that passed by. However, there are signs of a pre-human presence going back over a million years. Ancient inscriptions have been found written in everything from Aramaic and Greek, to pro-Arabic and ancient Indian scripts.

Today, only around 50,000 people live on Socotra, most of them eking out a living as subsistence farmers and fishers. A product of the area’s isolation, they continue to speak a nearly extinct language alongside their own distinct Arabic dialect.

Socotra’s long geographic isolation, combined with its unforgiving heat and dryness, have created a distinct and spectacular ecosystem comprised of flora and fauna found nowhere else in the world; nearly 700 species are unique to the area (only Hawaii, New Caledonia, and the Galapagos Islands surpass it in terms of sheer biodiversity). For this it has been recognized as a world heritage site and nicknamed the Jewel of the Arabian Sea. 

Among the most famous occupant is the dragon blood tree, so named for its crimson red sap, which was highly valued for centuries as a dye, medicine, glue, lipstick, and even breath-freshener. Because it was believed to be dragon’s blood — a fact that could not be unverified in ancient times given the island’s seclusion — the sap was also valued in alchemy, and even today many inhabitants of the island and nearby areas allegedly regard it as a miracle cure for all sorts of ailments.

Socotra, Yemen IV

Socotra continues to retain its centuries-long mystique and character, offering an often alien landscape that is found nowhere else in the world.

The Sixth Mass Extinction

The International Union for Conservation of Nature (IUCN), which compiles and manages the most extensive list of organisms, has determined that nearly 20,000 plant and animal species are at risk. Unsurprisingly, human activity — from direct ecosystem destruction to pollution — is the main culprit.

Even more distressing, the organization’s Red List of threatened and endangered species represents just a small fraction of the world’s total life: less than four percent of the roughly 1.7 million species known to exist have been evaluated, meaning many more could be on their way out — if not already extinct — without our knowledge.

The following infographics from the New York Times paint a very grim picture:

Read more about this dire situation here. Not only is the loss of biodiversity problematic in itself, but it bodes ill for the future of our species, given the vital role that ecosystems play in everything from climate regulation to food supply.

Keep orcas in the wild, not in aquaria


I wholeheartedly agree.

Originally posted on Why Evolution Is True:

Blackfish is a 2013 documentary movie about captive orcas (killer whales) at SeaWorld in Orlando, Florida. It centers on Tilikum, the infamous orca who killed three people (including two trainers) and is still at SeaWorld.  The documentary, directed by Gabriela Cowperthwaite, premiered at Sundance in Utah, and has received a lot of critical acclaim. It gets a 97% from the critics on the Rotten Tomatoes site, and Wikipedia says this:

Critical reception for the documentary has been mostly positive, with the Deseret News calling it “a gripping example of documentary filmmaking at its finest”. Twitch Film and The Hollywood Reporter both praised Blackfish, with both review sites arguing that the film gave “a persuasive case against keeping the species – and by extension any wild animal – in captivity for the purposes of human entertainment”. Film School Rejects gave the documentary a rating of B-, writing that…

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A snake mimics a spider

Originally posted on Why Evolution Is True:

If you like evolution and natural history, you should already be reading Ed Yong’s terrific site Not Exactly Rocket Science at National Geographic. In his short post “This snake has a tail that looks like a spider,” he describes a remarkable and newly found type of mimicry.

The snake is, appropriately, the spider-tailed viper (Pseudocerastes urarachnoides), first described formally only 7 years ago from Iran.  It was known since the sixties, but the one specimen’s tail was dismissed as a tumor or deformity. We now know from other specimens that this is indeed a species-specific trait. As Yong notes:

The tail is bizarre. If you saw a close-up photo of it, you’d struggle to believe that there was a snake at the other end. There’s a large orange or grey bulb at the tip, and the scales just before that are bizarrely long and thin…

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