Being Surrounded By Greenery Can Be Good for Your Heart

iStock.com/Givaga
iStock.com/Givaga

Living in a place with a little greenery is good for your health in more ways than one. Recent research has found that people perceive their health status as significantly better if they live around trees, and for good reason—in addition to helping you chill out, exposure to lots of green vegetation may be good for your cardiovascular health, as Cardiovascular Business reports.

A new study in the Journal of the American Heart Association suggests that living in green areas is correlated with certain biomarkers for cardiovascular health. Scientists analyzed blood and urine samples from 408 people at a cardiology clinic, then compared the results to satellite-derived data on the levels of greenery around those patients’ homes (using 820-foot and half-mile radiuses).

Adjusting for age, sex, race, smoking status, “neighborhood deprivation” and other factors known to be linked heart disease rates, the researchers found that living in a green area was correlated with several markers of a healthy heart. Blood and urine samples from those participants who lived in green neighborhoods showed lower levels of sympathetic activation—the body’s automatic fight-or-flight response, which raises the heart rate and is involved in heart failure. Those participants also had reduced oxidative stress—an imbalance between free radicals and antioxidants in the body, which can cause tissue damage and is linked to chronic disease. And they had higher angiogenic capacity, which refers to the body’s ability to form new blood vessels.

All this suggests that being around trees is somehow linked to having a healthier heart, though these are just biomarkers, not rates of heart disease or major cardiac events. But while scientists have yet to prove directly that being around trees causes your heart to be healthier, it’s not the first study to suggest a link. In 2015, a study of American women found that rates of heart disease went up in certain areas after a beetle invasion killed off a significant number of trees. Other studies have suggested that being around trees can reduce stress, which in itself may affect your risk of heart disease. Luckily, whether it qualifies as heart medicine or not, spending more time hanging out under trees couldn’t hurt.

[h/t Cardiovascular Business]

Elephants Are Evolving Without Tusks Thanks to Poaching

iStock.com/LeighGregg
iStock.com/LeighGregg

Natural selection can take millions of years to shape a gene pool, but in parts of Africa, the extreme pressures of poaching may have changed elephants in just a few decades. As National Geographic reports, more tuskless elephants have emerged in regions where their ivory has made them a target.

Elephant poaching has long been in a problem Africa, but the crisis reached a fever pitch during Mozambique's 15-year civil war. Between 1977 and 1992, 90 percent of the elephants living in the country's Gorongosa National Park were slaughtered for ivory used to fund the conflict.

The diminished numbers aren't the only thing that looks different about Gorongosa's elephants today. Poachers often kill male elephants first because they have bigger tusks, and once they're eliminated, the hunters will go after females. Typically, about 2 to 4 percent of all female African elephants never develop tusks—but among female elephants that survived Mozambique's civil war, that number is 51 percent. The effects of poaching can also be observed in the next generation. Roughly 32 percent of female elephants born after 1992 are tuskless.

The trend can be seen in other parts of Africa where poaching has ravaged elephant populations. In Ruaha National Park in Tanzania, elephant behavior researcher Josephine Smit has observed that over one fifth of female elephants older than 5 years lack tusks. Tusklessness rates reach about 35 percent in females over 25.

The statistics are even harder to ignore in South Africa's Addo Elephant National Park, where tuskless animals made up 98 percent of all female elephants in the early 2000s. South Luangwa National Park in Zambia, Lupande Game Management Area in Zambia, and Queen Elizabeth National Park in Uganda each reported higher-than-average rates of tusklessness immediately following the ivory wars of the 1970s and '80s.

Though poaching is on the decline thanks to bans on the ivory trade and other conservation efforts in Africa, its impact can still be felt. In East Africa, the elephant population was nearly halved between 2008 and 2018. The establishment of wildlife preserves, DNA tracing, and GPS tracking are just a few of the ways conservationists are working to crack down on poachers and restore the species.

[h/t National Geographic]

This Map Shows All the Trees in New York City

Tim Wallace/Descartes Labs
Tim Wallace/Descartes Labs

Trees may not be the first thing that comes to mind when you picture big cities, but they're an essential part of many urban landscapes. By maintaining a healthy tree population, a city can clean the air, provide shade to buildings, and improve the quality of life of its residents.

To quantify the impact trees have, officials first need to keep track of how many grow within city limits—a task that's harder than it sounds. Even with thousands of volunteers working on the ground, tallying all the trees in a city like New York can take years, according to City Lab, and such surveys often don't account for the trees growing in parks or on private property. Using artificial intelligence, researchers at the geospatial analytics startup Descartes Labs have found a way to map all the trees in major cities without taking to the streets.

To make the New York tree map below, Descartes programmed a machine learning model to identify tree canopies from satellite images. This isn't as easy as pinpointing green spots: The program had to be taught to distinguish trees from other greenery, like grass and shrubs, using artificial intelligence. This sets it apart from other tools used to map vegetation like the Normalized Difference Vegetation Index (NDVI), which only accounts for light wavelengths, not height.

Map of New York City's Trees.
Tim Wallace/Descartes Labs

When applied to New York, the tree-mapping technology provides a different view of the city. Some of the most heavily trafficked areas, like downtown Brooklyn and Times Square, are blank spaces on the map. Not surprisingly, parks like Forest Park in Queens and Central Park in Manhattan have the densest concentrations of trees, but some affluent neighborhoods, like the West Village and the Upper East Side, also have plenty of greenery.

New York's vegetation may be impressive by some city's standard, but it's nothing compared to what it was 400 years ago. Here's what Manhattan looked like in 1609.

[h/t City Lab]

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