Considering that two-thirds of the Earth's terrestrial plant and animal species call forests their home, that millions of people rely on healthy forests to survive and that forests are a critical source of carbon storage, it is hard to overestimate the importance of trees to the overall health of the planet.
Looking to the future, trees are going to be even more crucial as the human population approaches 8.3 billion by 2030. Most of these people will be in cities -- places where trees are not normally the focus of attention. And this could be a problem -- not to mention the ongoing deforestation of the world's forests to supply mankind with food and products.
Currently, the world is undergoing what the United Nations Population Fund (UNFPA) calls "the largest wave of urban growth in history." The agency notes that in 2008, for the first time in history, more than half of the world's population is living in towns and cities. This number will reach almost 5 billion by the year 2030, with the greatest concentration of urban growth in Africa and Asia.
During a November 20 CNN segment about urbanization and health, Gupta noted that the near-constant sensory stimulation that bombards most urban dwellers can cause spikes in cortisol, also known as the "stress hormone."
As a result, it can be difficult for the brain to hold things in memory. High concentrations of cortisol can "reduce your self-control, dull your thinking...it may even speed up cognitive decline, just from living in a city," says Gupta. "Think of it as your brain more rapidly aging." And there you have it: Living in cities is hazardous to your health. In a word: unnatural.
In this sense, "natural" means green. Gupta noted that "recent studies have shown just glimpses of green areas will make huge differences to your overall cognitive function. It makes you less distracted, less stressed and more relaxed." So the key is to "find green spaces in your city and make sure to use them as much as possible." Urban dwellers, it seems, can help keep their brain function healthy just by looking at a tree .
But in the future, how many trees will there be to look at? "Eight thousand years ago, large tracts of ancient forest covered almost half the Earth's land area," according to Greenpeace. "Today, only one-fifth of the original forests remain...The rest have been destroyed, degraded or fragmented by relentless human activity." Indeed, forests have been in steady decline for a long time. Even the collapse of the ancient native American Anasazi tribe was due in part to deforestation.
And while the rate of global deforestation has been showing signs of decreasing, the 2010 United Nations report Global Forest Resources Assessment asserts that it is "still alarmingly high."
Last year's United Nations report State of the World's Forests notes the "potential negative impacts on forest resources could include reduced investment in sustainable forest management and a rise in illegal logging...Land dependence, which had been easing, could increase, raising the risk of agricultural expansion into forests, deforestation and reversal of previous forest gains."
In the Book of Genesis, the Tree of Life in the Garden of Eden bears a fruit that gives everlasting life. After eating from the Tree of Knowledge of Good and Evil, Adam and Eve were banished from Eden to prevent them from eating from this immortalizing tree.
On Judgment Day, according to the Book of Enoch, God will give fruit from the Tree of Life to all those whose names are in the Book of Life. But God might be handing out hamburgers instead, because by that time the Tree of Life may have been cut down to make room for cattle farming.