Trees

The World Resources Institute reports that 45 million acres of trees were lost in 2014 (an area twice the size of Portugal). But, also, a forest survey published in Nature finds there are about 3 trillion trees on Earth (far more than previously estimated). However, that's a 46 percent decrease since humans started cutting them down.

Update (December 22):  A study published in Nature Climate Change projects that unchecked warming could wipe out evergreen trees in southwestern U.S. by the end of this century.

Update (February 8, 2016):  A study published in Landscape Ecology warns that development projects are shifting forests to a more fragmented condition.

Between 2000 and 2012, the world lost more forest area than it gained, according to U.S. Forest Service researchers and partners who estimated a global net loss of 1.71 million square kilometers of forest -- an area about two and a half times the size of Texas. Furthermore, when researchers analyzed patterns of remaining forest, they found a global loss of interior forest -- core areas that, when intact, maintain critical habitat and ecological functions.

Update (February 17, 2016):  Bruce Melton writes about beetles, dying forests, and abrupt climate change.

Update (April 8, 2017):  Botanic Gardens Conservation International has created a database of over 60,000 species of trees. At least 15 percent of the species are considered at risk for extinction.

Update (May 29, 2017):  Tree plantations alone could not remove enough carbon dioxide from the atmosphere to limit warming to 2 degrees Celsius.

Update (January 14, 2018):  Daniel Meek discusses an infographic about deforestation.

To understand the ecological importance of trees to our planet, Alton Greenhouses, a greenhouse manufacturer based in the United Kingdom, analyzed various scientific studies and comments from environmentalists to imagine a world without trees. The results are alarming. In addition to flash floods and food shortages, humanity would also have to deal with widespread animal extinctions, accelerating climate change and the loss of materials.

Update (June 19, 2018):  John Vidal discusses how older, larger trees are most vulnerable to climate change.