How trees produce food from sunlight and carbon dioxide
How trees defy the laws of physics
About the amazing structure of a tree’s trunk
Air pollution and trees. Combined, New York City’s five million trees yearly remove an estimated two thousand tons of air pollutants, in addition to more than forty thousand tons of carbon dioxide from the air. Over an entire year, trees remove about .05 percent of the city’s air pollutants. It follows that people in well-treed neighborhoods breath easier than those were trees are absent. The more trees in a city the better (Haskell, p. 203.)
Distribution of trees on our planet. Ninety percent of all tree species on earth live in tropical forests (Tudge, p. 27). The further you travel north or south from the tropics at the equator, the fewer the diversity of the species of trees you’ll find. The endless forests of Canada, for example, are dominated by only nine native species of trees including a few conifers and the quaking aspen. In the whole U.S., there are only about 620 native species of trees. India, which is much smaller than the U.S. has around 4,500 species of trees, and in one region of Peru where studies have been conducted within a 15 hectare area, 825 tree species have been identified. Tropical America (both North and South) have tens of thousands of species of trees (ibid., p. 279).
How many trees are there? No one knows how many tree species exist on planet earth (Tudge, p. 27). Scientists’ best estimates are that there are approximately 60,000 species of trees (not including thousands of hybrids) in the world of which 600 are conifers. The total Continue reading →