Trees are broadly classified as deciduous (shed leaves seasonally) or evergreen (retain foliage year-round). They are also grouped as coniferous (cone-bearing, often needle-leaved) or broadleaf (typically with wider leaves). There are around 73,000 estimated tree species worldwide, with over 9,000 possibly undiscovered
Tree lifespans vary greatly, from around 30 years for some fast-growing species to over 5,000 years for the oldest known specimens like the Great Basin bristlecone pine. One bristlecone pine, Methuselah, is about 4,853 years old and was a sapling when Egyptian civilization began. Another in the same area is over 5,000 years old, and their exact locations are kept secret to protect them. A clonal colony of quaking aspen called Pando in Utah is estimated to weigh over 5,987,416 kilograms (6,600 tons) and is believed to be over 80,000 years old
Environmental Benefits:
- Air Quality: Filter pollutants; urban trees in the U.S. remove an estimated 711,000 metric tons of air pollution annually. Roadside trees can reduce nearby pollution by over 50%.
- Climate Change: Absorb CO2; a mature tree can absorb over 21 kilograms (48 pounds) annually. Forests in the U.S. offset about 16% of the country’s greenhouse gas emissions.
- Water Quality: Reduce stormwater runoff by 15-27% annually in urban areas. Forested watersheds provide drinking water to over 180 million Americans. Tree roots help filter pollutants from runoff.
- Cooling: Urban trees can lower temperatures by up to 9°C (16°F). Shaded surfaces can be 11 to 25°C (20-45°F) cooler.
Record-Breaking Trees:
- Tallest: Hyperion (coast redwood, California) at 116.07 meters (380.8 ft) . Its exact location is kept secret to protect it from damage.
- Widest Trunk: Árbol del Tule (Montezuma cypress, Mexico) with a diameter of 11.62 meters (38.1 ft). It’s about 1,400 years old, possibly over 2,000.
- Largest Volume: General Sherman (giant sequoia, California) with 1487 cubic meters (52,500 cu ft). Estimated mass (wet) in 1938 was about 1,910,000 kg (2,105 short tons).
- Widest Canopy: Thimmamma Marrimanu (banyan, India) covering 21,900 square meters (5.41 acres).
- Oldest: Methuselah (Great Basin bristlecone pine, California) at approximately 4,853 years old . Alerce Milenario (Patagonian cypress, Chile) potentially older at ~5484 years.