A new international study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. This number was formulated by collecting tree density information from more than 400,000 forest plots around the world. But the total number of trees has plummeted by roughly 46 percent since the start of human civilization. The results provide the most comprehensive assessment of tree populations ever produced and offer new insights into a class of organism that helps shape most terrestrial biomes.

Source: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14967.html ...

The magic number is 42 m/s (94 mph). Using mathematical data and physical experiments, scientists say they have found the law that governs the resistance of wooden beams under stress. According to the study (link), researchers hung weights from wooden rods and pieces of pencil lead to record the amount of force needed to snap the cylinder. As one might sense, they found that for a fixed length, increasing the diameter made the rods stronger: They could bend more before breaking. This would make tall skinny trees most vulnerable, but, as the team points out, trees don’t grow taller without getting disproportionately thicker as well. By incorporating established laws of tree allometry - which explain the relationship of tree size parameters ...

Chewing sticks are used by many people instead of toothbrushes. The neem tree grows in many Asian, African, and Middle Eastern countries. Indigenous people in these areas know that chewing neem twigs is good for their teeth. The epidermal tissues contain chemicals that kill bacteria and reduce inflammation. The study of how indigenous (native) plants are used by different cultures is known as ethnobotany.

Ever wondered why two of the world's most delicious fruits - the mango and the avocado - have such enormous seeds? Turns out they likely evolved to be swallowed whole by megafauna, like our modern-day rhinos and elephants, that once ruled the Earth, to be deposited far away from their host plant and wrapped in a fresh dollop of fertiliser. That's why these seeds are nicknamed 'ghosts of evolution'.

The coco-de-mer palm tree (Lodoicea maldivica) is endemic to the Seychelles. Its seeds are the largest and heaviest of any plant in the world, and have been highly prized over the centuries, which has almost driven the palm tree to extinction.

In 2005 Swedish millionaire Johan Eliasch purchased a 400,000-acre (1,600 km2) area of land in the heart of the Amazon rainforest from a logging company for the sole purpose of it’s preservation.

Johan Eliasch, born in Sweden, is the Chairman and CEO of Head N.V. the global sporting goods group, and is the former Special Representative of the Prime Minister of the United Kingdom.

In 2005, Johan Eliasch created the Rainforest Trust and purchased for preservation purposes a 400,000-acre (1,600 km2) rainforest area in the heart of the Amazon rainforest near the Madeira River. Johan Eliasch co-founded Cool Earth in 2006, a charity he co-chairs, which sponsors local NGO's to conserve endangered rainforest and has over 120,000 registered members. ...

The manchineel tree (Hippomane mancinella) has taken the title of world’s most dangerous tree. This evergreen grows up to 15 metres (49 ft) tall, and is native to tropical southern North America and northern South America. It has reddish-greyish bark, small greenish-yellow flowers, and shiny green leaves ranging in size from 5 to 10 cm (2–4 inches) long.

All parts of the tree contain strong toxins, some unidentified. The leaves and fruit of the tree superficially resemble an apple tree, however one bite of the tree’s fruit can cause abdominal pain, vomiting, bleeding, or death due to an acetylcholine inhibitor known as physostigmine found in the fruit. In addition, its milky white sap contains phorbol and other skin irritants, producing s ...

The Brazilian Jaboticaba tree well and truly takes advantage of all the surface area on its trunk by growing its sweet, grape-like fruits all over it. It's said to have evolved its trunk-fruit so animals could reach them and distribute the seeds.