Trees are among natures most remarkable achievements, growing from a seed you can hold in your hand into a green giant several stories high. They are rugged survivors. They can live in baking hot deserts or icy arctic regions, competing with other plants for water and nutrients, while fending off cold, heat, drought, flood, poisons, parasites and predators. Trees can live for hundreds and even thousands of years, and teem with hundreds of different species of animal. At the same time, they provide us with fuel, food and shelter ?and even the oxygen that we breathe. A world without trees would be a barren, dry and polluted wasteland.