Climbing the world's tallest trees
Giant sequoias can live for thousands of years and, as a result, achieve astonishing heights. They have the capacity to put on an incredible amount of wood, up to a cubic metre of wood a year, and can grow incredibly fast. Trees are in constant competition to grow taller in an attempt to reach the light - light drives photosynthesis and so is vital to plants’ success. With the help of expert climbers, Iain climbed to the very top of a 85-metre-tall, 1500-year-old Giant sequoia in California.