The firefighters watched as flames engulfed the tree. Nicknamed the SenatorIt grew in Seminole County Park in Florida., the bald cypressA type of tree that flourishes in wet areas such as swamps and usually grows to around 100 feet. was over 3,500 years old. It had grown to 165 feet. For generations, families had come to try to join hands around its 12-foot wide trunk. But the forest fire had put an end to it.

Such huge, ancient trees are vital to the planet: 1% of the largest trees hold 50% of the carbon stored in forests. A single sequoiaA Californian tree which can grow to around 250 feet. can neutralise the carbon footprint created by one person in their entire life.

Climate change has done damage to these giants. "Every major forest type, from Arizona and Algeria to Alberta and Argentina, wet and dry, is dying in ways that are historically unusual, from heat and drought," says Craig D Allen, a professor of ecology at New Mexico University. "Extreme events kill trees, and the worse periods are getting worse."

"Megadroughts", as Allen calls them, are particularly harmful. Large trees need more water and energy. Because droughts are becoming more frequent, trees have less time to recover. There is also an increased risk of fires.

Insects are another threat. Swathes of forest in the Rocky MountainsThe biggest mountain range in North America, running for 3,000 miles from Canada to New Mexico. have been lost to mountain-pine beetles. In the past, the beetles were killed off by very cold winters.

The figures are alarming. In the course of a year, 80% of British ColumbiaA province on the west coast of Canada. More than half of it is covered by forests.'s mature lodge-pole pines died. A few years ago, 129 million trees died in California.

It was to counter such destruction that a father and son from Michigan set out to clone the largest trees of each giant species in the US listed in the National Register of Big TreesThe size of each is calculated by adding the height to the circumference and a quarter of the width of the leaf canopy at the top..

The cuttings they collected were sent to a nursery so new trees could be grown. The aim was to establish descendants of 800 trees, all between 2,000 and 5,000 years old.

Some of the new trees have been planted in the same forests as the originals, others at new sites such as the PresidioA former military base. in San Francisco and the Eden Project in Cornwall. Part of the plan is to increase genetic diversity in places which have never had ancient trees.

Some experts have reservations. They argue that protecting whole areas of forest would be a better use of resources, and that to ensure biodiversity, samples should be taken from at least 50 trees of each species.

But David Milarch believes every single specimen has a contribution to make.

Yes: Ancient trees can take in up to 12 times as much carbon as younger ones, and contribute enormously to biodiversity. We must do all we can to preserve them. Every country should have an archive.  

No: Focusing on individual trees is a red herring when you are dealing with a problem as massive as deforestation. Ancient trees planted now will not necessarily flourish in modern conditions.   

Or... There are better ways of preserving ancient trees, such as providing them with irrigation and clearing the forest around them so that they have less competition and are at less risk from fire.