This finding contradicts the usual assumption that tree growth eventually declines as trees get older and bigger. — Nate Stephenson, forest ecologist with the USGS Western Ecological Research Center

Plant a sapling, watch it grow, then watch a young tree grow, then look at an old tree.

Common sense tells us that the young tree is growing faster, taking up far more carbon, than an old tree. Recent research has proven common sense, and much of what has been written on trees, to be wrong.

The older trees get, the more growth, the more carbon they sequestrate.

An international team of researchers compiled growth measurements of 673,046 trees belonging to 403 tree species from tropical, subtropical and temperate regions across six continents, calculating the mass growth rates for each species and then analysing for trends across the 403 species. The results showed that for most tree species, mass growth rate increases continuously with tree size — in some cases, large trees appear to be adding the carbon mass equivalent of an entire smaller tree each year.

Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree.

What the study emphasises, is the importance of old trees. Cut down ancient woodlands, old growth forests, and we are destroying old trees.

Research in 2012 showed that big trees may comprise less than 2% of the trees in any forest but they can contain 25% of the total biomass and are vital for the health of whole forests because they seed large areas.

That an old tree has survived so long, often measured in centuries, not years, shows it is better adapted to climatic changes, otherwise it would not have survived so long.

Old trees, support other species.

If we allow grazing, we stop these old trees from re-seeding.

Remnants of the Old Caledonian Forest are starting to spread into areas fenced off to keep out grazing animals.

It only serves to highlight the crass stupidity of Environment Secretary Owen Paterson, who wants to relax the protection afforded to Ancient Woodlands, woodlands that date from 1600, the remnants of the post-Glacial forest.

The recent floods, have highlighted the need to retain water uphill, to slow the flow rate, to re-afforest, rewild.