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Professor Mat Disney and colleagues from NASA recently published aÌýstudy inÌýNature Scientific Reports, showing that some of the world's tallest trees, the coastal redwoods (Sequoia sempervirens)Ìýof northern California, are potentially much more massive than previously thought.

Mat and the team used terrestrial laser scanning (TLS) to measure the 3D size and shape of these trees across several sites. It is the first time redwoods have been measured in this way using TLS to estimate their volume and mass. This tells us how much carbon is stored in the trees over their lifetimes and in such old-growth forests more generally.

Coastal redwoods and their close relatives, the giant redwoods (Sequoiadendron giganteum), are some of the most massive living things on earth and can live for more than 2,000 years. The TLS measurements are able to capture the tree form in ways that have not been seen before,Ìýas shown in the image. Redwoods of a similar age can have very different shapes, reflecting their different life histories even within a single stand.

The largest tree measured by the team was theÌýColonel Armstrong, which is nearly 90m high, and over 3m in diameter at the base.ÌýThe threats such trees face were illustrated last summer when the Colonel Armstrong wasÌý. The measurements suggestÌýthat the ColonelÌýweighs around 110 tonnes, comparing very closely with the only other independent estimates by expert tree climbing teams using time-consuming manual measurements. Significantly, the figures were up to 30% higher than those based on commonly applied models using satellite estimates of forest carbon.ÌýIt thus suggests that these currently underestimate carbon in tall forests across wide areas.

Mat's work is showing how to improve satellite estimates and find new carbon along the way. It was funded in part by , through Mat’s colleague, of the University of Maryland, and the mission.

The results were featured in a number ofÌýnews outletsÌý¾±²Ô³¦±ô³Ü»å¾±²Ô²µÌýÌý(£). Mat also appeared in a feature,ÌýÌýon 29 November (about 19 minutes in),Ìýtalking about scanning trees, carbon and climate.

Perhaps most excitingly, they also appeared inÌý, created by artist and science communicator , as part of herÌý‘Plants Go Global’Ìýseries. This is an excellent and rather different way to communicate new plant science.