Posted on 28/02/2012
The new maps show the earth was covered by monkey-puzzle trees
The first realistic maps of the Earth's forests at the time of the dinosaurs have been drawn up by researchers at Royal Holloway, University of London and are published today (28 February) in the leading journal, Geology.
The maps provide the clearest picture yet of this bizarre "lost world" - and also show how the planet baked under a stifling hot climate.
To produce the maps, scientists studied a time called the Cretaceous Period - about 100 million years ago - when dinosaurs were at their peak. They created a database of every fossilised forest site ever discovered from this age - numbering several thousand - and plotted them on maps.
Mr Emiliano Peralta-Medina from the Department of Earth Sciences at Royal Holloway, who led the study, said: "Our research shows that weird monkey puzzle forests covered most of the planet, especially in the steamy tropics. At mid-latitudes, there were dry cypress woodlands, and near the North Pole, it was mostly pines."
He continued: "Just before the dinosaurs became extinct, all that changed. Flowering trees similar to magnolias took off, bringing colour and scent to the world for the first time."
In addition to mapping the fossil forests, the research team studied the width of the annual "tree rings" in the fossil trees - a measure of growth rate. They found that Cretaceous trees were growing twice as fast as their modern counterparts. This effect was greatest closest to the poles.
Co-author Dr Howard Falcon-Lang added: “Some of our fossil trees from Antarctica had rings more than two millimetres wide on average. Such a rate of growth is usually only seen in trees growing in temperate climates. It tells us that, during the age of the dinosaurs, polar-regions had a climate similar to Britain today.”
The reason for this baking hot climate seems to have been extremely high levels of carbon dioxide in the air - at least 1000 parts per million (ppm) compared to 393 ppm today.
Dr Falcon-Lang remarked: “If carbon dioxide concentrations continue to rise unabated, we will hit Cretaceous levels in less than 250 years. If that happens, we could see a return of forests to Antarctica. However, it's unlikely that dinosaurs will be making a comeback."