Dinosaur forests mapped

Feb 28, 2012 By Adele Rackley
Dinosaur forests mapped
The new maps show that the Earth was covered by bizarre monkey-puzzle trees.

The first detailed maps of the Earth's forests at the time of the dinosaurs have been drawn up. The patterns of vegetation, together with information about the rate of tree growth, support the idea that the Earth was stifling hot 100 million years ago.

High temperatures and possibly more caused forests to extend much closer to the poles and grow almost twice as fast as they do today.

The findings have implications for understanding the long-term .

Scientists at Royal Holloway, University of London, plotted the maps after creating a database of more than two thousand fossilised sites from the , when were at their peak.

"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 it was mostly pines," said Emiliano Peralta-Medina, who led the study.

At that time the humid tropics extended over a wider area than now, and temperate climates – like the UK's – reached much closer to the poles, which had more tree cover than ice.

It seems though, that just before the dinosaurs went extinct the forests changed as angiosperms – flowering plants – made an appearance.

"Flowering trees similar to present-day magnolias took off, bringing color and scent to the world for the first time," says Peralta-Medina.

The angiosperms gradually took over habitats previously dominated by the conifers, until by the end of the Cretaceous they are the most common tree species.

As well as mapping the fossil forests, the team gathered measurements of tree rings – which indicate annual growth rate – from samples of fossil trees and from earlier studies.

They found that Cretaceous trees grew twice as fast as their modern counterparts, particularly nearer to the poles.

"Some 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," explains co-author Dr. Howard Falcon-Lang.

The reason for this baking hot climate seems to have been extremely high levels of in the atmosphere - at least 1000 parts per million (ppm) compared to 393 ppm today.

"If carbon dioxide concentrations continue to rise unabated, we will hit Cretaceous levels in less than 250 years," explains Falcon-Lang. "If that happens, we could see forests return to Antarctica."

"It's unlikely that dinosaurs will be making a comeback," he added.

The findings are published today in Geology.

Explore further: NASA's HS3 mission continues with flights over Hurricane Gonzalo

More information: Peralta-Medina, E, Falcon-Lang, HJ, 2012. Cretaceous forest composition and productivity inferred from a global fossil wood database. Geology 40(3) doi: 10.1130/G32733.1

Journal reference: Geology search and more info website

Provided by PlanetEarth Online search and more info website

4.6 /5 (5 votes)

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210
1 / 5 (1) Feb 28, 2012
A 1000 parts per million...! With the same land mass as today and slightly different placement of continents and ocean currents. Higher CO2 but far more trees (No people to cut them down at least). Trees producing Oxygen as fast as they could. Trees producing like this for millions of years. Shouldn't the oxygen content of earth's atmosphere have been a much higher percentage than now..? The fauna of that time would have needed or, have adapted to this possibility. Is there no proof of a higher oxygen content? And nitrogen; fixed for consumption by the massive microorganism population required to make the plant life sustainable. Plant life that was everywhere it is not today. Oceans too warm for life as we see it now because the warmer waters could not hold as much oxygen, unless, atmospheric pressure was greater than now, in which case, the oceans would even be heavily populated, which, again argues for a higher O2 content...what do you think?
word-
Lurker2358
5 / 5 (1) Feb 28, 2012
210:

Both the O2 and CO2 would have been much higher.

This can be confirmed forensically by examining the respiratory systems of insects, since many species of ancient insects were much larger.

It has been shown that giant insects would need a much higher concentration of Oxygen in order to breathe properly to get the energy they would need to fly.

There are dragon fly ancestors in the fossil record which are larger and more massive than most modern song birds, although the timing of that is supposedly some 2.5 to 5 times older than the range of most dinosaurs.

An increase in Oxygen content air pressure has been shown to produce gigantism or rapid growth in some fish species (experiment was done in a pressurized chamber vs room conditions, though I don't know what controls were in place for food consumption and other factors.)

Presumably, the extra oxygen is incorporated into oxidizing the metals in fossil soils, i.e. common rust, limestone, silica, corundum, other minerals.
barakn
5 / 5 (3) Feb 28, 2012
With the same land mass as today and slightly different placement of continents and ocean currents.
Ocean levels were much higher than today, leaving major portions of central North America, most of Europe, and the edges of Africa and South America inundated. Also the Atlantic Ocean was much smaller, making for a larger Pacific, and Australia was still joined to Antarctica.
Lurker2358
3.7 / 5 (3) Feb 28, 2012
Since world population is increasing at 14% and world per-capita living standards and energy consumption are probably increasing 5% per decade, this means total world energy consumption is increasing around 43% over the next 2 decades.

Since it's unlikely the developing nations, where the majority of this increase will be occurring, are going to have high amounts of alternatives, they are likely to get most of the energy from fossil fuels.

I figure by the time you back out the amount of CO2 human civilization makes, but is taken up by the environment to get the actual value we produce, and then multiply back by 1.43, then subtract the environment's uptake amount back from this, the slope of the Keeling Curve in 2032 will be somewhere between 3.78 and 4.6PPM per year, having averaged about 3.2 between now and then.

If it became linear at this point, then that's 68 years remaining before 2100. 68 * 4.6 = 312.8

20 * 3.2 = 64

395 64 313 = 772PPM CO2 @ 2100a.d.
Lurker2358
not rated yet Feb 28, 2012
the above figure does not count positive feedback from CO2 bombs or methane bombs in the Arctic, Antarctic, or elsewhere.

The carbon bombs in the Arctic and permafrost alone are supposed to be an additional 200 to 400PPM of CO2 and CO2 and methane equivalents.
Graeme
not rated yet Feb 28, 2012
What was the undergrowth like? Nowadays most undergrowth is angiosperms, but was it fern, moss and lichen back then?
Lurker2358
not rated yet Feb 28, 2012
What was the undergrowth like? Nowadays most undergrowth is angiosperms, but was it fern, moss and lichen back then?


http://en.wikiped...nopteris

Article suggests it may have been as large as a small tree.

Of course, we have hundreds of different types of plants and trees all living in the same region in the U.S., so it's not like we should take anything from just a few fossil samples as being representative of the whole.

We have I think 4 different species of oaks on this property alone. Then there's pine and sycamore, not to mention in the surrounding region, Gum, imported Tallow tree, Pecan, Walnut, pear trees and more. there's even wild fruit trees and vines: crab apple, and mayhaw, and black berries and more.

I don't even know which ones are native, lol.

anyway, point is life thrives in so many ways, so don't stereotype ancient life based on a few fossil samples.