Posted on 09/02/2015 10:56:17 AM PDT by Red Badger
The global map of tree density at the square-kilometer pixel scale. Credit: Crowther, et al
A new Yale-led study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. But the total number of trees has plummeted by roughly 46 percent since the start of human civilization, the study estimates.
Using a combination of satellite imagery, forest inventories, and supercomputer technologies, the international team of researchers was able to map tree populations worldwide at the square-kilometer level.
Their results, published in the journal Nature, provide the most comprehensive assessment of tree populations ever produced and offer new insights into a class of organism that helps shape most terrestrial biomes.
The new insights can improve the modeling of many large-scale systems, from carbon cycling and climate change models to the distribution of animal and plant species, say the researchers.
"Trees are among the most prominent and critical organisms on Earth, yet we are only recently beginning to comprehend their global extent and distribution," said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies (F&ES) and lead author of the study.
"They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services," he added. "Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don't know where to begin. I don't know what I would have guessed, but I was certainly surprised to find that we were talking about trillions."
The study was inspired by a request by Plant for the Planet, a global youth initiative that leads the United Nations Environment Programme's "Billion Tree Campaign." Two years ago the group approached Crowther asking for baseline estimates of tree numbers at regional and global scales so they could better evaluate the contribution of their efforts and set targets for future tree-planting initiatives.
At the time, the only global estimate was just over 400 billion trees worldwide, or about 61 trees for every person on Earth. That prediction was generated using satellite imagery and estimates of forest area, but did not incorporate any information from the ground.
The new study used a combination of approaches to reveal that there are 3.04 trillion trees—roughly 422 trees per person.
Crowther and his colleagues collected tree density information from more than 400,000 forest plots around the world. This included information from several national forest inventories and peer-reviewed studies, each of which included tree counts that had been verified at the ground level. Using satellite imagery, they were then able to assess how the number of trees in each of those plots is related to local characteristics such as climate, topography, vegetation, soil condition, and human impacts.
"The diverse array of data available today allowed us to build predictive models to estimate the number of trees at each location around the globe," said Yale postdoctoral student Henry Glick, second author of the study.
The resulting map has the potential to inform scientists about the structure of forest ecosystems in different regions, and it can be used to improve predictions about carbon storage and biodiversity around the world.
"Most global environmental data is thematically coarse," said Matthew Hansen, a global forestry expert from the University of Maryland who was not involved in the study. "The study of Crowther et al. moves us towards a needed direct quantification of tree distributions, information ready to be used by a host of downstream science investigations."
The highest densities of trees were found in the boreal forests in the sub-arctic regions of Russia, Scandinavia, and North America. But the largest forest areas, by far, are in the tropics, which are home to about 43 percent of the world's trees. (Only 24 percent are in the dense boreal regions, while another 22 percent exist in temperate zones.)
The results illustrate how tree density changes within forest types. Researchers found that climate can help predict tree density in most biomes. In wetter areas, for instance, more trees are able to grow. However, the positive effects of moisture were reversed in some regions because humans typically prefer the moist, productive areas for agriculture.
In fact, human activity is the largest driver of tree numbers worldwide, said Crowther. While the negative impact of human activity on natural ecosystems is clearly visible in small areas, the study provides a new measure of the scale of anthropogenic effects, highlighting how historical land use decisions have shaped natural ecosystems on a global scale. In short, tree densities usually plummet as the human population increases. Deforestation, land-use change, and forest management are responsible for a gross loss of over 15 billion trees each year.
"We've nearly halved the number of trees on the planet, and we've seen the impacts on climate and human health as a result," Crowther said. "This study highlights how much more effort is needed if we are to restore healthy forests worldwide."
Researchers from 15 countries collaborated on the study.
More information: Nature, DOI: 10.1038/nature14967
Journal reference: Nature
OH, THE HUGE MANATEE!!!!!!!............
If it weren’t for hugging trees, they’d never have any love at all..............
7.5 % more trees pumping out that evil pollutant...
CO2...
Water vapor constitutes Earth's most significant greenhouse gas, accounting for about 95% of Earth's greenhouse effect (4). Interestingly, many 'facts and figures' regarding global warming completely ignore the powerful effects of water vapor in the greenhouse system, carelessly (perhaps, deliberately) overstating human impacts as much as 20-fold.
Water vapor is 99.999% of natural origin. Other atmospheric greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and miscellaneous other gases (CFC's, etc.), are also mostly of natural origin (except for the latter, which is mostly anthropogenic).
Human activities contribute slightly to greenhouse gas concentrations through farming, manufacturing, power generation, and transportation. However, these emissions are so dwarfed in comparison to emissions from natural sources we can do nothing about, that even the most costly efforts to limit human emissions would have a very small-- perhaps undetectable-- effect on global climate.
http://web.archive.org/web/20110308203927/http://www.geocraft.com/WVFossils/greenhouse_data.html
____________________________________________________________
So, greenhouse [effect] is all about carbon dioxide, right?
Wrong. The most important players on the greenhouse stage are water vapor and clouds [clouds of course aren't gas, but high level ones do act to trap heat from escaping, while low-lying cumulus clouds tend to reflect sunlight and thereby help cool the planet -etl]. Carbon dioxide has been increased to about 0.038% of the atmosphere (possibly from about 0.028% pre-Industrial Revolution) while water in its various forms ranges from 0% to 4% of the atmosphere and its properties vary by what form it is in and even at what altitude it is found in the atmosphere.
In simple terms the bulk of Earth's greenhouse effect is due to water vapor by virtue of its abundance. Water accounts for about 90% of the Earth's greenhouse effect -- perhaps 70% is due to water vapor and about 20% due to clouds (mostly water droplets), some estimates put water as high as 95% of Earth's total tropospheric greenhouse effect (e.g., Freidenreich and Ramaswamy, 'Solar Radiation Absorption by Carbon Dioxide, Overlap with Water, and a Parameterization for General Circulation Models,' Journal of Geophysical Research 98 (1993):7255-7264).
The remaining portion comes from carbon dioxide, nitrous oxide, methane, ozone and miscellaneous other 'minor greenhouse gases.' As an example of the relative importance of water it should be noted that changes in the relative humidity on the order of 1.3-4% are equivalent to the effect of doubling CO2.
http://web.archive.org/web/20100317023946/http://www.junkscience.com/Greenhouse
_________________________________________________________
Water Vapor Confirmed As Major Player In Climate Change
ScienceDaily (Nov. 18, 2008) — Water vapor is known to be Earth's most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change.
“A new Yale-led study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. “
Proving that Trees are remarkably sneaky and not to be trusted.
We can’t count existing trees but we can predict future climate numbers with total certainty!
“We can’t count existing trees but we can predict future climate numbers with total certainty!”
Well Trees are sneaky and they hide. Whereas we can see Polar Bears floating off to their deaths on melting ice floes, therefore proving Global Warming.
That was my first thought too. Some years ago I hiked 40 acres with a forester for 4 1/2 hours. My husband and I were trying to decide whether to buy out his brother’s half, or sell our 20 too. He showed us marketable trees, and “useless” trees, and how to estimate amount of usable areas within a marketable tree. I think he said they use waist height to determine diameter or circumference of a tree. There were many small trees with trunks 3 to 5 inches in diameter. He showed us how to select the best tree in a cluster, and then the 10 to 20 trees surrounding it that should be cut to allow the chosen one to grow into a good timber tree. If we had bought we would have wanted to sell some mature trees, and he gave us the name of a reputable guy who would remove trees carefully without clearcutting. Then we went to a lumber yard to find out what prices were being paid for various species of trees on this land. We ended up doing an IRS 1031 “Starker” exchange for 12 acres a lot closer to home.
So to answer the question, I am sure that each of the areas of state, national, etc. forest that were used in preparing these estimates had their own standards of what size tree counted as a tree, and without that information, it is hard to say what is meant by a tree, versus a sapling. Also, with aerial counting, there is no way to know what diameter of foliage was considered a tree. I strongly suspect that a forest of much taller trees produces more CO2 than does one composed of second growth saplings or small trees. As any farmer can tell you weeding allows much better production of the main crop. The other issue about mature forests or jungles like the Amazon is that there is often more diversity of plants and animals. One of the arguments on the Amazon is that they have a huge number of species many of which have not been identified. A number probably have medicinal properties which we may never learn about if the Amazon is largely destroyed.
The US forests were no doubt more dense and extensive than they are now before Europeans came. There are descriptions of extensive forests in the East with huge trees 6 and more feet in diameter, and relative clear forest floors. This would be one result of natural burning. The Shenandoah Valley was kept burnt off by the Indians and was used as a Buffalo common prairie where the various tribes suspended warfare for the hunt. Another Buffalo prairie was north of the Green River near Mammoth Cave. There were probably fewer trees, but much larger ones covering more total acres.
“Attenborough (Michael Palin): (slapping the side of a tree) Well here it is at last ... the goal of our quest After six months and three days we’ve caught up with the legendary walking tree of Dahomey, Quercus Nicholas Parsonus, resting here for a moment, on its long journey south. It’s almost incredible isn’t it, to think that this huge tree has walked over two thousand miles across this inhospitable terrain to stop here, maybe just to take in water before the two thousand miles on to Cape Town, where it lives.
It’s almost unimaginable, I find - the thought of this mighty tree strolling through Nigeria, perhaps swaggering a little as it crosses the border into Zaire, hopping through the tropical rain forests, trying to find a quiet grove where it could jump around on its own, sprinting up to Zambia for the afternoon, then nipping back ...
(a native whispers in his ear)
Oh, super! ...
Well, I’ve just been informed that this is not in fact the legendary walking tree of Dahomey, this is one of Africa’s many stationary trees, Arborus Barnbet Gaseoignus.
In fact we’ve just missed the walking tree... it left here at eight o’clock this morning... was heading off in that direction... so we’ll see if we can go and catch it up.”
More of what I’m sure is wasted tax money to produce a “study” that a simple walk, drive, plane flight, or satellite picture could show.
love it
“. There are descriptions of extensive forests in the East with huge trees 6 and more feet in diameter,”
Those large trees were American Chestnut trees and they were still very common as late as 1900, after which the chestnut blight eliminated virtually every one of them.
Beeches grow really large too. There is one in Dumbarton Oaks in DC. Also I saw them in a museum display of the American Indidans. Also elms and mighty oaks. Incidentally, if you Google it you can find places to buy resistant American Chestnut trees to restock our forest lands. I’m thinking of getting some.
do bonsai trees count
Forgot to mention there was also a very large old black walnut on the land where I spent my childhood living in an old Dutch colonial home. The oldest part was built in the late 1700s. I’m sure this tree was already mature then. It was at least 5 feet wide at waist height. I visited a few years ago and it and all the other smaller black walnuts on the property had been cut down and sold for timber. Grrrrrrrr!!!!!
“Incidentally, if you Google it you can find places to buy resistant American Chestnut trees to restock our forest lands. I’m thinking of getting some.”
I’d definitely do it if there are any, but from what I’ve read we haven’t got a blight resistant American Chestnut.
The loss of that species was a great tragedy. It was the most common tree in Eastern Hardwood forests until 1904 and many trees were 6 ft thick and nearly 100 feet high. It was fast growing, provided beautiful wood and was a major food source for all sorts of wildlife.
I suspect there was a link between the death of the American Chestnut and the extinction of the Passenger Pigeons that used to feed on them. Of course Passenger Pigeons may not have been such a wonderful thing- there were billions of them and their droppings were a major health hazard.
Usually 5 or 6. I didn't start counting until I was 6.................B^)
I have a Silver Maple and fruit trees, and a Laurel Oak that I planted as an acorn in Fall of 2008. It is now about 30 feet tall...................
You know what is going to happen eventually?
ALL trees will be RF ID’d with those tags they use in store to prevent theft. Then all they have to do is fly over the area and count the pings...................
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.