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Reefer Madness

Marijuana has not been de facto legalized, and the war on drugs is not just about cocaine and heroin. In fact, today, when we don’t have enough jail cells for murderers, rapists, and other violent criminals, there may be more people in federal and state prisons for marijuana offenses than at any other time in U.S. history

Eric Schlosser on the U.S. war on marijuana in the August 1994 issue of The Atlantic. His cover story eventually became Reefer Madness: Sex, Drugs, and Cheap Labor in the American Black Market.

Read more at The Atlantic


And so my dream of seeing a redwood as tall as the Burj Khalifa comes to a disappointing end. Still, the science behind the limitation is a pleasantly interesting consolation prize. —MN


Why trees can’t grow taller than 100 metres

TYPICALLY, the taller the tree, the smaller its leaves. The mathematical explanation for this phenomenon, it turns out, also sets a limit on how tall trees can grow.

Kaare Jensen of Harvard University and Maciej Zwieniecki of the University of California, Davis, compared 1925 tree species, with leaves ranging from a few millimetres to over 1 metre long, and found that leaf size varied most in relatively short trees.

Jensen thinks the explanation lies in the plant’s circulatory system. Sugars produced in leaves diffuse through a network of tube-shaped cells called the phloem. Sugars accelerate as they move, so the bigger the leaves the faster they reach the rest of the plant. But the phloem in stems, branches and the trunk acts as a bottleneck. There comes a point when it becomes a waste of energy for leaves to grow any bigger. Tall trees hit this limit when their leaves are still small, because sugars have to move through so much trunk to get to the roots, creating a bigger bottleneck.

Jensen’s equations describing the relationship show that as trees get taller, unusually large or small leaves both cease to be viable (Physical Review Letters, The range of leaf sizes narrows and at around 100 m tall, the upper limit matches the lower limit. Above that, it seems, trees can’t build a viable leaf. Which could explain why California’s tallest redwoods max out at 115.6 m.

Source: New Scientist.
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Wood Gives Life to Deep Sea

So the floor of the deep ocean isn’t the best place to find forests of woody conifers. That’s de rigueur for most folks. Still, the remains of trees have a major say in the bustling lives of the strange creatures that do call the abyss home. That’s the word from the scientists of Germany’s Max Planck Institute for Marine Microbiology, where a study in leaving logs on the barren sea floor is drumming up surprising results.

Far from the submerged desert that many believe it to be, the deep ocean offers a menagerie of oddball worms, crustaceans, fish and microorganisms—just as soon as  the proper oasis pops up to provide nutrients. Geothermal vents are the most well-known example of undersea oases; sunken whale corpses, slightly lesser-known.

Now, enter the humble log.

Just as a tree is home to birds, insects, and fungus on land, the wood provides the perfect support for all manner of marine life. Despite having placed logs on the floor of the eastern Mediterranean, one of the most food-deprived areas known, the scientists found that “a variety of organisms managed to localize, settle, grow and reproduce” on their forestal deployments. The team even discovered some new species in the course of their efforts.

While fascinating on its own, especially in light of the driftwood creature communities washing ashore after Japan’s 2011 earthquake, the study may provide insight into the evolution and distribution of deep sea species otherwise deprived of regular sustenance. Click through for more. —MN


From Winners of the National Geographic Photo Contest 2012, one of 14 photos. Grand-Prize Winner: The Explosion! The subject’s name is Busaba, a well cared for Indochinese Tigress whose home is at Khao Kheow Open Zoo, Thailand. I had taken many portraits of Busaba previously and it was becoming more and more difficult to come up with an image that appeared any different to the others. Which is why I took to observing her more carefully during my visits in the hope of capturing something of a behavioral shot. The opportunity finally presented itself while watching Busaba enjoying her private pool then shaking herself dry. In all humility I have to say that Mother Nature smiled favorably on me that day! (© Ashley Vincent/National Geographic Photo Contest)

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