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Tanzania’s coastal forests (Swahili version)

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Forests. Street Trees. Tree Art. Tree Types. Tree Blindness. Ian Parsons spent twenty years working as a Ranger with the Forestry Commission, where he not only worked with birds of prey and dormice, but where he developed his passion for trees.

Tree Blindness

Now a freelance writer, Ian runs his own specialist bird tour company leading tours to Extremadura. For more details see Are you Tree-blind? That may seem like a silly question, but I think it is a condition that afflicts many conservationists and wildlife enthusiasts. Be thankful for trees. Some gifts are bright and beautiful.

Be thankful for trees

Some gifts are deep and lasting. We get both kinds from trees. Their beauty is obvious: The lacework of tree branches dusted with snow, the green shade they bring to summer streets and yards, the bright explosion of fall color, the grace they add to our landscape, the sense of continuity and richness they bring to our lives. Yet trees give us much more that is harder to see, says Jessica Turner-Skoff, whose role as treeologist at The Morton Arboretum is outreach about science and trees. Why Trees? Walking through the forest is my favorite activity in the world.

Why Trees?

It is where I feel truly myself. There is something about towering trees that calms me. The thought of why forests are even there often jumps to mind during my strolls. Plenty of plants seem to do just fine hanging out closer to the ground. Why have trees (and some forbs) taken to this vertical realm. In essence, forests are a prime example of an evolutionary arms race. Height also means better pollinator visibility and seed dispersal for many tree species.

There are many downsides to growing tall as well. 21 reasons why forests are important. Forests cover a third of all land on Earth, providing vital organic infrastructure for some of the planet's densest, most diverse collections of life.

21 reasons why forests are important

They support countless species as well as 1.6 billion human livelihoods, yet humans are also responsible for 32 million acres of deforestation every year. The United Nations declared March 21 the International Day of Forests in late 2012, part of a global effort to publicize both the value and plight of woodlands around the world. It was first celebrated March 21, 2013, nestling in between the U.N.'s International Day of Happiness on March 20 and World Water Day March 22. Trillions of trees. Three trillion: the latest estimate of the planet’s tree population, published in this issue of Nature (see page 201), exceeds the number of stars in the Milky Way.

Trillions of trees

At more than 7 times the previous estimate of 400 billion, the figure is impressive, but it should not necessarily be taken as good news. The forest-density study — which combined satellite imagery with data from tree counts on the ground that covered more than 4,000 square kilometres — also estimated that 15 billion trees are cut down each year. THREE TRILLION: Nature Graphics. Catalysing action for Indonesia's threatened trees. Indonesia is home to many remarkable trees.

Catalysing action for Indonesia's threatened trees

Towering dipterocarps reach heights of over 70m, mighty ironwoods produce one of the world’s hardest timbers and durians are notorious for producing a pungent fruit which you may love or hate depending on your taste. A dipterocarp tree. Credit: Arief Hamidi/FFI. How bears help trees climb mountains. Tree Flowers. Wood Handbook. 'Clocks' in tree-rings that could reset chronologies across the ancient world. Leonardo da Vinci's tree rule may be explained by wind. ( -- More than 500 years ago, Leonardo da Vinci observed a particular relationship between the size of a tree’s trunk and the size of its branches.

Leonardo da Vinci's tree rule may be explained by wind

Specifically, the combined cross-sectional areas of a tree’s daughter branches are equal to the cross-sectional area of the mother branch. However, da Vinci didn’t know why tree branching followed this rule, and few explanations have been proposed since then. But now in a new study, physicist Christophe Eloy from Aix-Marseille University in Aix-en-Provence, France, has shown that this tree structure may be optimal for enabling trees to resist wind-induced stresses. In his study, which is published in a recent issue of Physical Review Letters, Eloy explains that Leonardo’s rule is so natural to the eye that it is often used in computer-generated trees. Although researchers have previously proposed explanations for the rule based on hydraulics or structure, none of these explanations have been fully convincing.

How to make trees grow bigger and quicker. Scientists at The University of Manchester have discovered a way to make trees grow bigger and faster, which could increase supplies of renewable resources and help trees cope with the effects of climate change.

How to make trees grow bigger and quicker

In the study, published in Current Biology, the team successfully manipulated two genes in poplar trees in order to make them grow larger and more quickly than usual. Professor Simon Turner from the Faculty of Life Sciences led the research: "The rate at which trees grow is determined by the rate of cell division in the stem. We have identified two genes that are able to drive cell division in the stem and so override the normal growth pattern. The arboricultural explorer: Pakenham. Thomas Pakenham at the top of Mount Maenam, Sikkim, hunting rhododendrons, 2013.

The arboricultural explorer: Pakenham

11 of Britain's most legendary trees. Trees have had a tough time during the last 100 years.

11 of Britain's most legendary trees

Only by nurturing the seed of enthusiasm year after year will we be able to cultivate a lasting environmental legacy in our parks, streets, woods and green spaces First came Dutch elm disease in the 1920s, a fungal pathogen that killed tens of millions of elm trees in Britain, spread by beetles it continues to be a serious threat. Fast forward to today and another fungus is on the verge of causing mass destruction among another of our tree species. This time the tree under threat is ash and the pathogen is ash dieback. “Ash dieback has shown us what can happen to one species and will change our landscape just as much as Dutch elm disease did,” says Pauline Buchanan Black, director general of The Tree Council.

It has the potential to cause significant damage to the population and may now already be too late to prevent. The Great Old Ones: In Celebration of Our Tree Elders. Photograph from the 1917 "The National Parks Portfolio" (via Internet Archive Book Images) Trees are fascinating — if left undisturbed by humans and our axes, they can grow to incredible sizes, and live for thousands of years. Around the world, there are trees that have been growing for a much longer period of time than famed arbors like Methuselah or General Sherman. Some of these beautiful ancients may not look like much — some appear to be mere saplings, compared to the gigantic redwoods. Pando aspen grove at Fishlake National Forest (photograph by J Zapell/Wikimedia) "Probably” the tallest tree in the Tropics.

Trees, regardless of size, all break at the same wind speed. When a cyclone named Klaus tore across southwestern France in January 2009, it highlighted a strange phenomenon: Trees, regardless of their diameter, height, or elastic properties, don’t tend to break until wind speeds reach about 42 m/s (94 mph). This seemingly odd convergence has actually been observed by several historical scientists, including Galileo and Leonardo da Vinci, both of whom suggested that a mathematical law could explain the resistance of wooden beams under stress. Now, using data from a new experiment, scientists say they have found that law. In a study published this week in Physical Review E, scientists hung weights from wooden rods and pieces of pencil lead to record the amount of force needed to snap the cylinder. As one might intuit, they found that for a fixed length, increasing the diameter made the rods stronger: They could bend more before breaking.

Crown Shyness - Trees can shy away too! Crown shyness is a phenomenon observed in some tree species, in which the crowns of fully stocked trees do not touch each other, forming a canopy with channel-like gaps. Why? Well, scientists are not certain what causes these remarkable patterns. SJU Campus Tree Inventory.