Among other things, Leonardo studied the structure of trees, established the rules of branched history (the science of determining the age of annual rings), and even hypothesized that their diversity depends on the weather.
Another important study was his rule on tree branches, which researchers have long cited. Da Vinci He wrote that the thickness of the tree branches, when adding any height, is equal to the thickness of the trunk. Biologists confirmed this observation (which, by the way, has long impressed mathematicians), and calculations showed that a constant cross-sectional area helps trees withstand the pressure of wind, ice and snow. But not for all trees!
Now Russian scientists – led by Sergei Grigoriev of the Saint Petersburg Institute of Atomic Physics – have found a new branching rule that works with all deciduous trees, which is science news.
The older Leonardo rule focused mainly on the thickness of the branches (that the thickness of the branch equals the combined thickness of the branches growing outside of it) and did not take the length into account. In contrast, the new rule uses the surface as a guide to examine branch width and length and predicts that long branches will be thinner than short branches.
According to the researchers, the relationship between the surface of the branches and the structure of the tree shows that the outer living layers control the structure of the tree. It’s like a football It will be a 2D object, and only two dimensions – the width of each branch and the distance between the branches – will determine the structure of any tree.
The new rule is a step forward, says Catherine McCullough, a botanist at the University of Wisconsin-Madison, but she has also expressed skepticism because
In most trees, the live part extends much deeper than the thin surface layer, and this is actually species dependent and dependent on age: an ancient giant oak can contain one centimeter of live wood.
But there may be species of tropical trees that have very deep succulents (the living part of the tree’s body that runs parallel to the annual ring that transfers moisture from the roots to the foliage) and most of their cross-section is a living tree.
To test their judgment, Grigoriev took pictures of trees of different species and analyzed the branches to make sure the real patterns matched expectations. The images allow direct measurement, but without touch, which is important when examining an organism.
Although the team has not yet studied evergreens, the rule has been validated for all the deciduous trees examined.
Their method was applied to maple, linden, birch, chestnut, oak and apple. They showed the same general structure.
Although manual measurement of branches can confirm the rule, it requires climbing into trees and checking all branches – a risky practice for both trees (injury) and scientists (trapped).
(Cover Image: Smith Collection/Gado/Getty Images)
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