The whiteness of the birch trunk has long delighted writers and poets, amazed ordinary people and aroused the interest of scientists. There are legends about the white bark of this tree, its properties are of interest to biologists and doctors.
The legend of the white color of birch bark
There is a Jewish legend that explains the origin of the white birch trunk.
Long ago, a birch tree grew in Job's garden. Job was not only a rich man, but also very honest. He lived in full accord with the laws of the Jewish faith. God was very proud of him. But one day the devil said to God: “It is not difficult to be rich and at the same time a good and honest person. After all, Job has everything he wants. Only in poverty does a person really show his good qualities. And God allowed the devil to test Job. Then Job became poor and sick. The disease disfigured him. For a long time Job was poor, ugly, lonely and sick. But he still remained an honest and good person.
Finally, the day came when God told Job that he had suffered enough, and man was once again allowed to lead a rich and happy life. Job was so overjoyed at this news that he ran to his wife to tell the good news. When he ran into the house, she was just going out onto the porch, carrying a pot of boiling milk in her hands. The couple collided with each other, the pan flew out of the woman's hands, and milk was poured over a birch tree in the yard. Since then, the birch has always had a white trunk. Because of the boiling milk, the birch bark began to peel off.
The scientific explanation for the whiteness of a birch trunk
Betulin is a substance that is contained in birch bark and stains it white. It was discovered in 1788 by the Russian-German scientist Johann Tobias Lovitz. The name of the substance comes from the Latin name for the wood species - Betula.
Betulin crystals are found in the cells of the outer layer of birch bark. Their structure resembles that of snow crystals. Due to this structure, the birch trunk appears white.
As you know, white reflects sunlight. Along with sunlight, trees are also affected by the heat of the daylight. When a tree trunk is dark, it absorbs heat at the same time as light.
White-trunk birch is a tree from northern latitudes that is exposed to cold during the winter. In such climates, heating the trunk in winter is harmful to the tree. If on a sunny day the bark heats up during the day and then cools down strongly at night, there will be a sharp temperature drop in the cambium, the tissue inside the trunk, which will weaken the work of reproductive cells between the wood and the bark.
The consequences of such temperature fluctuations for the tree are disastrous: sunburn, frostbite, loss of the ability to carry sap, and even complete death. By reflecting sunlight, the birch trunk does not heat up enough to harm the tree.
Thus, the white color of the trunk arose as a result of the adaptation of birch to cold climates.
