Читать книгу Collins Complete Guide to British Trees: A Photographic Guide to every common species - Paul Sterry - Страница 11

When the tree begins to grow vigorously in the spring it forms large conductive cells that allow sap to flow freely through the trunk. As the season advances, cells produced by the cambium layer become smaller, with thicker walls for support, so they give a more dense appearance. In winter, cell production slows down and then ceases for a while; come the spring, however, there is a sudden burst of cell production and large cells are produced once more. The new growth of large cells immediately next to the thinner layer of dense cells gives the appearance of a ring. By examining a cut stump it is possible to count the rings and therefore discover the age of the tree, and also to find out which were the best growing seasons (see pp.).