You may have heard that it is possible to determine the age of a tree from its trunk. This really is possible! Just watch your growth rings.
Growth rings are circles observed in the secondary xylem of the trunk of some plants, especially those in temperate climates.
The rings are formed thanks to an alteration in the activity of the vascular cambium. The vascular cambium is the lateral meristem responsible for giving rise to the secondary xylem. The vascular cambium, being a lateral meristem, is related to the growth in diameter of the plant. In temperate climate regions, where it is possible to observe well-defined seasons, the gearbox works in spring and summer.
Each growth ring is formed by spring wood and summer wood. Spring wood, formed in spring, is lighter and has thinner-walled cells. Summer wood, on the other hand, formed during the summer, is darker and has thicker-walled cells. In autumn and winter, the exchange remains at rest.
Assuming that wood is formed only in spring and summer, in temperate regions, it is possible to determine how old a tree is by counting these rings.
It is noteworthy that in regions where plants are subject to great environmental variations, it can form false growth rings and therefore, in these environments, the rings may not reflect the actual age of a plant. The thickness of the rings can be affected by environmental factors, being very common, in periods with a lot of rain, to present greater thickness.
In tropical and subtropical regions, the exchange operates throughout the year and, therefore, there is no visible ring formation.
by Vanessa do Santos
Graduated in Biology
Source: Brazil School - https://brasilescola.uol.com.br/biologia/aneis-crescimento.htm
