Cut the trunk of a tree transversely and you will see that it has annular drawings. One for each year of tree life. Therefore, the number of rings provides information about the age of the tree. And not only that, the large rings indicate that it was a prosperous year from the point of view of tree growth, while the narrow rings indicated that it was a scarce year. In short, the trunk also reports on the evolution of time.
However, in the trees of the tropics there is no such information. Few trees have visible rings on the trunk. Therefore, the age of the tree - and the meteorological evolution - must be read in a different way in these trunks, for example by analyzing radioisotopes. However, they are slow and costly methods, and scientists have tried to develop other methods.
In the United States, several researchers at Princeton University have achieved it. According to his study, some tropical trees do not lack rings. They have rings but are invisible, and are even made visible by X-rays due to the calcium in them.
When you see the calcium of the trunks with X-rays you can quickly see the information of the trunk, the age of the tree and the evolution of time. Radioisotopes allow for a four-month work in a single afternoon using X-rays.