Dendrology

We are talking about the terms “Dendron” and “Logos”, of Greek origin, meaning tree and study respectively. This term was created in 1668 by Ulisse Aldrovandi (Italian natualist founder of the Botanical Garden of Bologna) with the publication of Dendrology. As a tree grows, it generates new rings. These rings serve to identify years of growth, age, orientation, etc. Therefore, if we study tree rings well, we can know well what happened in the past.

Thanks to Dendrology, geological processes can be studied through tree rings. The geology of the terrain is changing over time caused by external geological agents. Water and wind, rain, etc. There are different geological agents that act to shape the landscape. Geological elements such as rocks and their formations change over time. Thanks to tree growth rings and studying them, it is possible to know what happened in the past. The study of geological processes through tree rings is a branch of Dendrology known as Dendrogeomorphology.

It is a very important source of data for territorial, urban, infrastructure or natural management studies. We must know that for all this type of human action it is necessary to know the terrain we are on and its evolution. That is, for developments in urban areas or infrastructures, it can be interesting to know the evolution of the place where it will be built. The same happens with the species of flora and fauna existing in this same place. The set of all studies necessary to be able to carry out the construction in accordance with the lawsuits is known as an environmental impact study. Dendrology has an important place in these environmental impact studies.

Dendrology applied to climate

We know that information about changes in the geology of the land is obtained not only from tree rings, but also from the climate. Although most of us know that by counting the rings of trees we can know their age, the truth is that this is not entirely correct. Each tree has a type of growth different from the rest and it depends on each species. Not all trees form the same rings and grow in the same way . For this reason, the formation of these rings can also provide us with information about the prevailing climate at the time the specific tree developed.

Dark rings form during the winter. It is a denser and more compact wood that helps the tree to defend itself against low temperatures. Plants must survive harsh environmental conditions in winter and summer. Usually these are two seasons of the year whose environmental conditions are more extreme and, therefore, need to create defense adaptation mechanisms.

One is a thicker wood that is reflected in the darker rings. In this way, lighter rings are generated in summer with less compact wood and darker rings with more compact wood. The transparent rings are wider, as the tree enjoys good temperatures and nutrients. In this way, it has a greater plant activity than it allows to extend the rings for a longer time.

On some occasions, we can find clear rings that are too narrow. This could be a sign of historic droughts. Without water, the tree cannot grow. In this way we see that the growth ring is quite narrow but still clear. Different types of information are not being disclosed. On the other hand, the fact that the ring is transparent does not reveal that there were continuous high temperatures. On the other hand, we are seeing that because it does not grow and is narrow compared to the other wide light rings, it indicates that the tree has not enjoyed the nutrients.

Normally, the presence of narrower or wider rings indicates the amount of nutrients available in the medium . If you have a tree with very wide dark rings, they reflect long, harsh winters. On the other hand, transparent rings are also analyzed for their width. In this way, we can know if the summers were more or less long and if they had high or low temperatures.

Climate change and tree rings

Climate change is not studied only by the increase in greenhouse gases and temperature changes at the global level. It can also be studied through bioindicators known as tree rings. Dendrology is responsible for studying fossil trees that also provide information about the climate of other times. In this field we know what is known as dendroclimatology.

We must bear in mind that the study of climate change is essential for the management of natural resources today and in the future. We cannot plan what our economic activities will be in the future based on the study of the present. It is necessary to know the different oscillations that the climate has had throughout the history of the planet. These fluctuations can be known very well thanks to Dendrology. Tree rings can reflect a great deal of information to us, not just about temperatures and tree growth, but also about the evolution of temperatures and environmental conditions.