The first living organisms appeared on our planet about 3.8 billion years ago and even then, some of them, although still very small and primitive, were already using sunlight to produce energy by the process of photosynthesis, of which the by-product, oxygen, slowly and slightly began to enrich the Earth’s atmosphere. A fundamental breakthrough in this aspect occurred after tiny, on-land, low plants, as a result of competition for light, about 380 million years ago, began to form large and even majestic trees, and later large, Carboniferous forests. Since then, there has been a significant increase in oxygen and decrease in carbon dioxide absorbed by plants, followed by the development of numerous groups of organisms, especially animals, including mammals. Trees have achieved many evolutionary successes, such as a record height of up to about 130 m, the incredible mechanical strength of their stems, or trunks, their longevity of up to more than 5,000 years, and an extraordinarily extended structure of branches and leafage of fundamental importance for the life of many animals, fungi and plants and for the proper circulation of carbon in nature, the compounds of which strongly influence the climate of the globe. They have taken over most of the terrestrial areas and there are about 80,000 species.