What will the slice of the tree tell?

Passing through the forest and noticing the old stump, the inquisitive person will certainly stop and pay attention to the mossy tree cut. What does he remember? What could I tell by finding a voice? Having wiped off the moss cover, it is easy to notice circles that are crossed out by cracks. The rings of the tree can tell a lot. About the youth of the plant, its life cycle, cold colds and hot, arid days. Before the eyes of knowledgeable people is revealed year after year, decade after decade. This science has arisen recently, it is called dendrochronology.

The concept of dendrochronology

The study of transverse sections is not difficult. The cut of the tree is examined under a microscope, each annual layer is measured in millimeters. According to the measurements, a special schedule is drawn up, it indicates the change in the thickness of the rings. The graph creeps up, if the thickness of the rings is wider (tree-friendly years), the graph decreases, when the years were arid, heavy. After analyzing the fresh cut of the tree, and plotting the graph, you can get a chronicle of his life, indicating the weather conditions during the life of this plant, that is, the last years of our time. Finding in the forest saw off an ancient tree, you need to do the same job and get a schedule. It can be used to judge the weather conditions of the period in which it grew. So year after year one can go deeper into history.

But not everything is so simple. In European forests, ancient trees do not survive for more than three hundred or four hundred years, except that the oak tree can sometimes reach the half-millennium. But to study the cut of a tree of hardwood is very difficult. Vague rings reveal secrets very reluctantly. In a more favorable position were scientists of America. There, some trees lived life for a whole millennium. These are some gymnosperms, yellow pine, Douglas fir. Even high-mountain pine trees were found, which lived for four and a half thousand years. During the excavations on the site of the home of the Indians , spits were found, on which it was possible to compile dendrochronological charts for a whole millennium.

Annual rings. Research in Russia

For years, scientists have studied only the wood of America. Europe turned out to be a white spot in this area. Only after the war in Russia did the scientists search for ancient spears. Northern regions were favorable for research. The soils here are well moistened, and the frozen soil perfectly preserved many tree trunks. A huge "harvest" of wood scientists gathered during excavations in ancient Novgorod. Here, several thousand different rocks were found, stratified one at a different depth. Layer after layer was opened by scientists archaeological material: church risers, log floors, log buildings of wells. Finds were found at an eight-meter depth. But how was it possible to relate the age of isolated finds? Sections of the tree trunk were prepared with more than three thousand copies. For each breed, it was necessary to build its dendrochronological scale.

Dendrochronologists have done a tremendous job. They were not just graphs. In order to establish a standard chart, it was necessary to study the entire history of the ancient city, the annals, to determine in which year a particular wooden structure was erected.

Aegean dendrochronological project

Work in the high-profile Aegean dendrochronological project has been going on for 35 years. Its goal is to create an absolute dendroshkal for the Middle East and Aegean regions inclusive from the trees of the first millennium BC, to modern artifacts. The work is carried out by scientists at Cornell University in the USA. Main results of the project:

• Absolute dendroscales of such breeds as oak, cedar, juniper, pine are executed. Their period is estimated to 750 g. BC.
• The construction of a floating Aegean dendroshkala is completed with an accuracy of 2657-649 BC (according to the juniper).
• Also, the cut of the tree over the juniper helped build a dendroshkala floating during the period 2030-980 BC. The results were published in 2005.
• Known problems on the "Roman gap" and the EVA problem were identified.

The achievements of American scientists are still considered controversial, since the probability of error in some cases is from 100 to 200 years.

Research in Finland

One of the most suitable places for research was northern Finland. In these places the climatic boundary line passes. Professor Jan Esper argues that the sunken trunks retain all the information for hundreds of years. So, a small cut on a tree, lying in a cold lake, will tell you a lot. In the north of Finland there are many such lakes that contain priceless information. Dendrochronologists say they will be able to uncover the secrets of the climate for two thousand years. The workers of the laboratory with the help of a special drill manually extracted samples of tree rings. Further they were examined under a microscope with the help of computer technology. The compiled dendrochronological charts helped to understand how the climate changed and even when volcanic eruptions occurred on the territory.

Climate change

According to the data received, scientists were able to establish that on the planet every millennium the average temperature dropped by 0.3 degrees. It continued until the beginning of the twentieth century - the Industrial World Revolution. The development of scientific and technological progress has led to a large increase in the amount of greenhouse gases on Earth. This period dendrochronology has not been studied in detail.

At the time of the Roman gladiators, the climate on the planet was much warmer. "Warm phase" can be called the Middle Ages. Then came the cold snap, which continued every year until 1900. On the contrary, our modern man is now worried about global warming. As you can see, even a small cut of the tree branch can tell a lot. Unfortunately, with the onset of the greenhouse effect, with the conditions in which the atmosphere and climate are polluted, in some way, from human activities, these dendrochronology data can only testify to temperature fluctuations.