This was announced by the federal forests on Thursday. The tree comes from the underwater forest, known since the 1970s, with around 100 standing tree trunks with heights of one to around 15 meters. The project aims to illuminate the genesis of the lake and gain insights into climate development and microplastic pollution.
Four rescue attempts necessary
It took several weeks to salvage the fir tree, which was around 18 meters deep and weighed six tons. Project manager Erwin Heine explained that the fire brigade needed four attempts to recover the ancient tree. With lifting balloons, rope rescue and cable crane, he was finally brought to the shore about 100 meters away.
Another 100 or so tree trunks are still in the lake – wood samples were taken from these using diving robots, divers and an underwater saw, which showed that the trees were of the same age. With the salvage of the silver fir, one wanted to find out why the trees are under water and not lying on the ground over time, Heine justified the complex action. The root body of the fir showed that it was weighed down by soil and stone deposits, causing the trees to stand in water. It is still unclear how they got into the lake.
Died 859 AD
The age of the recovered fir could be determined by a combination of examining the growth rings (dendrochronology) and the C14 method, which uses radioactive decay and the known half-life of the carbon isotope: “The tree has 247 growth rings and died in 859 AD “, it said in the broadcast. The tree began to grow around 600 AD – i.e. in the early Middle Ages.
According to Heine, there must have been a major natural event in the 9th century, such as a rock fall or an earthquake, which could explain why the trees are standing in the lake and why they all died at the same time. Trees in the nearby Attersee and Gosausee were examined as early as the 1990s and it was found there that trees died off in the 9th century. Now they want to find out whether there is a connection, says the project manager. More detailed analyzes are still pending.
Research project of the Boku
Based on an idea by the renowned US oceanographer Walter Munk, who came from Austria and died in 2019, and supported by the Walter Munk Foundation for the Oceans, Lake Altaussee has been researched since 2019 together with the University of Natural Resources and Life Sciences Vienna and the Austrian Federal Forests. For example, a multi-beam echo sounder was used to create a 3D model of the lake basin that shows sediment formations, larger stones, cracks and the like in the lake. The microplastic content in the lake is currently being investigated as part of the project. However, the first results do not indicate any particular deviations in the body of water, according to Heine.
You can find out more about the project in the video:
.responsive-container { position: relative; padding bottom: 53.25%; height: 0; overflow: hidden; } .responsive-container, .responsive-container iframe { max-width: 1920px; max-height: 1080px; } .responsive-container iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; borders:0; }
Source: Nachrichten
