Russian scientists find new way to track Siberian temperature history

MOSCOW, May 22. /TASS/. Russian scientists found that the reaction of trees in Siberian forests to ambient temperatures increase due to global warming may be tracked very accurately by analyzing the changing character of reflected blue light from annual rings of trees. This way, scientists may learn more about the history of temperature changes in the North's remote areas, press service of the Russian Science Foundation (RSF) said.

"This method has been developed actively only over the recent decade, but its accuracy and applicability to big areas and to different types of trees have not been sufficiently studied yet. Therefore, we've decided to test this approach in Siberian forests, where larch is one of the main species," the Russian Science Foundation's press service quoted Alberto Arsak, head of the Laboratory for Integrated Studies of Eurasian Forest Dynamics at the Siberian Federal University (Krasnoyarsk) as saying.

According to the scientist and his colleagues, the Russian Arctic and mountainous regions presently are facing the most rapid climate change, as temperatures in their territories are rising many times faster in global warming than in any other parts of the world. Such changes may have extremely negative impacts on plants, which encourages ecologists to study how rare and widespread tree species are reacting to temperature fluctuations.

Traditionally, scientists obtain such information by measuring density and width of tree rings, which reflect summer and average annual temperatures. Such measurements require using special equipment and are highly time-consuming, which limits the use of this method in monitoring conditions of forests. Russian scientists have suggested that similar information may be obtained in a simpler way by tracking changes in intensity blue light reflected from the growth rings.

To test this idea, the scientist and his colleagues collected wood samples from three main larch species growing in six different regions of Siberia - from the Urals to Yakutia. They measured the annual rings width and monitored their interactions with blue light. The biologists compared the measurements' results with temperature data in the studied Siberian regions from 1961 to 2020, and they found several interesting patterns.

For example, the researchers have found that the reflected blue light intensity varies greatly for the wood of all three types of larch, which forms in spring and autumn, and the severity of these differences strongly depends on how warm the summer was in the corresponding year. This approach makes it possible to track very accurately how average summer temperatures change in the area where larch trees grow, as well as to study the impact from the changing climate in Siberia and the Arctic on tree growth, the scientists concluded.