Researchers extract wood samples in Iceland to study ocean currents

24. 7. 2019 -

Researchers from Mendel University in Brno are currently participating in a research project to help understand the ocean currents in the northern hemisphere. Dendrochronologists from the Faculty of Forestry and Wood Technology recently visited Iceland to extract samples from driftwood on the north-eastern coast. They will now identify the species of the individual samples, along with their age and the places they originated from.

Iceland is unique in that there are essentially no forests because all the trees were cut down during the Viking era. The locals use tree trunks washed up on the shore for carpentry and construction. As driftwood is legally state property, the farmers that own the land buy driftwood from the government for a fee.

Discovering the origin of Icelandic driftwood has been a long-term project of the Icelandic Forest Service, led by Ólafur Eggertsson, who have already mapped most of Iceland as well as the shores of Svalbard and Greenland. With the help of their Czech colleagues, they are now working on the last unexplored coast of north-eastern Iceland. "Our colleagues' research has already shown that the wood mostly drifts across the Arctic Ocean from Russia. In the current location, we focused on the tree trunks that had the highest number of tree rings, which were up to several hundred years old. Obtaining such samples gives us a better chance of dating the trees and determining their origin," says Michal Rybníček, one of the dendrochronologists from the MENDELU Faculty of Forestry and Wood Technology.

The researchers have brought over one hundred wood samples from Iceland to Brno where they will now measure the width of the tree rings and plot them on a graph to obtain the average values. They plan to travel to England at the end of the year to compare their results with the database maintained in Cambridge. As Rybníček explains, "They have chronologies, or tree-ring histories, from all over the northern hemisphere," adding that the Icelandic driftwood will presumably be shown to come from Siberia.

He thinks that the oldest trees might have been cut down in the 1960s and 1970s during an intensive logging period in the territory of present-day Russia when the felled trees were transported on rafts. "Some of the trees might have been cut down during this time, while others were naturally washed into the sea by erosion since they still have the roots attached. During the spring thaw, the levels of the rivers rise, the tree trunks are washed into the water and then freeze into ice floes. These floes are then carried out to sea, where the ice gradually melts and the trees are carried by the currents," explains dendrochronologist Tomáš Kolář. He adds that most of the trees are obviously conifers, such as pine, spruce or larch, which were in the water for two or three years before being washed up on the Icelandic coast.

"Some of the trees were lying on the beach for many years and their wood had paled into a lovely white colour, and these were interspersed with newer additions from the last year," says Kolář. According to the Brno researchers, the current research will improve our understanding of ocean currents in the northern hemisphere. "We still don't know much about these currents and one of the objectives of our colleagues in this project is to study whether and how the currents are changing," says Rybníček