A New Way to Reconstruct Ancient Climates Using Tree Anatomy
A recent study has uncovered a fascinating discovery – a simple blue stain could potentially unlock the memories of trees, revealing insights into past climates. By utilizing a combination of biological stains such as safranin and astra blue, researchers have found a way to identify changes in tree growth patterns that are indicative of cold summers and volcanic winters.
This innovative approach involves staining wood samples to detect the presence of lignin, a key compound that strengthens plant walls. When trees experience colder conditions that hinder proper growth, the production of lignin can be affected. The resulting blue rings in the stained wood serve as reliable indicators of climate history, allowing scientists to look back centuries and unravel variations in growing conditions.
The research team conducted their study in the Mount Iškoras region of northern Norway, collecting samples from Scots pine trees and common juniper shrubs near the northern treeline. By applying safranin and astra blue dyes to the samples, they were able to highlight cell walls lacking sufficient lignin, resulting in distinct blue rings that signify cold growing conditions.
Lead researcher Agata Buchwal, a dendroecologist from Adam Mickiewicz University in Poland, explains, “Blue rings look like unfinished growth rings and are associated with cold conditions during the growing season. We observed more blue rings in trees than in shrubs, indicating that shrubs are more adapted to cooling events and can be found further north.”
The study revealed that pine trees exhibited a higher sensitivity to cold temperatures compared to juniper shrubs, making them more reliable climate indicators. Significant drops in lignin production in certain years, such as 1902 and 1877, were linked to cold summers and potential volcanic eruptions during those periods.
While the findings shed light on past climate variations, the researchers acknowledge the need for further investigation to confirm the relationship between blue rings and cooling events. The data gathered from this study underscores the potential of multi-colored rings as evidence of shifts in growing periods, seasonal temperatures, and global climatic events.
Buchwal hopes that this research will inspire other scientific groups to explore the phenomenon of blue rings in trees and shrubs, paving the way for a network dedicated to reconstructing cooling events at the northern treeline over long timescales. The study has been published in Frontiers in Plant Science.
