SANTIAGO – Analyzing the link between climate change and the growing mortality of araucaria, a species of evergreen coniferous trees, has kept scientists busy for nearly a year in southern Chile.
Researchers have analyzed close to 50 types of fungus and bacteria obtained from the roots and branches of araucaria affected by tree blight in the Nahuelbuta Range, some 600 kilometers (373 miles) south of Santiago.
The research project, headed by the University of Concepcion and a private paper and cardboard manufacturing company (the Compañia Manufacturera de Papeles y Cartones, or CMPC), seeks to determine the origin of a blight that has killed both young and old araucaria trees.
One of the hypotheses that is being studied by the scientists is that “environmental stressors” could predispose the trees to fungus or bacteria that was previously harmless, but which has become lethal because of climate change.
In a 2,460-hectare (6,079-acre) conservation area in the Nahuelbuta Range, nearly 70 percent of araucaria trees have been affected by the blight in some degree.
“It is likely that these trees suffered some type of physiological stress, which allows any pathogenic attack to become much more severe,” Eugenio Sanfuentes, a researcher at the University of Concepcion, told EFE.
Scientists have focused on the discovery of phytophthora cinnamomic on some of the tree samples, which is a soil-borne water mold that has devastated forests in Australia, the United States and Southeast Asia.
It is possible that the mold “was spread through human activities,” such as the use of vehicles to cross the mountain range, Sanfuentes said.
According to Jean Pierre Lasserre, a technology and planning manager at the CMPC, although phytophthora cinnamomic could be dangerous for araucaria trees, analyses have still not managed to determine if the mold is the cause of the higher tree mortality.
Nevertheless, the experts working on the project agree that abiotic factors (not caused by living beings), such as low rainfall, the lack of snow and greater temperature variability, could make these coniferous trees vulnerable to phytophthora cinnamomic as well as other fungi and bacteria.
“The trees’ defense systems are changing and weakening. They are using up more energy to attempt to remain healthy, which is why they end up becoming weak and vulnerable,” Sanfuentes said.
According to Chile’s National Forest Corporation (Conaf), tree blight affects 93 percent of the 320,000 hectares (790,000 acres) of araucaria that exist in Chile, of which 1 percent has already perished.