The number of dying trees in the tropical rain forests of northern Australia each year has doubled since the 1980’s, and researchers say that this is probably the cause of climate change. tropical forests north of Queensland 49 years ago.Leading author David Bauman, a botanist at the University of Oxford, UK, states: “Trees are living organisms that are so durable that they need to be able to detect changes in rare forms such as tree death. Sites were first tested every 2 years, and then every 3-4 years, he explains, and the analysis focused on 81 key types.
Bauman and his team recorded that 2,305 of these trees had died since 1971. But they point out that, since the mid-1980s, the risk of tree deaths has increased from an average of 1% per year to 2% per year.Bauman claims that trees help to reduce global warming by absorbing carbon dioxide, thus increasing the number of tree deaths reduces forest resilience. “Tropical forests are crucial to climate change, but they are also at high risk,” he explains.
Climate change
The study found that the increase in mortality occurred simultaneously with the long-term tendency to increase the decrease in atmospheric pressure, which is the difference between the amount of vapor that can hold the atmosphere and the amount of water in it. holds for a while. When the number is high, water trees lose their leaves. “If the need for leaf-level respiration can be compared to the absorption of water from the good roots, it can lead to the leaves withering, all the branches dying and, if the stress persists, the tree dies,” Bauman said.
The researchers looked at other weather-related styles – including rising temperatures and measuring drought pressure in the soil – but found that the dry climate had a much stronger effect. “What we are showing is that this increase [at the risk of tree death] is also closely followed by an increase in atmospheric pressure, or drying force, which is a result of global warming due to climate change,” explains Bauman.
Of the 81 tree species in the study group, 70% showed an increased risk of death during the study period, including Moreton Bay chestnut (Castanospermumaustrale), white aspen (Medicosmafareana) and satin sycamore (Ceratopetalumsuccirubrum).The authors also noted the difference in mortality from the same tree species in each episode, depending on how high the atmospheric vapor deficiency in each building is.
“This is a set of information on which trees have been carefully monitored since the early 1970s, and this is the highest level of analysis,” says Belinda Medlyn, an ecosystem scientist at the University of Western Sydney, Australia.But he says more research is needed to determine whether the lack of vapor pressure is a major factor in climate change in increasing tree mortality.
Source Journal Reference:Bianca Nogrady, Trees are dying much faster in northern Australia — climate change is probably to blame, nature News (2022), doi: https://doi.org/10.1038/d41586-022-01358-y
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