F:or for the first time scientists have provided clear evidence that the life span of tropical trees falls below the critical temperature threshold.
Results published in the journal PNAS: (Scientific Bulletin of the National Academy of Sciences) show that the life cycle of trees in the tropics decreases at temperatures above 25 ° C.
As temperatures rise rapidly in most tropics, tree mortality is likely to accelerate in much of the tropics, including the forests of the Amazon, the Pantanal, and the Atlantic Ocean;
Although tropical rainforests make up only 7% of the total land, they are home to about 50% of all animal, plant and plant species, and about 50% of the Earth’s forest carbon reserves. Thus, small changes in tropical forest activity can significantly alter atmospheric CO levels.2: – the most powerful anthropogenic greenhouse gas.
The new study is co-authored by Manuel Glor, a professor at the Leeds School of Geography, and Dr. Roel Briene, a professor.
Professor Gloron said: “Many areas in the tropics are heating up particularly rapidly, with significant areas becoming warmer on average by about 25 ° C.
“Our findings, which are the first to show that there is a temperature threshold, suggest that the longevity of trees in these areas is likely to be negative.”
Dr. Bryan added: “This shows that tropical forests may be more vulnerable to increased heat than previously thought,” he said. As a result of global warming, we are expecting a reduction in the life span of trees in the tropics.
“These results are a warning sign that, along with deforestation, global warming is putting additional strain on the Earth’s tropical forests.”
The research team, led by Dr. ul Uliano Lococelli of the Institute of Biological Sciences at the University of Sao Paulo in Brazil, spent four years studying data from more than 100,000 tree rings worldwide, belonging to 400 different tree species from 3,000 locations around the world.
Dr. Lococelli said: “In the tropics, trees grow on average twice as fast as in the cooler regions of the world. But they also have a shorter average lifespan of 186 years, compared to 322-year-old trees in other climates. Our analysis suggests that life expectancy in the retrograde zone is likely to decrease further.
“If tropical trees die sooner, it will affect how much carbon these forests can have, raising concerns about the future potential of forests to compensate for CO.”2: emissions from fossil fuel combustion. “It could also cause biodiversity changes or a reduction in the number of planetary species.”
Soil temperature rise
Currently, the average temperature in tropical rainforests ranges between 21 ° C և 30 ° C. According to the latest forecasts, the ground temperature will continue to rise, reaching an average of 2.5 ° C above the pre-industrial level over the next 10-20 years. The study shows that the effect of temperature on tree longevity will be exacerbated by dry conditions.
Climate change will also affect tropical forests outside of South America, such as the Congo Forest in West Africa, the world’s second largest tropical forest after the Amazon.
Dr. Lococelli added: “Although the tropical forests of the Amazon are close to this temperature, the temperature in Congo is lower. But with this great rise in temperature, we can begin to see signs of an increase in tree mortality. From this point of view, the scenario is rather gloomy. “
Professor Marcos Bakeridge, director of the Institute of Biological Sciences at the University of Sուլo Paulo and co-author of the study, added: “Future temperatures will be maintained in the near future, even if we take drastic measures to reduce emissions.
“Thus, it is inevitable that the critical threshold of tree longevity in the tropics will be exceeded more and more, so it will be possible to protect tropical forests and prevent greenhouse gas emissions.”
Reference. “Global analysis of tree trunks reveals rapid decline in tropical tree longevity with temperature” Uliano Maselli Lococelli, Roel JW Brienen, Melina de Souza Leite, Manuel Gloor, Stefan Krottenthaler, Alexandre A. de Oliveira, Jonathan Barichivcc, Dieter Anini Jochen Schöngart և Marcos Buckeridge, December 14, 2020 Scientific Bulletin of the National Academy of Sciences,
DOI: 10.1073 / pnas.2003873117:
Authors of the report: ul Uliano Lococelli, University of Sանo Paulo, Institute of Botany, S Պo Paulo; Roel Brienen, University of Leeds; Melina de Souza Leite, University of Sao Paulo; Manuel Glor, University of Leeds; Stefan Krotentaler, University of Pasau; Alexandre de Oliveira, University of Sao Paulo; Jon Onatan Barichevich, University of Pasau; Dieter Anhoff, University of Passau; Gregorio Cessantini, University of S Պo Paulo; Jochen Shongart, National Research Institute of the Amazon; Marcos Bakeridge, University of Sao Paulo.
Data from the World Meteorological Organization (WMO) show that from 2016 to 2020, the average global temperature is one of the hottest compared to any other period.
It is currently estimated to be 0.24 ° C warmer than the 2011-2015 world average. Data: NASA The National Oceanic and Atmospheric Administration (NOAA) designated 2016-2019 as the և first-second warmers of all time, respectively.
The research team estimated growth figures for more than 100,000 trees worldwide. Each of these rings, located on the trunks, represents one year of plant life, allowing you to estimate the age of the trees և growth rate (rate). The researchers also analyzed how climate affects the life cycle of trees.