Global team of scientists determine how much heat ‘fingerprint’, drought is too much for forests – Watts Up With That?
The authors conclude that limiting Earth’s warming will determine the viability of many of Earth’s forests.
UNIVERSITY OF FLORIDA
CREDIT: CSABA MÁTYÁS, PROFESSOR EMERITUS, UNIVERSITY OF SOPRON, HUNGARY
How too hot is too hot and how is too dry for forests on Earth? A new study from an international team of researchers has found the answer – by looking at trees that have been dead for decades.
Just published in the magazine Nature Communications, study that compiles the first global database of accurately georeferenced forest dying events, at 675 sites dating back to 1970. The study included all forested continents, following then compares that information with existing climate data to determine hot and arid climate conditions. causing these recorded episodes of tree death.
“In this study, we’re letting the forests of Earth talk to each other,” said William Hammond, a plant ecologist from the University of Florida who led the study. “We gathered data from previous studies that recorded where and when trees died, and then analyzed how the climate was during death events, compared with long-term conditions.”
After performing a climate analysis on the observed forest mortality data, Hammond noted, a pattern emerged.
“What we discovered is that on a global scale, there is a pattern of consistently drier and hotter temperatures – what we call a ‘hotter arid fingerprint’ – that can show us that how unusually hot or dry it must be for the forest to be in danger. Hammond, an assistant professor in the UF/IFAS department of agronomy.
According to him, the fingerprints show that the phenomena of forest mortality occur continuously when the hottest and driest months of the year are even warmer and drier.
“Our hotter drought fingerprint reveals that global forest mortality is associated with enhanced extreme climate events,” says Hammond. “Using climate model data, we estimate how often these previously lethal climate conditions will become even hotter, compared with pre-industrial climates – the frequency plus 2 degrees Celsius is 22% higher (plus 3.6 degrees Fahrenheit), to 140%. at plus 4 degrees C (plus 7.2 degrees F). ”
Those higher temperatures would double how often forests around the world see droughts that kill trees, he added.
“Plants do an extraordinary job of capturing and sequestering carbon,” says Hammond. “But the death of plants not only prevents them from performing this important role of carbon capture, but plants also begin to release carbon as they decompose.”
Hammond says that relying on trees and other plant species to capture and sequester carbon, as some proposed climate solutions have suggested, makes it important to understand what hot is ‘too hot’. ‘ and how dry is ‘too dry’. “Otherwise, death events, like those included in our database, could wipe out the planned carbon gain.”
One of the study’s co-authors, Cuauhtémoc Sáenz-Romero of the Universidad Michoacana de San Nicolás de Hidalgo in Mexico, provided an example of how recent climate patterns affect Mexican temperate forests.
“In recent years, the dry and warm season from March to May has been even drier than usual, but also warmer than ever,” he said. “This combination is putting a lot of stress on the trees ahead of the rainy season that runs from June to October. For example, in 2021, more than 8,000 mature trees were killed by bark beetles in the Monarch Butterfly Biosphere Reserve in Central Mexico. The impact of the Pacific La Niña current leads to drier, warmer conditions; a deadly combination that facilitates pest outbreaks. ”
Hammond has also developed an interactive application on ‘s website International Tree Mortality Network stores the database online and allows others to submit additional observations of forest mortality to the database.
EXPLAINER
‘Georeferenced’
Using maps or aerial images, scientists assign them real-world coordinates.
‘There is land’
Information confirmed or confirmed by direct observation and measurement. In the case of machine learning, it refers to checking the results for accuracy.
The organization, founded and coordinated by co-author Henrik Hartmann from the Max Planck Institute in Germany, among others, is a collaborative effort among scientists on every forested continent and aims to coordinate integrates international research efforts into forest dying events. Hammond is the network’s data manager.
“We hope that this paper will create a little urgency about the need to understand the role that warming plays in mortality in forests,” said Hammond. “In addition, we hope that our open access database will enable additional studies, including other climate traces from local to regional scales. The remote sensing and climate modeling communities currently need ground-based datasets to validate their predictions about important processes such as forest mortality. One of the factors that was really important to this study was to bring all this data together for the first time, so that we can pose a question like this at a planetary scale.”
The article, “Global Field Observations of Tree Death Shows Hotter Drought Traces for Earth’s Forests,” will be available at nature.com/articles/s41467-022-29289-2 . In addition to Hammond, Sáenz-Romero and Hartmann, it was co-authored by A. Park Williams, University of California, Los Angeles; John Abatzoglou, University of California, Merced; Henry D. Adams, Washington State University; Tamir Klein, Weizmann Institute of Science; Rosana López, Universidad Politécnica de Madrid, Spain; David D. Breshears, University of Arizona; and Craig D. Allen, University of New Mexico.
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‘s mission University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge related to agriculture, people and natural resources and to provide that knowledge to maintain and enhance the quality of human life. With more than a dozen research facilities, 67 county extension offices, and award-winning students and faculty at the UF College of Life and Agricultural Sciences, UF/IFAS delivers science-based solutions education for the agricultural and natural resource industries of the state as well as all Florida residents.
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JOURNEYS
Nature Communications
DOI
RESEARCH METHODS
Data analysis / statistics
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Global field observations of dead trees reveal a hint of a hotter drought for Earth’s forests
ARTICLE PUBLICATION DATE
April 5, 2022
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