Rapidly growing trees die young and pose a risk of releasing carbon dioxide, which challenges forest forecasts of a “sinking” of planetary warming emissions, scientists said Tuesday.
The wood cover absorbs a significant portion of the carbon dioxide emitted by burning fossil fuels and plays an important role in predictions for its ability to reduce CO2 levels.
Current climate models expect forests to continue to act as carbon sinks this century, assuming higher temperatures and concentrations of CO2 will stimulate tree growth, thus helping them absorb more carbon as they mature faster.
But the study was led by the University of Leeds in the UK and published in the journal Nature Communications, They warned that this rapid growth is also linked to young dying trees – indicating an increase in the share of forests as carbon storage becomes “short-lived”.
When researchers examined more than 200,000 wood-ring logs from wood species around the world, they found that trade-offs between growth and longevity occurred in almost everything, including tropical trees.
Steve Volker, associate professor at New York State College of Environmental Sciences and Forestry, said in a report that the community has benefited from the ability of forests to soak up forests in recent decades.
But these CO2 rise rates are “likely to decrease as slow-growing and continuous trees are replaced by fast-growing but vulnerable trees”, He added.
“Our findings suggest that, like the story of the tortoise and the hare, they have vulnerable traits within fast-growing trees, while slow-growing trees have properties that allow them to survive.” he said.
The researchers said the findings show that trees’ chances of dying increase dramatically when they reach their maximum potential.
But fast-growing trees invest less in protection against diseases or pest attacks, or are more susceptible to drought, they said.
The average surface temperature of the Earth is one degree Celsius higher than pre-industrial levels, which is enough to increase the intensity of droughts, heat waves and super storms, causing more destruction by rising oceans.
Sink or through?
According to David Lee, Professor of Atmospheric Sciences at the Metropolitan University of Manchester in the United Kingdom, the Earth’s climate models are currently predicting that forest carbon emissions will continue or increase.
“This study shows the opposite, which compromises the increased CO2 forest as a carbon sink,” he said.
It refers to the notion that “fossil fuel-based emissions can be ‘compensated’ (or avoided by deforestation) by planting trees that do not really support scientific research.”
But Keith Kirby, a forest ecologist at Oxford University, said forests do not need to change their carbon role.
“We cannot believe in increased growth per unit area to maintain and improve forest carbon sink capacity, but this can be offset by deforestation and expansion of deforestation, which can be done in a sustainable way,” he said.
Global forests – especially tropicals – soak up 25 to 30 percent of humanity’s CO2, which warms the planet.
Last year, the football pitch of the primary, old growth trees was destroyed every six seconds, totaling about 38,000 square kilometers (14,500 square miles). Global forest monitoring.
© Agencies France-Press