“Palm trees do not sequester carbon at the same rate as our native canopy trees and do not provide shade, cool streets and sidewalks to help counteract the urban heat island effect that canopy trees, ”said Penni Redford, of Resilience and Climate Change. Manager of West Palm Beach.
Scientists are working on solutions to safely capture and contain atmospheric carbon. One approach is called “land sequestration” – which basically involves planting trees. A tree absorbs carbon during photosynthesis and stores it for the life of the tree.
But Florida beloved palms are the least efficient at sequestering carbon. The average palm tree in South Florida only absorbs 5 pounds of CO2 per year.
Compared to other trees – oaks, mahogany, pines and cedars – which can sequester over 3,000 pounds of CO2 over their lifetime, it may be better to exclude palms in favor of more deciduous or coniferous trees. .
Kristine Crous, senior lecturer at Western Sydney University, explains that palm trees do not produce wood, so they are poorer at storing carbon.
Even if palm trees are not good at sequestering carbon, cutting them down is not the solution. Instead, programs in West Palm Beach and Miami Beach, Florida are taking the initiative to plant trees better able to handle changing weather conditions.
“The southern living oak, Quercus Virginiana – large canopy trees, can withstand occasional floods and hurricanes and is salt spray resistant, provides habitat for birds and a variety of mosses and bromeliads in southern Florida, ”Redford said.
Even without accounting for logging and deforestation, Mother Nature knocks down a lot of trees. As the Earth continues to heat rapidly, the loss of trees hurricanes and floods will become even more of a concern in the future.
However, in the case of palm trees, the best the solution may not be to simply replace them with more palm trees. Instead, they should be replaced with more efficient trees to alleviate the climate crisis.
But we can’t blame palm trees alone, as the type of tree is only one piece of the puzzle.
Crous told CNN that tree age matters too: Young trees absorb less carbon dioxide than older trees.
“Yes, tree species are important, some grow faster than others and therefore their response to high CO2 may also differ,” Crous said. “But it is important to distinguish the responses of younger trees versus older trees.”
Scientists set out to study whether you can really teach old trees new tricks to help them adapt to a changing climate.
Age is not just a number
Young trees and mature trees do not adapt to changes in the same way. So “just planting more trees” to fight climate change is not a universal cure.
Climate change strengthens hurricanes, brings down mature trees, and even entire forests, which are most needed to mitigate climate change.
“Planting trees is good, but valuing old-growth forests is just as important,” said Crous.
Research shows that mature oak trees can increase their rate of photosynthesis by up to a third in response to higher CO2 levels. In just the first three years of the 10-year project, 175-year-old oaks clearly responded to an increase in CO2 by increasing their rate of photosynthesis.
“We specifically aimed to quantify the photosynthetic response (carbon uptake) of these trees to future levels of atmospheric CO2,” said Anna Gardner.
This is great news from a carbon mitigation perspective. We still need to reduce human greenhouse gas emissions, but knowing that some tree species are able to adapt to increased levels of CO2 is encouraging.
“Planting trees will definitely help reduce CO2 levels,” Crous said. “But since trees take a long time to mature, this will be a delayed effect, and we really need to reduce emissions now by including other measures as well.”
The study looked at a variety of things from the age and type of the tree to the amount of sunlight available.
“Tree type is most definitely important in this regard. But more importantly, our climate models use data from seedlings and saplings to diagnose how old-growth forests will absorb future increases in CO2 from the air,” said David Ellsworth, tree teacher. Physiology at the University of Western Sydney.
This is why it is so important to save landscapes and forests with very dense older and mature trees.
“Our CO2 in the atmosphere and its impacts on the climate would be much worse if we did not have these old forests, and these old forests can adapt and increase the absorption of CO2 in the future,” said Ellsworth.
The study notes that the amount of forest carbon uptake in the future, and the subsequent carbon sequestration, “will be critical determinants of future atmospheric CO2 concentrations. Thus, quantifying the photosynthetic response under a High CO2, especially for mature trees, is essential for understanding forest carbon uptake under changing atmospheric composition. ”
Plant new trees in Florida
Trees alone will not solve the climate crisis, but they can help if we know how to use them correctly.
Redford says West Palm Beach gives 1,000 native trees a year to residents and businesses to plant.
“We have an active tree planting program,” says Redford of the program they use in West Palm Beach. The objective is to help Floridians not only to beautify their environment, but also to better prepare them for a future of global warming. To do this, Redford said, you have to be selective.
“We don’t use our canopy fund to plant palm trees,” Redford said.
“It may seem simple to select trees, but it takes thought and planning to get the right tree in the right place – one that can provide maximum benefits with minimum maintenance and does not contribute to other issues like fertilizer runoff and higher costs for water and maintenance, ”Redford said.
There is also a plan for when construction will result in tree removal. Redford said if a developer needs to remove trees and can’t replace them, he can contribute to a fund to have trees planted elsewhere.
“Of course we try to save the trees first or replant in that location,” Redford said. “But if that is not possible, we seek to plant trees where they are needed most.”
Planting trees to remove carbon dioxide from the atmosphere is a critical part of mitigating climate change, experts say. But it’s important to know which trees we are planting and to put more emphasis on saving the older trees we already have.