The planet’s forests depend on a small group of ancient trees to survive and withstand environmental change and other perils, new research has found.
However, these long-lived trees can only reproduce in virgin forests and are currently threatened by climate change and deforestation.
Once you cut down old and ancient trees, we forever lose the genetic and physiological heritage they contain, as well as the unique habitat for nature conservation.
Scientists from the University of Barcelona, University Tuscia in Italy and Arboretum Morton in the United States have used a mathematical probability model to estimate the number of trees that exceed the average age of other trees in a forest.
They also analyzed data from previous studies to understand how these ancient trees affect the rest of the flora in the ecosystem.
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In their studyPosted in natural plantsthe researchers noted that old trees make up less than one percent of a forest’s tree population and can be 10 or even 20 times the age of other trees in the forest.
Despite their rarity, however, forest veterans are essential to maintaining the health and biodiversity of forest ecosystems.
It is likely that trees that achieve exceptional longevity pass on their genetic resilience to nearby new generations of trees, enabling them to cope with their changing environment and continue their continuity.
“We looked at the demographic patterns that emerge from old-growth forests over thousands of years, and a very small proportion of trees emerge as a life cycle ‘lottery winners who reach much higher ages that connect environmental cycles that span centuries,” said Chuck Cannon, director of the Tree Science Center at Morton Arboretum and one of the study’s authors.
“In our models, these rare and ancient trees prove vital to a forest’s long-term adaptive capacity, greatly expanding the temporal span of overall population genetic diversity,” he added.
The scientists added that the advantageous characteristics of century-old and millennial trees are not limited to preventing the wear and tear of aging. They also outperform typical mature trees in absorbing carbon dioxide and provide a unique habitat for endangered species.
The researchers also said that ancient trees do not follow a natural life cycle similar to other plant species or even humans; instead, their existence is mostly due to random events such as disease or fire.
“Mature, well-established trees are not programmed to age to a particular size or age,” they wrote. “[They] die from severe damage from external biotic and abiotic factors, such as pests and diseases, fires, winds and ice storms, or long-lasting adverse environmental conditions.
However, the existence of ancient trees is threatened by climate change and deforestation, and no physical mechanism exists to replace the loss of their parental presence in the forest.
“As the climate changes, tree mortality rates are likely to increase and it will become increasingly difficult for old growth trees to emerge into forests,” Cannon said. “Once you cut down old and ancient trees, we forever lose the genetic and physiological heritage they contain, as well as the unique habitat for nature conservation.
The researchers finally noted that, while forest restoration is an essential tool for preserving ecosystems, it is also crucial to protect forest elders and preserve the evolutionary history embedded in them.
“Ancient trees are known to be unique centers of biodiversity that provide key or unique ecosystem functions unmatched by managed forests,” they said.
“The loss of these trees is tantamount to species extinction, in that an irreplaceable genetic resource is being lost,” the researchers concluded. “For all these reasons, ancient forests with their unique stock of ancient trees are becoming increasingly important to protect.