A Rare Breed Of Ancient Trees With Incredible Lifespans Help Keep Their Forests Alive
A forest’s venerable elders are hugely important to the diversity, fitness and survival of the forest as a whole, new research shows – and they bring with them resilience and experience in managing change, as well as ‘a life of ecological interactions preserved in their immediate environment..
Scientists used models extrapolated from several previous studies to assess how many trees typically exceed normal limits for tree old age and to analyze the kinds of effects these old trees had on the rest of the flora that surrounds them.
A very small number of trees – less than 1% of a population – reach ancient status, sometimes growing up to 10 or 20 times longer than the average for the forest as a whole, according to the study.
These incredible outliers of the tree world can reach such a great age among species that don’t have a defined lifespan like us. Year after year, thanks to their genes, they resist everything life throws at them, until the day their luck runs out.
Yet the longer these rare gems live, the more likely they are to pass on these golden genes to a new generation.
“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 life history ‘lottery winners’ that reach much older ages that link the environmental cycles that span centuries,” says botanist Chuck Cannon of Morton Arboretum in Illinois.
“In our models, these rare, ancient trees prove vital to a forest’s long-term adaptive capacity, greatly expanding the temporal span of overall population genetic diversity.”
In other words, these elders have seen it all – and this experience written into the genetics of the trees is something that rubs off on the rest of the forest and on the younger trees as new seeds are planted. In some cases, thousands of years of experience can be passed on.
However, trees that have stood the test of time are not only important because of their genetic and biological diversity. They also provide shelter for endangered species and absorb carbon better than younger trees, the researchers found.
These old, ancient trees are now under serious threat, not just from climate change, but from global deforestation, which means extraordinarily old trees are becoming less common, with tree mortality rates increasing across the world. types of forests.
“As the climate changes, it’s likely that tree mortality rates will increase and it will become increasingly difficult for old growth trees to emerge into forests,” Cannon says.
“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.”
Old trees, by their very nature, cannot be quickly replaced. The only way to ensure we still have them is to protect mature trees while they continue to grow – and that means limiting the effects of climate change and deforestation.
Researchers liken the destruction of ancient trees to the destruction of animal species, in that once they’re gone, they don’t come back. Even the trees that eventually grow that old won’t have the same evolutionary history written in them.
As humans, we have a long history of respect and even reverence for ancient trees – and the authors of this latest study say we need to bring some of that concern back to older members of forests, so to ensure their survival for the future.
“This study is a reminder of the urgent need for a global strategy to conserve biodiversity, not only by preserving intact forests, but in particular the small remnant of a few ancient trees that have survived in managed forest landscapes,” says ecologist Gianluca Piovesan from the University of Tuscia in Italy.
The research has been published in natural plants.