A weather-beaten pine clinging to a rocky slope in Italy is being called the oldest tree in Europe ever to be scientifically dated.
According to a new paper published in the journal Ecology, the species of Heldreich's pine, nicknamed "Italus" by researchers, is at least 1,230 years old. Even more surprising, despite lacking a substantial canopy, this particular pine appears to be thriving, with heavy ring growth added to its trunk over the last several decades.
"The increment observed in the last decades contradicts the reduced growth that typically occurs as cambial age increases," the researchers write, "especially considering the widespread growth decline and dieback that various Mediterranean ecosystems have recently experienced."
A team from the University of Tuscia discovered the ancient pine after an exhaustive four-year field survey within Italy's Pollino National Park, a sprawling mountainous area in the country's southern region that is rich with patches of old-growth forests. Its location on a steep rocky slope with exposed dolomitic bedrock likely not only protected it from past logging efforts, but also protected it from any wildfires that may have plagued the region over the centuries.
While the researchers knew simply from looks alone that they had found an ancient specimen, they ran into one big problem when it came time to accurately date it. The inside of the pine with the section containing the oldest rings had completely deteriorated.
"The inner part of the wood was like dust — we never saw anything like it," team member Alfredo Di Filippo from the University of Tuscia told NatGeo. "There were at least 20 centimeters of wood missing, which represents a lot of years."
To fill in the missing record, the team employed an innovative technique that focused on the tree's roots. Much like the trunk, roots include growth rings that can be used to determine age. Fortunately, owing to its location on a rocky slope, the roots of Italus were conveniently exposed for sampling. Using radiocarbon and tree ring dating, researchers were able to create a chronology that best reflected the tree's true age.
"Radiocarbon dating of root samples, enhanced by wiggle matching after producing a crossdated, floating root chronology, placed the oldest root sample within a timeframe that, in turn, allowed a root ring‐width series to be crossdated with a stem one," they write. "Once the floating root chronology was anchored to the crossdated stem chronology, the length of the root chronology pushed back the innermost ring dating of Italus by 166 yr, to 789 CE."
In an email to MNN, study lead Gianluca Piovesan said identifying and accurately dating old-growth trees like Italus is critical for understanding more about the biology and ecology of wild habitats, as well as highlighting the need to protect the natural sites hosting them.
The curious case of this particular specimen's renewed vigorous growth, the researchers write, also warrants a closer look.
"Further research should investigate the driving factors behind this resumed growth in such old trees, considering as possibilities higher air temperature under non‐limiting water stress, carbon dioxide fertilization, or trends in the deposition of air pollutants," they conclude.