Bristlecone pine trees, the Earth’s oldest trees, can live beyond 5,000 years, while limber pine trees can live not more than 2,000 years.
The growth behavior of these two ancient Great Basin species in response to climate change was studied by researchers from the University of California, Davis. The team found out that for the past 50 years, the sub-alpine tree line has been constantly moving up the slope in the Great Basin, and more importantly, bristlecone pine tree could possibly face local extinction.
Tree lines are the elevated areas of a habitat where trees can thrive. Beyond these areas, no trees can withstand the environment to proliferate.
It was stated in the study that tree lines are expected to move up in response to climate change because these areas are controlled by growing season temperature. It was also observed that the limber pine trees are moving up faster than the bristlecone and seem to dominate the tree line, making it difficult for the latter to move up. With this establishment advantage of limber pine on the new habitat, the bristlecone might be excluded and possibly get locally extinct.
“We are seeing very little regeneration anywhere in bristlecone ranges except in the tree line and, there, limber pine is taking all the good spots. It’s jarring because limber pine is a species you normally see further downslope, not at the tree line.
So it’s very odd to see it charging upslope and not see bristlecone charging upslope ahead of limber pine, or at least with it,” said Brian Smithers, co-author and Ph.D. candidate in UC Davis’ Department of Plant Sciences. He further warned, “The things we’re doing today have legacy effects for thousands of years in the Great Basin. When those trees do start to die, they won’t likely be replaced because it’s just too hot and dry.”