Cell Structure Linked to Longevity of Slow-Growing Ponderosa Pines

An image of a pit membrane, the cellular structure linked to slow growth, drought resistance and longevity in ponderosa pines

A new study led by Beth Roskilly, a University of Montana (UM) alumna, and Dr. Anna Sala, Professor in the Division of Biological Sciences at UM and IoE affiliate, has linked cell structure to the longevity of slow-growing ponderosa pines. The study, published in the Proceedings of the National Academy of Sciences (PNAS), finds that "ponderosa longevity might hinge on the shape of microscopic valve-like structures between the cells that transport water through the tree." 

"Ponderosa pines, like people, cannot have it all,' said Roskilly, the paper's lead author. 'Drought resistance contributes to longevity but also to slow growth. In other words, there is a fundamental tradeoff based on xylem structure. Our study suggests that trees with fast growth become large quickly, which can be beneficial for young trees competing for resources, but they are more vulnerable to drought and can die at earlier ages. On the other hand, trees that grow slowly are more drought resistant, which enhances longevity." 

"Ancient trees are special for many reasons,' said Sala, [who is also] an adjunct professor in the W.A. Franke College of Forestry and Conservation. 'They are beautiful, they make the highest quality musical instruments, they help maintain diversity, and they store atmospheric carbon in wood for a long time. But the results of this research also suggest they are special because forest managers cannot make just any ponderosa pine tree live for centuries no matter how hard they try. For ponderosa pines to become centennials, their wood must possess this unique structure.”

The full article, "Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species," can be found online on the PNAS website.


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