How tall trees feed themselves

A faculty member at the University of Minnesota Duluth’s Biology Department has conducted research on tall trees that has been published in Nature Plants and will be highlighted in the journal Nature. Assistant Professor Jessica Savage has been teaching at UMD for about a year and is the lead author of a paper detailing the process tall trees use to transport sugar or feed themselves.

The article, “Maintenance of Carbohydrate Transport in Tall Trees,” was published today on An online subscription is required to fully nerd out and read the work, but a 277-word abstract is available for free.

Savage and a group of colleagues studied the anatomy of tall trees and saw dramatic changes as the trees grew taller. The new research demonstrated that as trees grow in height the phloem at the base of the trunk doesn’t just expand in length, it changes throughout and grows wider at the base.

“This is significant because it changes how we think about growth in trees and the factors that contribute to tree height. And this new knowledge could be applied to other areas of research including crop production,” Savage said in a news release. “It’s amazing that plants are able to transport sugar so efficiently even when they are tall.”

The research was conducted by first gathering samples of ten different tree types including Red Oak, Trembling Aspen, American Basswood and Sugar Maple. Savage and fellow researchers used a wood chisel to chip out a small piece of the trunks. The wood was then preserved, stained and sectioned into thin samples to be studied, measured and photographed under microscopes. They took measurements of a tree’s canopy by erecting a microscope and work station on scaffolding. The scientists also measured the pressure inside the cells of the leaves with a special technique developed by Dr. Jan Knoblauch, one of the co-authors.

Trees are able to transport sugars or carbohydrates passively. They don’t require a pump or boost of energy to move things from one place to another. Savage said that learning more about how this is possible could have major implications and she’s eager to continue her research.

It was a team effort for more than four years to gather the data, analyze results and publish this work. Savage collaborated with three other faculty: Dr. Michele Holbrook at Harvard University, Dr. Knoblauch at Washington State University and Dr. Kaare Jensen at Denmark Institute of Technology, and a large group of students that are included as co-authors.

Savage is now working on a larger study with more than 40 tree species at different stages of development to see if the results of this study apply universally. At UMD, she has also started a new line of research that takes advantage of cold winters.

“I want to learn more about the seasonal changes and what happens with the vascular system during the winter when they’re dormant, too,” she said.

No Comments

Leave a Comment

Only registered members can post a comment , Login / Register Here

Read previous post:
Videos: This Week in Duluth Snowy Owl Rescues Richard Hoeg spotted a snowy owl on Duluth Harbor ice this morning and at first didn't think it was...