You can’t drive out to the forest, snag several large trees and put them in a wind tunnel to run experiments, but you can get a lot done with saplings.
A new, ongoing study involves experiments doing exactly that, which marks the first of its kind at that scale, and the first time living organisms were used in the Natural Hazards Engineering Research Infrastructure (NHERI) Wind Research Facility at the UF Engineering School of Sustainable Infrastructure & Environment (ESSIE) Powell Family Structures and Materials Laboratory.
It’s all part of a U.S. Department of Agriculture (USDA), National Institute for Food and Agriculture (NIFA)-funded project led by School of Forest, Fisheries, and Geomatics Sciences (SFFGS) Research Assistant Scientist Tania Quesada, Ph.D., and UF Agronomy Assistant Professor William Hammond, Ph.D., that is studying the effects of Hurricane Helene on the incidence of pitch canker disease in slash and loblolly pines along with water transport.
“The fungus that infects the trees is present throughout the Southeast — it’s a common pathogen and it also affects the pine industry because it comes with high mortality,” Quesada said. “It causes excessive resins that lower the quality of the wood.”
She later added, “It’s been kind of common knowledge or anecdotally (shared) that, usually after a hurricane or big storm there is an outbreak of pitch canker disease which is caused by this fungus.”
After a hurricane, there is an assessment of the immediate effects, like damaged buildings, felled trees, etc. Unknowns here include how much tree damage is done after the hurricane due to disease and water transport deficiencies that need time to bear out.
All the moving around can cause tension and damage within trees, affecting their internal water transport system in such a way to turn water into vapor, which leads to a problem similar to trying to drink through a straw that has a hole in its side.
“Trees can’t rebuild those pipes, and the only way out is to grow,” Hammond said. “So, a big question on our end for my lab is, a hurricane like Helene goes through, the trees are still green, but beside the pathogen, is there another hidden forest health consequence?”
The size of the UF wind tunnel allows for these experiments to happen at scale for the saplings. Once team members set up the trees, they ran experiments using three different wind speeds, adding periodic wind gusts that boost those speeds by 20 mph.
“They have all these sensors to get pressure on different parts of the fixed physical environment, but here, what we’re running to test is to use this instrument to get our trees to crash around as they would in nature, outside,” Hammond said.
Saplings went into the tunnel coming from different hydration conditions. For instance, some were kept under drought conditions, while others went in with two weeks of inundation.
They used three different strains of the fungus in solutions, along with a water control. After going through the tunnel, the saplings got sprayed with solution, placed in giant bags and taken to a greenhouse for 24 hours. After that, they got taken out of the bags and put into storage for weeks of observation, as it takes a while to see evidence of infection.
“Forest health usually means only stuff on the outside of the tree, which is a bit of a shame,” Hammond said. “It would be like if you went to the hospital and all they did was swab you and identify you as an organism, but they never took your pulse and they never took your temperature. What we’re doing as physiologists is looking inside.”
Photos and videos: NHERI Wind Test | Flickr
NIFA Project Award No. 2025-68016-44500
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