If you have ever hiked in the woods and been surrounded by the sight and smell of pine trees, you may have taken a closer look at pine needles and wondered how their shape, material properties, and surface wettability are all influenced by rainfall.
In Physics of Fluids, from AIP Publishing, researchers at the University of Central Florida are currently probing how well pine needles allay the impact of rain beneath the tree. Andrew K. Dickerson and Amy P. Lebanoff explored the impact of raindrops onto fixed, noncircular fibers of Pinus palustris, aka the longleaf pine, by using high-speed videography to capture the results.
“Drops impacting fixed fibers are greatly deformed and split apart,” said Dickerson. “As expected, the breakup of the drop and the force felt by the fiber is dependent on drop size and speed.”
Impact force and the shape of the resulting lobe of water also
Sept. 29 (UPI) — The needles of longleaf pine trees evolved to effectively shed water, according to a study published Tuesday in the journal Physics of Fluids, ensuring rain moistens the soil instead of clogging leaf pores.
“Our initial inspiration for this project was [to study] raindrop impact on pine trees,” Andrew Dickerson, professor of engineering at University of Central Florida, told UPI in an email.
Dickerson and his research partners wanted to find whether or not rainfall has influenced the material properties of pine needles.
“We began impact drops onto cantilevered needles, but quickly realized the physics was very complicated and that the simpler problem of drop impact onto fixed, non-circular fibers had not yet been tackled,” Dickerson said.
To tackle it, researchers set up high-speed cameras to capture high-resolution, slow-motion video of drops hitting the wedge-shaped needles of longleaf pines.
According to Dickerson, dozens of studies have looked