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Cover of Engineering Advantage Magazine, Fall 2018 issue

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Cactus Keeper


Trevor Harding's Cacti

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Trevor Harding is very familiar with the downside of being an avid cactus collector.

"I probably have spines in my fingers right now," said Harding, with a laugh. "I find them all the time. I wear welder's gloves, and I use long tweezers and forceps that they use in surgeries, to try to hold the plants, but I still get spines constantly."

With dozens of cacti under grow lights in his campus office and hundreds more in the sun surrounding his Templeton home, Harding, the Materials Engineering Department chair, doesn't hide his hobby. What he jokingly refers to as "the Madness" -- he now has nearly 700 species of the succulent -- began shortly after arriving to teach at Cal Poly in 2007. On a camping trip to Death Valley, Harding was intrigued by a small spiny plant with vibrant purple flowers he noticed thriving in the heat. 

"We came across these plants called the Engelmann's Hedgehog cactus that were about the craziest thing I'd ever seen," he said. "Coming from the Midwest, I hadn't seen a lot of cactus, and I just thought it was so cool and wanted to know more. I got hooked."

Harding, who earned his doctorate in materials and science and engineering from the University of Michigan, is particularly fascinated by the plants' unique structure and design. He said the spines serve several functions aside from protecting the plants from herbivores.

"The spines primarily provide shade from the sun, which is seriously important when they are small juvenile plants," he said. "They also serve as condensing surfaces to help collect water from the mist and fog. Evolution has essentially designed these incredibly sophisticated and successful organisms. It blows my mind -- just really cool."

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