So, what’s the source of the stink?
“Everything we smell — from bananas to pine needles — comes from molecules, usually made of volatile chemicals, meaning chemicals that evaporate easily. The molecules evaporate from the food or flower and travel into your nose, where they bind with receptors in our nose.
The compounds that make the Bradford Pear tree's flowers smell are likely due to a type of chemical called amines, Dr. Eloy Rodriguez, a professor of plant biology at Cornell University, told Business Insider.
We come in contact with the smell of amines every day in the form of body odors, like under the arm pits.
The fishy odor produced by the Bradford Pear is likely a combination of two amines called trimethylamine and dimethylamine, according to Richard Banick, a botanical manager at Bell Flavors and Fragrances. Although perfumers know what chemicals produce the fishy smell (trimethylamine is often used an indicator of how fresh a fish is) they can't be certain what causes the odor of the Bradford Pear, said Banick.” [2]
Allow us to introduce you to our pretty little enemy, the Flowering Pear tree, which also goes by the names Callery Pear or Bradford Pear. Here’s a brief history of the Flowering Pear and our best explanation as to why your usual BYU campus stroll was interrupted by a horrifically rancid smell.
Scientists aren’t totally sure why this harmless looking tree gives off such a funk, we’re sure of one thing-- the smell has got to go!
“The scientific name for the trees is Pyrus calleryana -- that is, they're pear trees. The variety is native to China and Taiwan, and was brought to the United States in the early 1900's to be used in hybridization experiments to produce a more fire-resistant pear tree; this proved unsuccessful. However, in the 1950s it emerged as an alternative ornamental tree, and was utilized extensively in landscaping due to its innate resistance to cold, disease, drought, fire blight, and pollution (it's been described as a "near-ideal street-tree"). However, the trees do have one weakness -- they tend to damage easily in strong wind. (I say: bring on the thunderstorms!)...
The Callery pear, as the trees are commonly known, is characterized in the springtime by clusters of white flowers at the tips of their branches that develop in March. Pretty. And stinky.” [1]