In grade school most of us were taught that changing leaf colors were the result of falling temperatures. But a British scientist is now adding a more complex explanation: the leaves aren't just turning colors because it's cold, they're changing because the trees are going to the bathroom.
Professor Brian Ford, president of the Cambridge Society for the Application of Research, believes leaf drop occurs in order to excrete waste products from the tree. In his research he found that shortly before leaves fall, levels of potentially harmful components such as tannins and oxalates in them increase.
"The levels of heavy metals in abscised leaves are also raised, and they are clearly there to be excreted rather than stored," he told the London Telegraph.
"In autumnal landscapes, when plants leaves turn red and brown and are suddenly shed it is important to bear in mind what is happening," he adds. "The plants are having their annual, well, excretion."
"It does, though, mean that the colouration of leaves in autumn will never seem quite the same again."
It also may give you pause the next time you are tempted to step on a crunchy leaf.