Ease off the rake: Scientists suggest keeping fallen leaves where they land

Pollinators and the atmosphere benefit from an untouched yard

By Chloe Bennett

To the human eye, a yard full of autumn leaves is a kaleidoscope of brown, yellow, red and orange. More than sight, the distinct smell of decomposing leaves – or the feeling of the crunch underfoot – is a sensory experience unique to fall. Although some may relish the colors, others may disapprove of seeing their yard work smothered or take pride in a cleared lawn. 

What lies beneath the bed of foliage, though, is worth leaving untouched, scientists say. 

In a forest, fallen leaves fertilize the soil and offer habitat to pollinators and other wildlife. Many species of moth and butterfly overwinter in developmental stages among fallen foliage, nonprofit Butterfly Conservation states. Birds such as the dark-eyed junco may peruse yards for insects as many gear up for winter migration. 

Above ground, SUNY College of Environmental Science and Forestry pollinator ecologist Molly Jacobson noted, caterpillars can drop into fallen foliage to overwinter. “When those leaves are destroyed or moved from beneath trees it can leave them exposed, which means they could die from the elements or be eaten by predators,” she said. 

While some invertebrate citizens get a boost, the atmosphere also benefits from a leafy lawn. Carbon dioxide is released from the leaves as part of their natural cycle, but when bagged and hauled to landfills among other waste, they produce methane. Abstaining from a gas-powered leaf blower can also cut down emissions.  

It’s possible a too-thick layer of leaves could harm plants, the National Wildlife Federation states. A guide from the nonprofit suggests leaving 3 to 5 inches is beneficial, but advises not to pile the material atop plants. “They’ll suppress weeds, preserve soil moisture and naturally compost and return nutrients directly to the root zone of your plants as they break down,” naturalist David Mizejewski wrote. 

Those concerned with a tidy lawn can still rake their leaves and help pollinators, Jacobson said. Making leaf piles in designated areas beneath trees and in garden beds helps insects and soil enrichment. She does not recommend chopping the leaves by mowing, a practice sometimes used for lawn health, because it can harm the bugs and their habitat.