Raleigh’s costly leaf collection effort is also a really bad idea, scientist says | Opinion

Starting Nov. 12, city trucks will begin winding through Raleigh neighborhoods using huge vacuums to suck up curbside piles of leaves.

It’s a gargantuan task that can stretch through February at a cost of several million dollars. Last year, city crews collected 67,000 cubic yards of leaves – enough to fill three football fields 10-feet deep. It’s so large an operation that the city will phase it out next year in favor of having residents put yard waste in special carts and bags set out for weekly collection. Charlotte uses the bag or cart procedure for leaf collection, though some other cities still use vacuum trucks.

But scientists are increasingly saying that the whole process of raking and removing leaves is environmentally damaging.

One of the most prominent of those voices is Doug Tallamy, a professor of entomology and wildlife ecology at the University of Delaware. He says the City of Oaks should leave its leaves where they fall.

“All the nutrients that your trees used that year are tied up in those leaves and if you take them away every year you’re starving your trees,” he said. “And then we say, ‘Hey, our trees are dying!’”

Leaving the leaves in place is about more than feeding the trees. A blanket of fallen leaves is also a crucial winter cover for insects, which are an important food source for birds and play a role in pollinating trees and dispersing seeds. Tallamy said a recent study that focused on one square yard of fallen leaves found 2,000 insects come out in the spring.

There’s a growing awareness of trees as dynamic forces in nature and their leaf litter is part of a cycle that keeps nature in balance.

“Now we want to care for the things that trees do well. They are not just entities sitting there, they are important, they have really important roles in our ecosystem, so we want to favor that as well,” Tallamy said. “That’s new. People are just starting to think about that.”

The problem with leaf removal is really a problem of too much lawn. Fallen leaves left in place will kill lawns, but Tallamy said the best approach is to keep lawns to a minimum and expand plant beds and other natural areas.

“There are four things that every property needs to do if we are going to reach any kind of sustainable relationship with Mother Earth,” he said. “Support pollinators, manage the watershed, support a food web and sequester carbon. A lawn does none of these things, and we’ve got 44 million acres of lawn (nationally), so, yeah, I’m not a big fan.”

Tallamy is a big fan of Raleigh’s iconic trees – the oaks. “They are the best at sequestering carbon, they are the best at making food for birds, they have big root systems, so they are the best at managing the watershed, and they do have the longest-lasting leaf litter. So, yeah, they’re the best.”

Though there are many reasons to leave the leaves, Tallamy knows it will take time to persuade people to reduce their lawns and the raking that protects them. And the municipal collection of leaves will remain a fall service for years.

“If the township said, ’No, we’re not going to collect leaves anymore,’ there would be a big outcry,” he said. “So we’re trying to get people to do it individually and if all of a sudden there’s not enough leaves to collect, they’ll stop doing it.”

Those who do adopt a more natural landscape for their property are doing something in the face of climate change and alarming declines in birds and insects because of habitat loss, Tallamy said.

“Everything is declining and people feel there’s nothing they can do about it,” he said. “But my message is there is something you can do about it on your little piece of the Earth. Then they feel empowered. They feel good, you’re part of the solution instead of part of the problem.”

Next month the vacuum truck will roll across Raleigh, taking up the first round of fall leaves like so much debris. But slowly, it’s becoming clear that there’s ecological value in just leaving the leaves.

Associate opinion editor Ned Barnett can be reached at 919-404-7583, or nbarnett@newsobserver.com