No matter how stumps are packed into a landfill, inevitably the awkwardness of their sizes and shapes creates unstable soil, and pockets of air underground can ignite during chemical process of decomposition. “It’s just a biological process,” says Friedrich, who has a degree in mechanical engineering. Decomposing stumps generate considerable heat. Walk across Shoosmith’s stump dump on any given day with a thermometer and you’ll find spots hotter than 200 degrees, Friedrich says.
Stumps are expensive to dispose of, especially those that are uprooted. Residential stump grinders work best when stumps are still in the ground, at least partially, grinding the exposed trunks into mulch. But once they’re out of ground, with all their gangly roots exposed, stumps become more problematic. Bob Thompson, director of public works for Henrico County, says it costs the county about $2,000 to dispose of a single stump that’s about 48 inches in diameter, for example.
And because of tens of thousands of uprooted stumps following the hurricane, people have a burning question on their minds: Where are those stumps going? Sure, yard debris can be churned into mulch. But stumps are another category. You can’t simply drop a stump into a commercial grinder and flip the switch.
Turning stumps into mulch is complicated. At Shoosmith, a crane with a $40,000 stump-splitting attachment picks up each stump, splits it and then drops it on the ground a few times to knock off the excess dirt. (Dirt on the roots ruins the purity of wood mulch, so it must be removed.) Once the dirt is gone, the stumps go through a grinder that shreds the wood, which is then sold to make retail mulch.
Typically, Shoosmith churns out 800 to 1,000 tons of mulch a day. It sells it for about $20 a ton. Shoosmith fetches $50 a ton for mulch colored to a more fashionable dark brown. The stumps mostly come from developers who’ve cleared a large number of trees at once. Residential stumps, unless there is a hurricane, don’t usually make their way here.
Then there are the environmental issues.
Until the early 1990s, stumps were most commonly dumped into designated landfills, or what the Department of Environmental Quality calls a construction, demolition and debris landfill, or CDD. These are known in the industry as stump dumps, even though they typically contain all kinds of natural, biodegradable debris — branches, limbs, tree trunks and building materials, for example. Unlike more heavily regulated municipal landfills (where household garbage is disposed) stump dumps don’t receive as much attention because the material is organic.
The state didn’t regulate landfills at all until 1972, and it wasn’t until 1988 that Virginia adopted comprehensive policies for regulating them. So there are old, inactive stump dumps throughout the area that the DEQ doesn’t even know about.
“It would probably be something that you just come across,” says Rob Timmins, the regional waste program manager for the state environmental department. “The biggest issue with a stumplike landfill is stability. They are bulky and because of that they are not very efficient in their space in landfills. They may require a little more attention down the road, especially if the soil falls into the voids.”
Stump dumps sometimes stand in the way of progress. In May 1999, the Virginia Department of Transportation found a stump dump directly in the path of the Route 288 extension in western Chesterfield. The dump had to be removed because the soil was too unstable to build a road over it. The two-acre stump dump created considerable delays in construction, and wound up costing the state an additional $4 million to have it removed. In all, there were enough stumps and debris to fill about 19,000 dump trucks, the highway department said at the time. Even today, Friedrich says, a contractor continues to filter and screen the soil that remains from the old dump in order to rid it of contaminants.
So what about the new stumps in your yard? During the hurricane cleanup, Richmond and Henrico are picking them up along with the other debris that residents place on curbs for pickup. Chesterfield isn’t picking up stumps, however. (The Federal Emergency Management Agency is reimbursing localities for 75 percent of the total cost.) Grubbs Disaster Relief, the Florida-based company that both counties and the city hired to handle the cleanup, is grinding up all of the debris — including stumps in Richmond and Henrico — and then trucking it to commercial mulchers. In Chesterfield, residents can dump stumps for $25 apiece at the Shoosmith landfill, says Charles Dane, assistant director of general services for the county.
A tip, however, for stump dumpers: Landfill operators generally don’t like the term “stump dump.” And it’s not because of their flammability.
“We’re a wood-waste processing facility,” Friedrich says. S