Suppose my town cancelled fall vacuum leaf pickup and disposal.
Would the fuel saved by that offset additional fuel burned to run mulching lawn mowers, to take care of those leaves, in-place?
Best guess: Yes. Every lawn in Town could get an estimated five additional mowings per year, for the fuel currently used to vacuum and dispose of residents’ leaves.
This calculation gets at the carbon footprint of fuel burning, only, not at the local air pollution effects, the labor required, machine wear-and-tear, noise pollution, and whatnot.
Not to mention the socioeconomics of lawn service users versus self-mowers. Which, near as I can tell, in my neighborhood, seems to break along age lines, corresponding to big-new-house lines. Here, newcomers (which almost by definition means persons living in a giant new house) seem more likely to have a lawn service than old-timers, who typically bought into Vienna before the tear-down boom barred purchase of anything but a big, new house if you wanted to move into Vienna. I’m still trying to work out how I can get a good empirical estimate of the fraction of TOV homeowners using lawn services.
For now, this is just an accounting of fuel used, the estimate of which embeds considerable (but reasonable) guesswork.
As far as I’m concerned, this calculation removes a nagging afterthought to Post 1821. Almost surely, mulching-in-place requires less fossil fuel use that than raking/blowing, followed by vacuum pickup and disposal at a remote location.
Finally, from an environmental standpoint, there are better ways to deal with your leaves. First, you can just leave them be, #leavetheleaves. Second you can rake them off the lawn, piling them up somewhere in your yard, to decompose. I think this is properly a form of “sheet composting”. Third, you can mulch the leaves, on your own property. Last — and perhaps not considered acceptable from an enviro standpoint — is the approach of trucking the leaf liter off to be pasteurized (hot-composted).
I don’t think this requires any more discussion than that. In the grand scheme of things, fall leaf vacuuming and disposal is not our worst environmental sin. But if it’s outlived its usefulness for most, why sin at all?
Details of estimate: A while back, I guesstimated 2000 gallons of diesel, for the entire TOV fall leaf collection and disposal effort. (I think Town staff did a better estimate, at some later date.) A gallon of diesel has more energy and more carbon than a gallon of gas. Call it 2400 gallons of gasoline-equivalent. Separately, I estimate that my wife gets 17 lawn mowings per year, on 2 gallons of gas. (Once/week average, over four months.) Finally, Vienna has about 5600 dwellings, but I’m guessing about 4000 single-family-home lawns. Put all that together, and you get (( 2400/2)*17)/4000 = ) five mowings per lawn per year, for the energy/carbon value of the diesel used to pick them up and truck them off. If you have a better estimate, I’ll cheerfully accept it.
