The Topsoil Question

 One of Dorothea Lange’s famed pictures of Dust Bowl Oklahoma. This is absence of topsoil, at its extreme. (Library of Congress)

One of Dorothea Lange’s famed pictures of Dust Bowl Oklahoma. This is absence of topsoil, at its extreme. (Library of Congress)

Like the preceding item, this one is a response to this recent video by James Fallows, on The Atlantic’s site. The writer, a PhD chemist in California, emphasizes another reason to be concerned about today’s mechanized lawn care industry:

There is another problem which you didn’t mention which is common to both the gas-powered and battery-powered versions – they remove the topsoil from the targeted area.

As you pointed out, they are usually operated by less-educated, often limited-English workers. Convincing them that removing the topsoil from my planted areas is a bad thing has, in my case, proven impossible; they just don’t get it. After creating flower beds at my office that cannot soak up water because the groud has become completely hardened, I’ve had to complain repeatedly, with no luck. My only option will be to switch gardeners, but I’m told that they all do the same thing.

Keep them away from living things!

Additional points the same reader sent in a follow-up message:

1) The only place I’ve thought that the use of leaf blowers might be reasonable is in large parking lots. But even there, the noise and dust argue strongly against that application. And a more-efficient solution is already available for large lots – sweepers….

2) From your demo clip, the sound of the gas-powered leafblower is noticeably louder. I think that the confusion might result from the fact that these machines are rated in terms of loudness, in db, whereas we also perceive sound power (i.e. pressure), which can be thought of as the sum of the loudness levels at each frequency. Because they span a much larger frequency range, gas-powered blowers produce much more sound power even though no individual frequency might be louder that the corresponding loudest frequency of the electric model. I believe that’s why rock bands started erecting ‘walls’ of speakers in outdoor venues – they get massive sound power without a significant increase in the db loudness….

3) There are potentially at least three separate sources of noise from all leaf blowers – the motor, the blower, and the moving air. I don’t believe that much effort has gone into minimizing the blower or air noise because gas-powered motors are so loud by themselves that the blower and air noise is moot. But as electric blowers gain acceptance, and the noise levels drop sharply, I suspect that the role of the blower and moving air will begin to be addressed, making them even quieter. This actually happened some twenty years ago – dishwashers intended for home use got a lot quieter over the course of just a couple of years as the internal plumbing was redesigned to eliminate noise. Thus, I expect that eventually the electric blowers will get even quieter, whereas that is unlikely for gas-powered blowers, so your sound demo probably represents electric blowers in their worst incarnation….

4) Regarding the alleged lower power of the electric models – the market will respond, just as it has in every other case of electric devices. There are now on the market super-powered electric blenders, fans, and even can openers. There’s no reason that manufacturers can’t make more-powerful electric blowers, and with battery technology (finally!) starting to improve, the amount of energy someone can carry on their back will increase correspondingly. And to my earlier point – if electrics take over the market, the attenuation of the electric motor and blower noise can proceed apace, further driving down the overall noise levels of these machines.

The obvious solution is simply to ban the gas-powered blowers. They aren’t wanted, they aren’t needed, and they’re too dangerous.

Thanks to this reader, and others.