Post #471: My Wawa proposal? Look behind the Jades shopping center.

I can’t believe this story still has legs, but here’s a summary of additional news coverage.

Here’s my proposed solution.  You’d like to have something at the back of the lot that blocks sound and light to the greatest extent possible.  You’d like to have something fill that alleyway to prevent it from becoming an attractive nuisance (e.g., a place for high-school kids to hang out.)  It would be nice if the results weren’t too ugly and required no maintenance.  Environmental benefits would be a plus.

You’d get that, less the environmental benefits, by replicating the wall behind the Jades shopping center.  The masonry wall reduces parking-lot sound.  The thick stand of bamboo blocks light, and provides some modest attenuation of sound.

This example is a little scraggly owing to it being a relatively thin stand of bamboo on a north-facing wall.  At the Wawa site, with a wall facing southeast, the entire face of the bamboo grove would be greener.

As the site is under construction, they’d have the opportunity to do this right, corralling the bamboo with a “rhizome barrier” to keep it from spreading.  If Wawa is now of a mind to put up a wall, the incremental cost of a rhizome barrier around  the entire alleyway area is the cost of ditching the rest of the perimeter to 3′, plus the cost of concrete to fill the ditch.

As wildlife habitat, in this climate, my observation is that bamboo is more-or-less sterile.   It doesn’t flower, produce seeds, or produce edible foliage.  The deer won’t even eat it, for goodness sake.  It crowds out almost all competing species.  (Seldom recognized, the leaf fall is toxic to many plants.  I found this out the hard way by using bamboo stems and leaves as mulch — don’t do that.)   It’s basically a toxic invasive exotic pest.

In short, the only reason to use bamboo here is to use one pest (bamboo) to repel another pest (drunken high-school students).

In terms of carbon sequestration, the literature is fairly murky, and mostly focused on harvested bamboo plantations, not a standing grove of bamboo.  My interpretation of the literature is that, in the long run, a standing grove of bamboo of the type shown above stores vastly less carbon than hardwoods would, on the same land.  Bamboo has short-run advantage because it grows fast, but in the long run, you accumulate much more woody biomass with tall hardwoods than with bamboo.

Just a quick calculation to check that.  The largest tree taken down at Wawa was a 42′ stump diameter maple approximately 70′ tall.  Using this publication (.pdf), extrapolating from their table, and realizing that about half the weight of green wood is water, I come up with an estimate of about 6 tons of dry wood, above ground, from that one tree.  Using bamboo pole shipping weights and some guesswork, I’d put the above-ground dry weight of the average bamboo plant of the type pictured above at about 8 lbs.  That would mean it would take about 1500 bamboo plants to equal the above-ground dry wood weight of that one tree.  The entire alleyway in question is maybe 0.05 acres.  At that density, you’d have almost one bamboo culm (stem) every square foot, which I think is at the upper bounds of being plausible.  So one large tree stored as much wood above ground as an entire alleyway full of closely-packed bamboo.  Clearly, the standing hardwoods store more carbon than the standing bamboo, per acre.