Our Cities are Slime Mold, Can We Zone for Something Better?

Slime mold is an informal name given to several kinds of unrelated organisms that can live freely as single cells, but aggregate together to form multicellular reproductive structures. When they band together they pass resources around in vein like structures. They were classified with mushrooms for a long time, but they are not mushrooms. However, like mushrooms, they’re heterotrophic, meaning they eat stuff. Heterotrophic is the opposite of autotrophic. Plants are autotrophic – they make their own food. Humans are heterotrophic, we eat stuff we harvest from our environment.

San Francisco Bay Area from space. Whiter areas are denser.

Watch the first 30 seconds of this time-lapse video of slimemolds and mushrooms in action. You’ll be amazed.

Human cities are basically like slimemold. A bunch of individual organisms (people) band together to distribute resources, harvest more and reproduce. What could be better?

Well, plants, plants are better. They are way bigger, more organized and advanced evolutionarily speaking. They create the forest, they are the trees: the upper, middle and lower canopy. The slime mold lives on the forest floor, off of the detritus of the plants.

Clearly humans should aspire to be more like plants in our quest for a sustainable future. We should build up, supply our own food, energy and water. So when will our zoning laws account for this? In California, birthplace of the bio-mimicry movement, we are still pondering zoning increases to just 4-5 stories in many cities like Santa Cruz. Even San Francisco’s zoning is currently 70% low density residential, 1-3 stories. 4-5 stories is certainly progress over the current paradigm, but it is still just growing the slime mold, not evolving as we must.

Why not 20 stories? 50? 100? There are obviously impacts of structures this large, namely water, garbage and parking, but what if the zoning law only allowed them if the highest sustainability standards were met?

For example, if the standard zoned height with a traditional building is 5 stories, allow a building that is water neutral, to be 15 stories. With height bonuses that significant, the math could actually add up for a developer. 10 extra stories could mean enough units to invest in a small, on-site recycled water system. Or even a building water condenser, to supply drinking water to residents out of thin air.

Larger structures like this could have more modern, systematic approaches to garbage as well with chutes for recycling, landfill and compostables designed into the building. Perhaps there is a plastic melting machine in the basement or a centralized composting system for biodegradables. A 25-50% reduction in waste collection could be another eligibility point for a larger building.

We already know that energy usage is much lower in multi-story structures. Heat rises from lower stories keeping upper stories warm in the winter. Higher buildings get more natural light and air circulation as well.

Parking is another sticky point, but if these large buildings are only zoned along or near planned public transportation corridors, and residents agree to use 0-1 cars instead of 1-2, we may again find the efficiency saving we need to justify it.

Finally, there is the challenge of affordable housing. In San Francisco, some county supervisors have even proposed that 30% of new developments be required to be affordable. That would mean that a 30 story building would need to offer 10 stories of housing at below market rate…

Is this affordable? Affordable to who? Certainly not the developer. Any new development is affordable to someone, otherwise it wouldn’t get built in the first place, and if said new development houses humans in a highly sustainable way isn’t that enough? Look at Tesla. They had to start with a luxury vehicle so that someone could compensate them enough for the new technology and engineering that went into creating a sustainable electric motor-coach. In 2016 they will launch the Tesla 3 for $35K and break into the mass market. So why would we excessively burden developers that agree to meet platinum level sustainability goals and push the envelope of housing technology?

Neighborhood displacement is of course an issue. It’s sad to think of whole neighborhoods of dyed in the cloth locals being displaced by affluent new-comers with no respect for place. Yet, if we’re willing to discuss 20+ stories, there should be room enough for all. After all, the same surface area is typically covered by 1-2 stories of residents today. Reduce the “affordable” requirement from 10% for the anyone, to whatever’s necessary to maintain existing residents (2 stories instead of 10) and everyone can be happy.

The current zoning updates happening in San Francisco and smaller cities like Santa Cruz are moving us forward, but not fast enough. They are incremental not evolutionary and we need to evolve to survive. Growing up, way up, is the right way to go. Especially if it goes hand in hand with net-zero water and 25-50% less garbage. It’s what nature has done with more advanced organisms. It’s the way we must go too if we’re too climb out of the slime mold.

Should Cities Zone for Taller Buildings that Meet Platinum Sustainability Standards?
Cities generally zone mid-density at 4-5 stories. If you support this motion, you’d be in favor of 15 or more stories if it meant radically more efficient water, power, garbage and parking standards.


  1. stephelinda says:

    The analogy fails. Either the author is ignorant of how natural ecosystems function or he has chosen to ignore the science. Slime molds, like their fungal siblings, break down and consume the waste of their “betters” (plants, animals). Without them, the waste would pile higher and deeper, locking up the earth’s resources so that nothing could live. Plants (autotrophs) organize resources (water, CO2, sunlight) to create food and oxygen. Humans do neither. We contribute nothing. Piling humans higher and deeper does not make us more like trees and does nothing to slow the inevitable demise of our species.

  1. […] post-nation state evokes all kinds of mental images: the shape of cancer, the networks created by slime mold, the international symbol for bio-hazard, or the logo of the fictional organization James Bond is […]

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