Cool City Design: Stockholm’s Urban Forest Experiment

"“People really love trees already, especially in Stockholm and in Sweden. I don't think that's the problem really…. It's more a problem with civil engineers that are responsible for road construction""

Björn Embrén began working with the green infrastructure in the city of Stockholm in 1976, eventually rising to the position of City Forester managing around 5060 employees. He was plagued by trees, especially older ones, beginning to die along the streets and in the parks, which of course aggravated the growing city heat island effect. By taking away the cooling effect of an urban forest, Stockholm was becoming Barcelona in the summertime. Worse, much of the dirty runoff from city streets that used to be absorbed by vegetation was now flowing into the lake that provided all of Stockholm’s drinking water. The city needed trees, but they were dying. Embrén looked deeper. He began to study the microsphere.

“Soil for me is a substrate that will support life below the surface, support the life of the trees, support life for the microorganisms and mycorrhizae—everything that should be in the ground.”—Embrén

Embrén traveled Europe, attending conferences, meeting with soil scientists and forest specialists, and looking for solutions. He also researched methods used by the early builders of the city, and why trees seemed to be so happy in earlier centuries but not today. One idea he came across was biochar. In fact, that was how we first met, at the 3rd International Biochar Conference, September 12-15, 2010, in Rio de Janeiro. 

When Embrén tried biochar on the verges of city streets he was astonished by the result. After three years, trees that were planted at the start of his trials looked like they were 30 years old. In other parts of the city, he was used to seeing 30-year-old trees growing only as large as three-year-olds.

But there was more. Under the streets, the biochar absorbed rain and let it flow through large rock channels Embrén had constructed, or sponged it up in the biochar for slow time-release later. Nutrients were likewise retained and dispensed on demand to the roots of the trees. The compost and biochar mixes he made— 3 cubic meters of his biochar/compost fit into the void spaces between the stone but added nothing to the overall volume of 20 cubic meters of structural soil. If you want to try this, an easy-to-use spreadsheet to calculate the components required is available for free download. Designs for water inlets and aeration wells and PDF files of key reference texts are also available at stockholmtreepits.co.uk. 

To protect the freshwater lake, Embrén started to work with the Stockholm traffic department to take up roadways and sidewalks and underlay them with biochar. So much biochar was required, he had to look abroad to find more. Eventually, he persuaded city authorities to begin transforming municipal wood wastes. The woody organic waste from backyard branches and leaves, Amazon boxes, and paper trash of the citizens of Stockholm began to circle back to those same citizens as free biochar the city bagged and handed out to use in home gardens. Stockholmers then were able to directly engage in the excitement and esprit of fighting climate change without flygskammen or having to sit outside Parliament on Fridays holding up skolstrejk signs.

 

Greta Thunberg outside of the
Swedish parliament (Sveriges Riksdag), 2018.

“Politicians love it. It's a part circular economy and you upgrade something that was a waste, something usable… and now they can even get 6000 Krona [$540] paid for one tonne of biochar.”—Embrén

 

Embrén discovered more than just a way to solve for climate change, urban heat, storm and melt flooding, air pollution, water pollution, and municipal waste reduction. He discovered a way to engage people in the regenerative practices now required for their own collective survival.

“People really love trees already, especially in Stockholm and in Sweden. I don't think that's the problem really and most people just want to protect the trees…. It's more a problem with civil engineers that are responsible for the road construction.”—Embrén

Slide from Tom Miles, US Biochar Initiative

Embrén made the engineers listen. They were skeptical at first but eventually the proofs—in the many benefits Stockholm received—became undeniable. Stockholm won the Bloomberg Challenge and used the prize money to expand Embrén’s work. Other cities sat up and took notice. All across Sweden, and then in its Scandinavian neighbors, then in the EU and USA, old highways and sidewalks started getting replaced with porous, cool, biochar alternatives.

This idea could be coming to a street like yours soon. If it doesn’t you should complain to whoever is in charge.

References:

 

Embrén, B. (2016). Planting Urban Trees with Biochar. The Biochar Journal (tBJ). Arbaz, Switzerland. ISSN 2297-1114, pp 44-47.

Embrén, B. (2009). Planting Beds in the City of Stockholm, A Handbook. City of Stockholm.

Construction Industry Research and Information Association (2015). CIRIA 753: The SuDS Manual. CIRIA, London.

Trees and Design Action Group (2014). Trees in Hard Landscapes: A Guide for Delivery. TDAG, London.

 

Greta’s first leaflet. Translation: “We kids most often
don’t do what you tell us to do. We do as you do.
And since you grown-ups don’t give a shit about my future,
I won’t either. My name is Greta and I’m in ninth grade.
And I refuse school for the climate until the Swedish general election.”

 

 

Meanwhile, let’s end this war. Towns, villages, and cities in Ukraine are being bombed every day. Ecovillages and permaculture farms have organized something like an underground railroad to shelter families fleeing the cities, either on a long-term basis or temporarily, as people wait for the best moments to cross the border to a safer place or to return to their homes if that becomes possible. There are 70 sites in Ukraine and 500 around the region. As you read this, 40 Ukrainian ecovillages and 300 in Europe have given shelter to thousands of adults and children and are receiving up to 1400 persons (around 200 children) each month. We call our project “The Green Road.”

For most of the children refugees, this will be their first experience in ecovillage living. They will directly experience its wonders, skills, and safety. They may never want to go back. Those who do will carry the seeds within them of the better world they glimpsed through the eyes of a child.

Those wishing to make a tax-deductible gift can do so through Global Village Institute by going to http://PayPal.me/greenroad2022 or by directing donations to greenroad@thefarm.org.

There is more info on the Global Village Institute website at https://www.gvix.org/greenroad or you can listen to this NPR Podcast and read these recent articles in Mother Jones and The World. Thank you for your help.

---

The COVID-19 pandemic destroyed lives, livelihoods, and economies. But it has not slowed climate change, a juggernaut threat to all life, humans included. We had a trial run at emergency problem-solving on a global scale with COVID — and we failed. 6.95 million people, and counting, have died. We ignored well-laid plans to isolate and contact trace early cases; overloaded our ICUs; parked morgue trucks on the streets; and incinerated bodies until the smoke obscured our cities as much as the raging wildfires. The modern world took a masterclass in how abysmally, unbelievably, shockingly bad we could fail, despite our amazing science, vast wealth, and singular talents as a species.

Having failed so dramatically, so convincingly, with such breathtaking ineptitude, do we imagine we will now do better with climate? Having demonstrated such extreme disorientation in the face of a few simple strands of RNA, do we imagine we can call upon some magic power that will arrest all our planetary-ecosystem-destroying activities?

As the world enters a new phase of the pandemic, there is growing recognition that we must learn to do better. We must chart a pathway to a new carbon economy that goes beyond zero emissions and runs the industrial carbon cycle backward — taking CO2 from the atmosphere and ocean, turning it into coal and oil, and burying it in the ground. The triple bottom line of this new economy is antifragility, regeneration, and resilience. We must lead by good examples; carrots, not sticks; ecovillages, not carbon indulgences. We must attract a broad swath of people to this work by honoring it, rewarding it, and making it fun. That is our challenge now.

Help me get my blog posted every week. All Patreon donations and Blogger or Substack subscriptions are needed and welcomed. You are how we make this happen. Your contributions are being made to Global Village Institute, a tax-deductible 501(c)(3) charity. PowerUp! donors on Patreon get an autographed book off each first press run. Please help if you can.

Thank you for reading The Great Change.