The Frog Pond #6: Liquid Trees
Or, lies about trees and truths about algae.
True Spring bursts in colours up and down the familiar forest path. Bright lilacs and snapdragons sprinkle the green blankets on either side of the path, and a brilliantly blue sky pokes through the budding canopy above. You don’t need any natural signs to make the right turn anymore: you are now a habitual part of the pond.
You find the frog pond maturing: Tadpoles have grown legs and lost tails; waterlilies prepare to open their flowers for the summer; and a long-legged heron stalks the shallow waters.
This month’s frog pond is choosing to be patient, even with itself.
Mist-erious knowledge
A crisp column of mist forms beside you, swirling but unnaturally restrained. This time, you must be the one to reach out to its mysteries.
Liquid Trees!
At the end of March, I saw a burst of quote-tweets around a tweet and article from Yup That Exists that covered the concept of “liquid trees” in urban areas as an alternative to planting trees.
The replies were full of “why not just use real trees?” and cries of these algae tanks as evidence of a coming green slime dystopia while, many quote tweets decried the article for misrepresenting the concept. So what’s going really on?
Buckle up; this is a wild one.
What’s a liquid tree?
The Yup That Exists article cites one source: World Bio Market Insights, a bio-economic news site, from March 2023. WBMI cites a United Nations Development Programme article from September 20211 and a Euro News article from December 20212. Both articles use the same quotes from Dr Ivan Spasojevic, a research member of the project with the University of Belgrade.
The UNDP article calls the project “the first urban photo-bioreactor in Serbia”, also called the LIQUID 3 or “liquid tree”3. It’s a single unit, placed on Makedonska Street in Belgrade, meant to help air purification and reduce carbon dioxide emissions where it is highly concentrated in urban areas.
Belgrade specifically is an important element of this project because it hosts 2 of the 10 dirtiest coal plants in Europe4, and Serbia has the highest rate of pollution-related deaths in Europe of 175 per 100,000 people5. According to the UNDP regional representative for Serbia, there isn't much room in Belgrade for new landscaping6. So this country and city is a great case study for trying new ways of cleaning the air in an urban centre. Urban centres account for 75% of CO2 emissions in the world7 while only 56% of the population lives in urban centres globally8.
The LIQUID 3 uses a 600-litre tank of algae to bind carbon dioxide and produce oxygen through photosynthesis. It’s also fit with a solar panel, bench, charging ports for public use, and lighting at night. According to Dr. Spasojevic, the LIQUID 3 can provide the same carbon dioxide scrubbing as two 10-year-old trees or 200 square meters of lawn9.
The single-celled freshwater algae used in the project is local to Serbia, can grow in tap water, and is resistant to extreme temperatures. Maintenance is minimal: The algae grows indefinitely with new water and minerals every month and a half, while the biomass created can be used as fertilizer10.
Algae cracked up to be
Algae has a ton of uses, and falls into two categories: microalgae (also known as phytoplankton) and macroalgae (as known as seaweed). Microalgae can be used as a bioreactor and as nutrition such as spirulina, chlorella, Dunaliella salina (a Vitamin C supplement and orange dye)11, and Omega-3 fatty acids12. Macroalgae can be used as a carbon negative crop for food, be made into agar, and used as an an energy source, fertilizer, pollution control, polymers, bioremediation, pigments, as well as a stabilizer in milk products13. From personal experience, macroalgae can also be used to freak out your friends at the beach14.
Yup That Exists: Nope, Not Like That It Doesn’t
But while all of this is great, there’s an important detail: There’s only one LIQUID 3, and has been since 2021. I couldn’t find any information about an expansion to the product. Dr Spasojevic talks about the project group’s interest in expanding the use of freshwater algae in Serbia, but not about extending this particular proof of concept15.
The YTE article from 2023 uses the term “liquid trees”, making it seem like there are multiple units in Belgrade, and states that it: “create[s] a liquid substance that mimics the properties of wood”. This is a bizarre way to talk about microalgae and seems to portray the project as some kind of cold-press juice of the forestry world. Algae and trees are very different types of organisms, and I don’t know what “properties of wood” is supposed to mean in this context, because it’s not the wood of a tree that photosynthesizes, it’s the leaves.
YTE also uses the term “cellulose nanofibers”, which the WBMI articles (again, their only citation) doesn’t use, and neither does the original UNDP article. Cellulose nanofibers are not the same as freshwater algae. At all.
So where did it come from?
YTE also claims that the liquid has “high strength and toughness”. I have no idea how that’s related to a tank of algae. There’s so much in this article that is both very confidently worded and comes from thin air, because it’s nowhere in the WBMI article, which talks about algae. I had to double-check multiple times that I wasn’t just getting the links wrong.
But the title of the YTE article includes the term “algae”! So they knew it was algae. Yet they never mention it in the article!
I could quote the entire article here line by line and explain why none of it has anything to do with the original UNDP research it’s based on. Seriously. They say the nanofibers (again… that’s not what it is) are highly conductive and can be used as batteries or solar panels. Skipping over the fact that it makes no sense to say that a liquid substance could be a solar panel (??), the conductivity part again comes from nowhere, and as we know from the UNDP article, the LIQUID 3 has solar panels, but they are attached to the tank, as an add-on, not part OF the tank.
It makes no damn sense… compels me though
Why make all of this up? Is algae not cool enough to write about, even though it’s in the title of the article? Or does the fear of “pulping trees” instead of planting them get more clicks in the SEO? Did an AI write this16?
YTE boasts a readership of over 1 Million on their website, as part of Bradford Media, a group of news websites about interesting facts and travel, university, and life hacks. The article is written by the owner of Bradford Media itself17, who also has 4 non-fiction books published through Simon & Schuster. So I’d assume this is the best content they make, given it’s written by the founder himself.
So where did this go wrong? Assuming in good faith that YTE didn’t decide to lie for seemingly no reason, where did they get all of this information? Isn’t it more effort than to just repeat the WBMI article that they link to? Or did they cite the article without actually reading it? But then how did they get the algae in the title—
The search for cellulose nanofibers
Cellulose nanofibers are a real thing, made from wood pulp. I searched some of the sentences from the YTE article to find where they got the information, but came up short.
Mostly I found articles from AFTER the YTE article copying its text, and spreading the information further. I did find 5 LinkedIn posts that came up for the YTE article phrase “a liquid substance that mimics the properties of wood”, posted before the YTE article, but it doesn’t appear anywhere on those pages, only in the google search preview. So I wonder if that article came up on LinkedIn somewhere and stuck to the preview text? Unsure, but none of the posts had anything to do with wood or algae.
Okay, so maybe YTE didn’t lift the exact wording of its sources, just the concepts! Onto a broader search of cellulose nanofibers and its applications. Nothing useful comes up for “cellulose nanofibers liquid trees” before the article was written. The claim that cellulose nanofibers are good conductors is easy to find and true (though more specifically this is about carbon nanotubes, one of its applications)18, but has nothing to do with algae.
So, to the best of my ability, I cannot find a record online of anyone talking about cellulose nanofibers and liquid trees in the same sentence before the YTE article.
Side note: Cellulose nanofibers aren’t green, like in the photo of the LIQUID 3. They’re white or clear19. And as a pseudoplastic, it exhibits thixotropy, "the property of certain gels or fluids that are thick (viscous) under normal conditions, but become less viscous when shaken or agitated"20. So they're not even a typical liquid.
The YTE tweet, which cites microalgae in the tweet but nowhere in the article, has over 58 Million views on Twitter.
Back to nature: The answer isn’t always “more trees”
So back to reality: LIQUID 3 could be an efficient model for processing carbon dioxide in urban centres. And trees, while incredibly important to both ecosystems and urban planning, don’t just thrive automatically. Trees in urban areas require a balance of nutrients, space to grow, staff to cut overgrowth, and a planning system to keep tabs on them, remove dead trees, etc. (Not to mention things like vandalism—old trees in my hometown’s historic park were vandalized last year through “girdling”, which can kill the tree without cutting it down. Though of course it’s not like the glass of a tank can’t break either!)
Trees aren’t a perfect solution for every square piece of land in a city and require careful planning to get right. That’s not to say trees shouldn’t be used! Trees are great! Love 'em! But they’re not necessarily being used efficiently. And in some areas, like highly polluted urban centres, trees may not always be able to survive21.
So while the LIQUID 3 isn’t intended to replace existing trees, and again there is no plan available online showing more will even be implemented, it represents a helpful tool in the urban planning toolbox for areas of dense population, little open space, and high levels of pollution that don’t have 10 years to wait for tree growth.
Misinformation spreads like roots
Because there was so much outrage over the idea of liquid trees as a design concept, it seems like no one’s noticed that the contents of the article just aren’t true, and come from (seemingly) nowhere.
This, in my mind, is why it’s so important to dig into sources, because it seems that most of tens of thousands of people reacting to the idea of the LIQUID 3 didn’t read the article, only the title (not a novel concept with social media consumption, I know) and those that did read further didn’t catch that the YTE and original sources were saying completely different, unrelated things.
Just tacking a source onto the end of an article does not a well-cited article make, but it sure seems to trick a lot of people.
And I understand why there’s already discourse! The political discussion of “should we be excited or outraged at the idea that we have a need for bioengineered solutions to pollution” is a far more tantalizing one than “why is this talking about wood pulp”. There’s a reason this article was written the way it was, with the title it had.
But (again, as far as I can find in my research) there’s only one LIQUID 3 in downtown Belgrade. It’s a cool research project, but since its installation in 2021, it has not become the arbor usurper. This is currently an eco-tourist attraction, not a global solution, and certainly not about to uproot your local elm anytime soon.
When I write these deep dive posts, I look for a topic I find interesting. The unintended side-effect of that is that when I find discrepancies, they frustrate me. I want to tell everyone look, there, the truth!
But ultimately the people who were upset about the idea of liquid trees and didn’t read the article weren’t really misinformed, because the title mentions algae even though the article doesn’t (other than the badly worded use of “alternative” in the title, that is absolutely scare tactics for clicks). And if they knew more about the need in Belgrade, or the use of algae, or the limits to what trees can accomplish short-term in dense urban centres—would they care?
I don’t think so, because I don’t think they’re mad about algae. I think they’re mad at the idea of brutalist green sludge cubes uprooting trees and creating an unnatural dystopia—and, on a bigger scale, I think they’re scared. Scared of climate change, the unknown, technology being used just because it can be, and scared of what the world will have to sacrifice in the coming decades.
Or maybe they just hate green sludge. I am not a mind-reader!
The truth is, I’m scared too. Not of LIQUID 3, but of the global problem we face and feel powerless against. But fear doesn’t mean an ignorant reaction is bliss. It’s easier to scoff at the weird green liquid than it is to read deeper and acknowledge the large truth about dirty coal and pollution mortality rates and the urgency we need in response. Easier than acknowledging the truth that our lives, our politics, and our centres of power need to fundamentally change to even attempt to mitigate the global implications of the climate crisis.
Because quote-tweeting “ugh, just plant more trees” will not save us22.
A word from a passing frog
It’s May!! A wonderful month!! A month free of snow!! Finally!!
Querying
More of the same for querying: Sent a few more out, and got a few more back.
Submitted: 103 (we did it!! I finally reached my goal of 100!! I got ice cream to celebrate!!)
Rejections: 66 (including Closed No Response and Withdrawn)
Active Full Requests: 3
Waiting on: 37
It’s been a wild 6 months, with plenty of stories to save for… one day! But for now, I’m so proud and relieved to reach my 100-queries goal. This book is the first one I’ve written that I feel truly proud of as a part of me, even months after finishing (usually the “oh god my writing is so embarrassing” impulse grabs me by now. Progress!!).
Now I can take things a little gentler, and just send out new queries to any newly-opened agents on my list that I’m really excited about!
Drafting
On April 17th, I decided to take a break.
Burnout is tricky. It tells you that you’re experiencing everything except burnout; that you’re lazy, or you’re just mismanaging your time, or you just need to work a liiiiittle harder, and then you’ll get over it. The last thing burnout wants is to be handled, so it obfuscates and guilts you instead.
So, after about 3 weeks of kind of knowing this was happening but resolutely ignoring it, I’m on a break. A proper one. No writing, no editing, nothing. It’s been about 18 months since I took a significant break, and everyone needs one once in a while! Especially with how drafting has gone recently. I’m not stuck on the plot (luckily!) but I am stuck on confidence. When I sit down to write, it can take hours to actually get words on the page. That’s a sign that the call (aka the burnout) is coming from inside the house (aka my brain).
I’m still reading and querying, but I’m focusing on rounding out my life (swimming more, eating well, enjoying non-word creative hobbies, etc) and giving distance to writing until I feel the pull again.
If you’re thinking “good for Sarah, I shouldn’t take one though”, this is my ask: Take the break. I don’t know a single writer who takes unnecessary breaks, but I know plenty that are unkind to their creative side. This is your “get out of writing free card”.
Reading
This month I started Forager: Field Notes for Surviving a Family Cult by Michelle Dowd (non-fiction memoir), and finished House of Salt and Sorrows by Erin A. Craig (YA gothic horror) and Our Wives Under the Sea by Julie Armfield (adult horror).
So far, Dowd’s memoir is a fascinating mixture of amateur foraging and religious cult psychology. She has a piercing voice that quickly gets to the heart of the tragedies of her childhood, without dipping into the melodramatic. I haven’t read many memoirs, but I highly recommend this one for anyone interested in either subject!
I’d been meaning to read Craig’s debut for months and finally had time at the same time as my library loan came in. It’s a retelling of the 12 Dancing Princesses, with a deadly family curse and set on a small island town. It’s fun and spooky and manages to balance a ton of characters really well (7 living sisters, along with their father, stepmother, suitors, townsfolk, and a spectre or two).
Armfield’s short novel was so much fun! I read it in two days! If you like eco-horror, sci-fi, and modern gothic fantasy all wrapped in one, you’ll love this one! I’m always so impressed by books that manage to be short, immersive, and insightful!
Next month I’m hoping to finish The Poppy War by R.F. Kuang (loving it so far at 35% in) and get to Our Share of Night by Mariana Enríquez.
Back to the pond
You let go of the mist. It holds its shape for a moment, then slowly seeps into the pond’s reeds. Where it towered, now a small green frog sits. After a moment of mutual surprise the frog hops toward the pond, then disappears under the murky water.
Storm clouds gather on the horizon. Time to go. There are responsibilities and joys to get on with. Sheets to take in, tea to brew, and words to write—or not. The world keeps moving, even if the frog pond stays quiet, strange, and weirdly wonderful.
But maybe you’ll turn left again, the next time you go walking.
Thanks for reading The Frog Pond! Subscribe for free to receive new posts and support my work. If you have any topics you’d like me to cover, I’m always happy to hear them!
Footnotes
1
The UNDP doesn’t cite anything but has quotes from a Resident Representative of the UNDP in Serbia, where the technology has been developed, as well as a municipal representative from Stari grad and an author from the research project, so it appears to be the originator of the content online since the UNDP was a partner on the project itself.
2
The EN article cites the same pollution statistics as the YTE article and has quotes from the same research author as the UNDP article.
3
In a way, “liquid tree” is a misnomer, given there’s no tree involved other than the idea of putting something green and organic on a public street to help with pollution.
4
https://www.env-health.org/wp-content/uploads/2019/02/Chronic-Coal-Pollution-report.pdf
5
https://gahp.net/wp-content/uploads/2019/12/PollutionandHealthMetrics-final-12_18_2019.pdf
6
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
7
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
8
9
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
10
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
11
https://web.archive.org/web/20081223081614/http://www.siu.edu/~ebl/leaflets/algae.htm
12
https://www.npr.org/2007/11/01/15823852/getting-brain-food-straight-from-the-source
13
https://en.wikipedia.org/wiki/Algae#Cultivation
14
Me, the Atlantic Ocean
15
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
16
I’m really trying to keep these as questions instead of statements to not accuse anything, but it really, REALLY smells like this article was AI generated. It has the hallmarks of AI: The title doesn’t match the content, the content comes from nowhere but sounds like it might be real and mixes up facts… I will let you draw your own conclusions.
17
As an aside, please do not reach out to this person on my behalf. I don’t want anyone harassed for my speculation. If you do want to help, I’d recommend sharing the original sources of the LIQUID 3!
18
https://pubs.acs.org/doi/10.1021/nn4060368
19
https://www.ojiholdings.co.jp/english/r_d/theme/cnf.html
20
https://pubs.acs.org/doi/10.1021/acs.chemrev.6b00225
21
https://www.undp.org/serbia/news/first-algae-air-purifier-serbia
22
I’m sorry that this is depressing!! It’s hard to talk about anything to do with climate change mitigation and not get existential. But while we have big, big problems, we also have a world full of researchers and activists and every day people trying to save the world. We just need the will to support them—or become them.
