Bamboo is not a sustainable fibre. It’s a viscose.
Bamboo was once heralded as the sustainable fibre to polyester. Firstly, it’s not sustainable. And secondly, it’s a terrible alternative to polyester! It’s not just the feedstock that is questionable, the biggest concern is in the production process.
We think it’s a sustainable fibre because it’s farmed as a mono crop. Without the need for fertilisers or pesticides and with little water. Basically it’s a weed. Which grows super fast. Traditionally feedstocks for viscose have been soft wood trees such as beech and eucalyptus from boreal forests, depending on your manufacturing location. Sources in and around Northern Europe and Canada are typically beech, which take 12 years to saturate before they can be harvested. Bamboo on the other hand matures much faster, typically about 3 years. And requires less land per kilo. So it’s a very lucrative alternative to viscose. It’s also much less regulated in our current environmentally aware climate.
People are slowly becoming more aware that mono agriculture is not great for the soil. Regardless of whether or not it is organic. That said, in areas where wildfires have ravaged forests, bamboo can be a benefit as a it secures the soil in case of heavy rainfall, avoiding mudslides, and it can help rejuvenate the soil when it’s grown with other crops. Bamboo plants are nitrogen and phosphorous rich. But it is still a weed, and can be very invasive at that.
There are reports of bamboo farming contributing to deforestation and biodiversity loss. And you know that’s a problem when Netflix add it to one of their cartoons where the heroes come and rescue the pandas from the heavy machinery. With extra emphasis being placed on this particular episode of Rainbow Rangers for it being a baby panda about to be flattened. While the human driven deforestation has been noted as ‘moderate’ compared to other sectors. This is mainly down to not being able to attribute what is intentional and what bamboo has just taken advantage of. Naturally bamboo does reduce the vigour, diversity and biomass of other trees surrounding it. What with it being a weed and all! It is worth mentioning that there are more than 500 different types of bamboo and pandas only eat 45 of them. And at the stage before maturity. So while it’s unlikely pandas are being killed for bamboo, any sort of industrial farming hurts biodiversity if it isn’t farmed using agroforestry methods.
Which brings us on to sustainable forestry. There is a study completed in 2020 around the impact of bamboo on the Amazon rainforest’s tipping point to a dry savannah. This noted that in areas of widespread bamboo growth which was allowed to reach maturity at around 28 years, seed and die off; the tipping point of a dry savannah was earlier due to the die off creating a highly flammable fuel source. The study noted that no research has been done on the flammability of seedling bamboo, which if it was negative could have a devastating impact on the rainforest’s ability to regenerate. And while it’s tempting to say this points to using bamboo instead of trees, there is also a study that has shown bamboo benefits from human disturbances while surrounding trees suffer.
Image: Unsplash / Kazuend
First thing to note about viscose is that it goes through 2 production processes to be made into a viscose yarn. First it’s pulverised and made into paper like sheets which then goes to the fibre producer. It takes quite a lot of heat, water and chemicals to make a tree into a silky fibre. The factory in China I went to had a vat 3 stories tall and you could feel the solvents at the back of your throat. Now this is where we get into the really murky areas of traceability. Firstly, you’ve got to know if and how that water is cleaned before going back into source. If they give an example of 98% of solvents are extracted, I would ask would you drink that water with 2% solvents in? I would not. You can also make bamboo fibres from younger plants and extract individual yarns like peeling a cheese string (IYKYK!), but that still requires a solvent process to make it similar in handfeel like silk.
Some places in Europe and North America will say they are sustainable because they can extract energy from the heated water used in the production process. Technically yes. But it’s also an unintentional benefit of offshoring to Asia as we came up with all sorts of rules and regulations they had to follow, that didn't apply to ourselves. Such as water facilities being located 1 mile away from the production facility, losing the energy as the water is transported. I’m not sure we could say that makes us more sustainable when they followed rules we made in the first place.
Solvents have long been a contentious issue in the viscose industry and there are now many fibres being marketed as more environmentally friendly, such as Lenzing’s EcoVera (eucalyptus feedstock). There are other sources claiming non toxic solvents or food grade solvents. Still not something you would want in your waterways, for which even a 2% leak into reservoir in the UK would shut down production, and therefore water supplies to customers, for several days. (There aren’t any plants process bamboo in the UK, I’m just making a point! However Lenzing do have a plant here which is touted at the most environmentally viscose plant in the world. There are studies, I’m not just making it up!).
Marketing on bamboo is great, especially if you let customers fill in the blanks. Bamboo toothbrushes that have been whittled (for want of a better word) can be composted at home as any wood, if it’s not been painted. Bamboo viscose can not be composted. Technically it’s biodegradable, but everything biodegrades eventually! Currently there aren’t any scalable facilities focussing on the recycling of bamboo, probably because it’s not that well used. But if yarn suppliers are making it, there needs to be options to look at end of life in the same way that Spinnova are, and Lenzing with their Refibra yarns.
Bamboo is also no good as a sportswear fabric as it holds a lot of water, more than cotton. It only has anti bacterial qualities when it’s a bast fibre (the cheese string), the minute it’s gone into a solvent that naturally occurring quality has disappeared. You also can’t market it as a natural fibre because it requires human intervention to make it into one; so it can only be marketed as a man made fibre.
Viscose was invented to be an artificial silk. At the time of it’s creation in World War Two there was a reason of public good for it’s creation. Today, that same metric can’t be applied. It has been reported that the Higg Index has contributed to a dramatically smaller silk market. While the method of extracting silk is quite unpopular, mulberry trees necessary for the production, sequester more CO2 than bamboo. (one for one mulberry trees sequester 16 times more, but obviously a single mulberry tree takes up more space than a single bamboo so who actually knows?).
Those are all the facts. If you’re still keen on using a bamboo, make sure you’re using the bast fibre from a traceable and verified source. Verified means visit it yourselves and make sure your paperwork has your brand name on it. Ensure your contracts with your suppliers, if they’re buying the yarns on your behalf, have stipulations if it transpires they have bought yarns from unverified sources.
