Photosource: www.passengerpigeon.ca
There’s never only one side to any story. Bamboo fabric is a classic example of a product that on the surface sounds very green. Bamboo plants grow incredibly quickly, can be planted in areas unsuitable for other crops, and rarely need any pesticides or herbicides. But issues arise with the way the fibres are processed and the fabric manufactured.
The most popular manufacturing process involves sodium hydroxide and carbon disulfide, both highly toxic chemicals to humans, and when released into the environment. The majority of bamboo fabric production takes place in China, a country not renowned for worker’s rights or environmental respect.
Bamboo fabric may have something to learn from another material that’s been produced quietly, with little environmental fanfare, for the last twenty years. Lyocell, sold as Tencel, is a fabric made from wood pulp. Tencel and Tencel blends drape well and are used predominantly in dresses and formalwear.
Tencel is manufactured in a proprietary process by the Lenzing Group, a international group of companies based in Austria. Lenzing describe themselves as “committed to the principles of sustainable management and very high environmental standards.” Tencel is manufactured in a similar way to bamboo fabric, but with important differences that may be the solution to green bamboo fabric manufacturing.
Here’s the recipe. First, take some wood pulp. Lenzing’s pulp mill uses hardwood – mostly birch and oak – from sustainable forestry plantations. The trees are chemically pulped and bleached. Lenzing say they utilise a closed-loop process and don’t use chlorine bleach to minimize environmental impact. However, Lenzing also buys wood pulp and their website becomes vague as to what conditions their suppliers’ wood pulp is manufactured under.
Next, the wood pulp is turned into fibres through a process called “solvent spinning”. Wood pulp is dissolved in a chemical called N-Methylmorpholine N-oxide (NMNO). The liquid is squirted through thousands of tiny holes in a spinneret, forming individual Tencel fibers. The spun fibres are washed, the NMNO is retrieved from the water, and it is purified, and reused in a 99% closed-loop process. NMNO can be toxic, but much less so than the sodium hydroxide and carbon disulfide used for processing bamboo. Small quantities of NMMO are actually produced in the body as a metabolite of several common drugs.
With a sustainable source of wood pulp, Tencel manufacturing has a much lower environmental impact than bamboo fabric. But despite considerate forestry practices, tree farms are more damaging to the ecosystem than growing bamboo. When natural forests are cleared for farms the local ecosystem suffers from the reduction in bio-diversity in the area. Bamboo is the slight winner here: it naturally colonises areas other plants find challenging and often grows with few other species for company, so it has less environmental impact when planted as a monocrop on a farm. Bamboo also grows much faster than hardwood trees, processing many times more CO2 from the environment than trees can.
Bamboo can be grown ecologically, and because of the increasing popularity of bamboo, companies are developing new, greener, ways to process the fibres ecologically, inspired by Tencel processing. Companies like Pure Bamboo are using new closed-loop processing methods, and hopefully more will follow.
Tencel is currently more eco-friendly to manufacture, and – depending on your standards – acceptably eco-friendly to grow. But bamboo fabric has the potential to be a true eco-friendly cloth.
For more on Tencel, What is Tencel on Wisegeek.
This post was written by one of Green Cotton’s contributing writer’s Brit.
Hey! Thanks for all the great info. I was browsing through a bunch of green websites and blogs and I came across yours and found it very interesting. There are a bunch of others I like too, like the daily green, ecorazzi and earthlab.com. I especially like EarthLab.com’s carbon calculator (http://www.earthlab.com/signupprofile/). I find it really easy to use (it doesn’t make me feel guilty after I take it). Are there any others you would recommend? Can you drop me a link to your favorites (let me know if they are the same as mine).
Dear Alex, thanks for your comment. I also like Daily Green, Ecorazzi, and Earthlab – great picks. I am also a big fan of the NY Times Fashion & Style section and Treehugger, and also read Ecosalon, Haute*Nature, Fabulously Green, Green Loop’s blog among others. I am also a huge fan of Gary Hirshberg and track his new organization Climate Counts http://www.climatecounts.org/. Speaking of carbon calculators – there are a lot out there and its interesting to compare and contrast. Another one I like is put out by the carbon fund http://www.carbonfund.org/site/pages/carbon_calculators/. Maybe that’s a good topic for a post in fact. Thank you! Cheers, Shana
Hi, I’ve been looking into bamboo fabric recently, and my understanding was that the pulp is processed into bamboo fibre through a process of mixing/crushing with a low impact chemical – caustic soda. Apparently according to the WWF the carcinogenic & environmentally unfriendly chemicals used in large scale cotton production have been linked to loss of biodiversity in cotton grown regions. Like you’ve mentioned, bamboo plants themselves have numerous benefits to the environment helping eliminate nearly 5 times the greenhouse gases and producing 35% more oxygen (as a byproduct) than the equivlent strand of trees, making it an efficient way of keeping te air fresh. So given all of this, over all isn’t bamboo clothing a benefit to consumers and the environment? Thanks.
Just copied this passage from a website i found. Does anyone have any comments. Thanks.
What chemicals are used in the processing of bamboo in fibre?
1) Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted and crushed
2) The crushed bamboo is soaked in sodium hydroxide. A common misconception is that sodium hydroxide is a harmful chemical. If used in a responsible manner sodium hydroxide has absolutely no effect on the environment and health of workers. It is routinely used in the processing of organic cotton into fibre and is approved by the Global Organic Textile Standards.
3) The sodium hydroxide is removed
4) Carbon disulfide is then added to the mixture to create viscose bamboo cellulose. There is a lot of money going into research and development to replace the carbon disulfide with more eco-friendly alternatives. N-methyl morpholine-N-oxide is non-toxic and eco-friendly and hydrogen peroxide, which is also non-toxic, may be able to be used instead.
5) The bamboo cellulose is forced through spinneret nozzles and hardened to convert the cellulose into bamboo fibre threads
6) The fibre threads are spun into bamboo yarn
Hi,
I really enjoyed this article. I’ve just begun my research in trying to figure out the environmental efficiency of using sustainable forestry plantations. I love trees and i find it hard to beleive that their could be a sustainable way of maintaining our natural tree forests.
so my question is in regards to the following line from above “despite considerate forestry practices, tree farms are more damaging to the ecosystem than growing bamboo. When natural forests are clreared for farms the local ecosystem suffers from the reduction in biodiversity.” …. whether you’re growing trees or bamboo or cotton wouldn’t you be clearing natural forests for farms whether you’re growing trees, bamboo or cotton??? Any renewable source needs farm space to grow…how is a sustainable tree forest any different from a bamboo farm?
Thanks!
Hi Sandi,
Good question. My understanding of the issue is that tree-cutting for cotton is very different from bamboo growing in primarily two ways: 1) bamboo (where cultivated) is a native plant grass to that area. Known as bamboo groves, which exist all across Asia, the bamboo is cultivated from these natural habitats (new areas are not cleared).
So you might ask then what happens after the bamboo is cultivated? Well, it turns out, that the second (2) reason that bamboo cultivation is not like cotton, is that it is the fastest-growing plant on Earth. Bamboo can grow six or more inches a day. In other words, it is more like a weed or a grass– growing very quickly and rapidly. Otherwise known as a renewable resource. Cotton on the other hand, as you may know requires a tremendous amount of water to grow, and unless organically grown, requires a lot of pesticides and is harsh on the soil. Since Bamboo is grown in its natural habitat and grows very quickly, all the other species (flora and fauna) can remain.
Interestingly, once bamboo has inhabited an area, it is very difficult if not impossible to get rid of it. See this quote from Wikipedia “Once established as a grove, it is difficult to completely remove bamboo without digging up the entire network of underground rhizomes. It can be removed manually, but if any leaves are allowed to photosynthesize, the bamboo survives and may continue spreading.”
Does this help answer your question? I hope others might chime in as well. If you’d like more information on the topic, you may want to check out wikipedia http://en.wikipedia.org/wiki/Bamboo#Growth
Sincerely, Shana
I understand it takes more than 1,100 gallons of water for commercially grown cotton while it only takes about 440 gallons of water for organic cotton. Do you know what the water requirements of bamboo are? I’ve read that bamboo requires a lot of water for new shoots, but once those shoots have grown into culms then the water requirements drop. I’ve also read that bamboo can process “dirty” water better than any other plant. It has been theorized that bamboo can actually help clean up polluted water sources.
Dear Monique, thanks for your excellent question! I am not sure on the water requirements, and partly it would depend on the size of the crop, but assuming we are comparing apples to apples, I do know that organic cotton is more conservative in its water use…..as to how much more conservative, I will need to research that question.
With respect to bamboo, I believe what you suggest is true in terms on not requiring a lot of water once that shoots have begun to grow. I know that it grows quite well natively in many areas (almost like a weed) so it is not dependent necessarily on man-made water sources to grown. However in the case of commercially grown bamboo, that would be different since companies are looking for speedy and efficient growth. With respect to dirty water too, I dont doubt that since it is almost like a weed. However I have not yet been able to identify a credible source on this so will continue to investigate.
In the meantime, some benefits of bamboo cultivation to consider:
* Grown without pesticides or chemical fertilizers
* Requires no irrigation
* Rarely needs replanting
* Grows rapidly and can be harvested in 3-5 years
* Bamboo produces 35% more oxygen that an equivalent stand of trees
* Is a critical element in the balance of oxygen and carbon dioxide in the atmosphere
* Is an excellent soil erosion inhibitor
These by no means make this plant a good fiber (for clothing) – these are just benefits of the plant itself. As soon as we move into the discussion of fibers and fabrics, we need to look at the processing component, and as we have written about in the past, that is the area of greatest concern.