Fast-growing bamboo has become established as one of the materials of choice for ethical clothing brands. It is also used to make alternatives to plastic-based homeware, such as straws, takeaway cups, and storage containers. Because it takes just four years to be ready for harvest, and doesn’t require pesticides, bamboo seems like a sustainable option, especially when compared with the likes of plastic or water-intensive cotton.
But there is more to the story of bamboo than first meets the eye. Let’s take a closer look at the eco-credentials of this crop to see whether bamboo really is a better sustainable option.
What is bamboo?
Bamboo is a species of grass, which is why it grows so fast. Native to tropical areas, it is mainly grown commercially in China. The woody stalks can be harvested after just four years, which is a bonus for growers as it is a crop that can quickly be replenished.
Bamboo has an extensive root system, which means it grows again after being harvested, without needing to be replanted. It is also naturally resistant to pests and diseases, making it an easy crop to grow organically, without the need for harmful chemical fertilisers and pesticides.
That extensive root system is also good news for the soil. Bamboo can grow where other crops can’t, including on steep slopes. Its roots help to hold the soil together and the densely clustered stalks can soften the impact of rainfall, helping to prevent erosion and landslides.
How is bamboo typically used?
In countries where bamboo grows naturally, it has long been used as a building material and to make furniture. As awareness has grown of the issues with many traditional fabrics, bamboo’s quick-growing, pest-resistant characteristics have caught the attention of both the fashion and homeware industries.
You’ve likely seen bamboo used to make everything from reusable coffee cups and picnic plates to super-soft leggings and t-shirts. Many fashion brands use bamboo in their eco-friendly ranges as an alternative to cotton or manmade fibres such as polyester or acrylic.
Around our homes, bamboo has also become increasingly popular as an alternative to plastic. As well as those reusable coffee cups, you may have seen the likes of bamboo straws, bamboo toothbrushes, or bamboo storage containers that can be used in place of traditional plastic Tupperware-style containers. It can even be used to make toilet paper.
Is bamboo sustainable?
With so many different uses around our homes and in our wardrobes, bamboo has big potential for the movement towards living more sustainably. But, as ever, things may not be quite as rosy as they first appear. To understand whether bamboo can really live up to its eco-friendly credentials, we need to take a harder look at how it is grown and how bamboo products are manufactured.
The raw material: Growing bamboo
Bamboo’s popularity may be part of its issue. With demand so high, there is a lot of incentive for farmers to grow bamboo in place of other crops. When a single crop is grown intensively like this, it is known as a monoculture – and monocultures are bad news for biodiversity and healthy soil. They also displace wildlife from their natural habitats.
Growing bamboo as a monoculture isn’t great news, but what is worse is that the demand for bamboo is causing farmers in China to clear natural forests in order to plant more of this popular crop.
Canopy, the organisation that campaigns to protect the planet’s natural and ancient forests, say that intensive growing of bamboo has been linked to deforestation. Any benefits to the environment from bamboo’s quick growth are lost if natural forests are cleared to make room for bamboo plantations. An unsustainable way of growing a crop viewed as sustainable.
Well-established natural forests are vital to the future of the planet. As well as housing over half of all land-based animals and plants, forests act as a carbon-sink, storing carbon dioxide instead of releasing it into the atmosphere. Their loss is a big blow to efforts to reduce greenhouse gasses and slow the effects of climate change. So, bamboo grown on land that has been cleared of natural forest is a long way from an eco-friendly option.
Finally, with almost all commercial bamboo grown in China, questions have been raised about the use of chemicals and pesticides. The Chinese government provide generous incentives to farmers to grow more bamboo. But there is little environmental regulation. Although bamboo can be grown without the use of harmful chemicals, farmers under pressure to make money may decide to use them anyway in order to obtain a higher yield.
That’s not to say all bamboo is bad. But it matters where and how it is grown. Canopy advise that bamboo can be an environmentally friendly option when it is grown on land that was cleared long ago or that can’t be used for other crops.
As a consumer, complicated supply chains mean that it can often be difficult for us to know how the bamboo used in the products we buy is grown. Fortunately, certification schemes are in place which can help inform us as to the transparency and legitimacy of the suppliers or growers involved in the sourcing and manufacturing story of the end-products we buy.
Look out for bamboo which is certified by the Forest Stewardship Council (FSC) which means it has been sourced from forests that are managed according to the FSC’s social and environmental standards. You can also opt for organic bamboo, to be sure it has been grown without the use of chemicals that harm both people and the planet.
How is bamboo fabric made?
Let’s assume for the moment that the bamboo used to make our favourite leggings is organic and comes from well-managed plantations. The raw materials are therefore fairly sustainable. But how about the manufacturing process? How does the woody bamboo become a soft fabric?
There are two ways to turn bamboo into a fabric that can be used to make clothes. In both cases, the aim is to break down the woody plant fibres and then spin them into yarn. This can be done either mechanically or chemically.
Mechanical bamboo fabric
Bamboo fabric made through the mechanical method is sometimes known as bamboo linen or bast (although bast can be made from other plants too). As the name suggests, this method uses mechanical methods to crush the bamboo and extract the fibres, which are then spun into a yarn.
Making bamboo fabric mechanically avoids the use of harmful chemicals and is a non-environmentally damaging method of making material for clothes. But the process is more expensive than using chemicals and the resulting fabric isn’t as soft, coming closer to linen than cotton in texture. As a result, fabric made from mechanical processes makes up only a tiny fraction of the bamboo available for clothes.
Chemically manufactured bamboo fabric
The vast majority of the bamboo clothing on the market is made from bamboo viscose (or rayon) instead of bamboo linen. Silky, breathable, and super-soft, bamboo viscose is a lovely fabric to wear. But the process used to extract cellulose from the woody bamboo stalks is rather less lovely, involving a number of harmful chemicals.
Bamboo viscose is made in the same way as any other viscose fabric. First, bamboo is turned into wood pulp by soaking it in sodium hydroxide, a harmful chemical that can cause burns and is toxic when inhaled.
The wood pulp is then treated with sodium disulfide. This toxic chemical has been linked to serious health issues, including psychiatric issues, heart disease, and cancer. It doesn’t just affect those working directly with it either – emissions from viscose factories have been found to cause health issues for local populations too.
Once treated, the wood pulp is dissolved in sulfuric acid to make a thick, viscous liquid, which is formed into fibres by a spinneret. The fibres are then spun into yarn.
As well as being harmful to human health, the chemicals used to manufacture bamboo viscose have a negative impact on the local environment. The process uses a lot of water. In traditional viscose manufacture, the water is released back into local waterways. If it isn’t properly cleaned first, this wastewater can contaminate rivers and lakes, causing issues for aquatic life.
Can bamboo fabric be sustainable?
The mechanically-made bamboo linen doesn’t cause issues for the environment, so it can be an eco-friendly choice, as long as the raw materials are responsibly grown. Unfortunately, it is hard to find clothes made with this type of bamboo fabric. Bamboo viscose, on the other hand, is easy to find but its harmful chemicals are a nightmare for both the environment and for the health of the people who make it.
There are some alternatives to traditional bamboo viscose that are growing in popularity. Lyocell (sometimes marketed under the brand name Tencel) is one which has potential. It uses an organic compound called N-methyl-morpholine-N-oxide in place of the harmful sodium hydroxide and carbon disulfide, making it less toxic for the environment. Lyocell is also manufactured in closed-loop factories, which work to reclaim and reuse water and chemicals, rather than releasing them into the environment.
Lyocell won’t necessarily be made with bamboo – like viscose, this material can be made from any woody plant. Eucalyptus and beech trees are both used to make Tencel. But you can find lyocell that is made from bamboo.
Bamboo’s potential as a sustainable crop might mean it is preferable to other woody raw materials that don’t grow as quickly. As long as the raw bamboo is grown responsibly, bamboo lyocell can be a good option for environmentally friendly clothing.
So, can bamboo clothing be considered an eco-friendly option? The answer is a qualified yes, but you’ll need to look closely at how it is sourced and manufactured to assess the legitimacy of the ethical values to get a more transparent picture around things like growing conditions and workers rights.
Fortunately, many ethical brands are aware of the issues and publish information on their websites explaining how the bamboo fabric used in their clothing is made. If your favourite brand isn’t being open about this, it is worth getting in touch with them to ask – if they know that their customers care, they are more likely to put closer scrutiny on their bamboo supply chains.
What about bamboo homeware?
Bamboo is used in lots of different products, from furniture to flooring. Each use case will have a slightly different manufacturing process, but broadly speaking we can separate them into products that utilise the woody bamboo in a close to natural state, and those which use reconstituted bamboo. We’re concentrating on smaller household items in this article – things like kitchenware and toothbrushes, rather than furniture or building materials.
In some products, including bamboo toothbrushes and straws, the bamboo looks recognisably woody. In these products, the bamboo will sometimes have undergone a carbonisation process to form a harder surface layer that makes the bamboo more durable and waterproof. The process uses high temperature and pressure, so it does require energy. Not every bamboo wood product will have been treated in this way.
The bamboo is then cut to the desired shape, sanded, and usually treated with a food-safe coating such as wax or vegetable oil.
So far so, good. There’s not a huge amount of processing involved in these items. It is worth being aware that they aren’t usually designed to have a long lifespan though. Toothbrushes, by their nature, only last a few months. How long a straw lasts depends on how well you look after it, but generally you’ll be looking at about a year or two of use – much better than a single use plastic straw, but it isn’t an item you’ll keep for life.
The big advantage of using bamboo for these items is that it is biodegradable. Since they often replace plastic products in our homes, items made from bamboo wood can be an environmentally friendly choice. Just look out for bamboo that is FSC certified so that you know the raw materials are responsibly sourced.
Longer-lived small homeware items, such as coffee cups, phone covers, and food containers, are usually made in a different way. You can tell this when you hold them – they don’t feel like natural wood, but more like a cross between wood and plastic.
It probably won’t come as a shock to find that there is a bit more processing involved in making these items. But you might be more surprised to find they aren’t even plastic-free.
Firstly, things like bamboo coffee cups aren’t made directly from raw bamboo. Instead, bamboo fibres are ground into a powder, which is combined with corn starch to form a paste. This paste is then mixed with melamine resin – a kind of plastic made from combining melamine, an organic compound, with formaldehyde, a chemical used in many different manufacturing processes (although possibly best known for its use as a preservative in funeral homes).
Melamine resin isn’t biodegradable, so once the bamboo powder has been mixed with it, the resulting item isn’t biodegradable either. And it can’t be recycled.
You might argue that the coffee cup is at least reusable, which makes it more sustainable than disposable coffee cups, many of which can’t be recycled either and have plastic lids or stirrers. This is true. But some worrying research by German consumer group Stiftung Warentest might mean you still want to find another alternative to bamboo for your reusable cup.
Melamine resin is generally considered safe if kept at temperatures under 70° Celsius. But coffee cups are regularly filled with hot liquid. Researchers from Stiftung Warentest wanted to see how this affects the chemicals that make their way into our drinks.
They looked at 12 different bamboo coffee cups, testing them by filling them with a hot coffee-like liquid and then analysing the fluid to see if any chemicals leached out of the cup. They repeated this seven times.
Their testing detected high levels of melamine in the liquid in 7 of the 12 cups, and noticeable levels in a further 4. Some of the cups also released formaldehyde. Only 1 cup didn’t release significant levels of harmful chemicals.
This is a problem, because both melamine and formaldehyde are thought to be harmful to human health. Melamine may cause bladder and kidney issues, while formaldehyde can irritate our airways and lungs.
It is worth noting that the researchers kept the liquid in the cups at 70° for two hours, which is far longer than the average cup of tea or coffee stays hot, unless the container is well-insulated (which bamboo cups usually aren’t). They also used a coffee-like liquid, rather than actual coffee. So, the levels of chemicals that are released under normal usage might be quite a bit less than was found by their trial.
Still, if bamboo cups and food containers aren’t biodegradable and have also been linked to potential health issues, it may still be wise to steer clear and opt for a different form of reusable coffee cup. There are other options out there, including glass or metal containers, and insulated metal cups, which may be a better choice.
So, is bamboo better? The final word
Although we’ve ended on a cautionary note, the picture certainly isn’t a bad one for bamboo. Organic bamboo from properly-managed plantations can be a sustainable raw material. While there are issues with bamboo viscose, bamboo linen and bamboo lyocell/Tencel are both good options for environmentally friendly clothing. And it makes a great alternative to plastic for common household items such as toothbrushes and straws. Just avoid products made from bamboo mixed with melamine resin – and raise questions with anyone who tries to sell you these as a biodegradable item.