Why is bamboo touted as such a powerhouse in the eco-friendly industry?
From straws and toothbrushes to flooring and textiles, bamboo appears to be the end all that be all as far as eco-friendly, sustainable materials go.
In this article, we will examine:
- Environmental Impact of Bamboo
- How it grows
- Harvesting techniques
- How it is processed
- What happens at the manufacturers?
- Are all bamboo products created equal?
characteristics of Bamboo
- bamboo is a self-generating natural resource – it is sustainable
- one of the fastest growing plants on the planet (it is actually a grass!)
- highly versatile and rapidly renewable
- can be harvested annually
- does not cause deterioration or depletion of soil
- the root systems are shallow, massive, fibrous networks that are very effective in holding soil in place
- prevents soil erosion
- versatile and adapts well, can grow on land not suitable for other types of agriculture
- it can thrive in problem soils and it grows so fast, it is efficient in repairing degraded land
- it is a great economic resource for members of the community in the region in which it grows
- bamboo can be used to build structures in the community
- locals can be employed for harvesting and processing bamboo
- does not require pesticides or man-made fertilizer to grow well
- bamboo contributes organic matter, increases fertility, microbial biomass and carbon content of soils
bamboo growing process
Let’s begin with a little background information, shall we?
where does it grow?
Most of the bamboo used in manufacturing is grown in Asia, however, it is able to grow pretty much anywhere in the world (except maybe Antarctica!)
Bamboo grows natively in warm, moist tropical climates, and warm temperate climates. This is not to say that bamboo can’t be found in any other climates, just that the bulk of bamboo can be found naturally in warm environments.
how does bamboo grow?
- individual culms (stalks) break through the ground at their full diameter
- they grow to their full height in a single growing season of 3-4 months
- during the growing season, each new shoot (new growth from seed germination that grows upward where leaves will develop) grows vertically with no branching out until the mature height is reached
- leafing out occurs from the nodes when mature height is reached
- the culm starts to harden the second year, continuing into the third where it will become fully mature
- fungus begins to form on the outside of the culm in years two to five
- five to eight years later the fungus causes the culm to collapse and decay
Because of the fungus developing and eventually overtaking the culm, bamboo used for manufacturing should be harvested in years three to seven (depending on the species) of its life cycle.
Harvesting process of bamboo
When bamboo is fully mature and ready for harvest, the culm is cut by a saw or machete just above the first or second node above ground level.
Bamboo harvested for manufacturing should only be of the best quality.
They should be free of rot, disease, splits, and cracks.
How do the mature culms get replaced after harvesting?
There are three ways that new bamboo plants can be started.
- From Seed: This is the least likely way for bamboo to be grown since bamboo plants seldom flower (which is a good thing because the bamboo plant dies after it goes to flower). The seedlings are grown in pots for a year, then transplanted into the main field where they will continue to grow and reach maturity.
- Rhizomes: What the heck is a rhizome, you ask? Well, according to the all-knowing source, Wikipedia, a rhizome is a modified subterranean plant stem that sends out roots and shoots from its nodes (see diagram above). In the case of bamboo, rhizomes are an underground culm that grows horizontally and sends out roots and shoots at the nodes. The shooting season takes place in the spring and early summer. As the shoot elongates, it develops into a new culm.
- Culms cuttings: This involves cutting a 2 to 3 year old culm into segments and burying them, or burying the entire culm. Roots will begin to grow at nodes (junctions where branches meet the stem), and will eventually send new shoots to the surface.
So far we have learned, where bamboo grows, how it is grown, how it’s harvested, and how it is sustained.
Let’s turn our attention to after the harvest.
What happens to bamboo during processing?
Depending on the product being manufactured, bamboo undergoes different processing techniques.
Manufactured Bamboo Flooring
- mature culms are sliced into strips
- outer skin and nodes are removed
- bamboo strips are boiled in a boric acid or lime solution to remove starch and sugars
- it is then dried and planed
- in the lamination process, a chemical called urea-formaldehyde (UF) is used as an adhesive
- UF resins emit volatile organic compounds (VOCs)
- bamboo products that do not use UF are available
- heat is used as an adhesive instead
- the cured boards are then planed, sanded, and milled
- an ultraviolet curing lacquer is then applied to the boards
Mechanically Produced Bamboo Fibre
- the woody part of the bamboo is crushed mechanically
- a natural enzyme retting and washing process is used to break down the walls and extract the bamboo fiber
- retting is a process that uses micro-organisms and moisture on plants to dissolve or rot away much of the cellular tissues, allowing for the separation of fiber from the stem
- harsh chemicals are not used
- the separated fiber is then spun into a yarn
This method produces mechanically-produced bamboo fiber, which is NOT the same as bamboo rayon.
Well, what is bamboo rayon then, you ask?
Let me explain.
Rayon is a textile fiber or fabric made from regenerated cellulose (viscose).
Cellulose is an insoluble substance that is the main constituent of plant cell walls and of vegetable fibers such as bamboo.
Basically, bamboo rayon is a textile made from the cells of the culm.
How do manufacturers process the bamboo to obtain the cellulose?
The most common way is known as the viscose process.
- cellulose material (such as bamboo) is dissolved in a strong solvent to make a thick, viscous solution
- the solution is forced through a spinneret into a quenching solution where strands solidify into a fiber
- the solvent used for this process is carbon disulfide, a toxic chemical that is a known human
- it can endanger factory workers and pollute the environment via air emissions and wastewater
- the recovery of this solvent in most viscose factories is around 50%, which means that the other half goes into the environment
- chemicals such as sodium hydroxide and sulfuric acid are also used in the viscose process
The main takeaway from this is to treat bamboo fiber and bamboo rayon differently when you are looking at your product labels.
They are not the same and should not be treated as such. The viscose process is not environmentally sound whereas mechanically produced bamboo fiber is.
A more eco-friendly alternative to bamboo rayon is lyocell bamboo.
- similar to the viscose processing procedure, with two notable differences:
- the lyocell process uses less toxic chemicals
- closed-loop manufacturing process
- meaning all liquid is recycled and all solvents are captured and removed
- considered to be eco-friendly
This process is fairly new, so not a lot of companies are currently using it.
It does, however, seem to be a better choice than viscose bamboo when looking for clothing and other items that are made with bamboo fiber.
In my opinion, mechanically produced bamboo fiber is the most eco-friendly choice.
Although this fiber does have a down-side as it is not as soft or smooth as either rayon or lyocell bamboo fiber. So softer fabric is a trade-off for a more eco-friendly method for sure.
Now, let’s turn our attention to the bamboo processing procedure for utensils, toothbrushes, straws, and items such as those.
I am going to be honest here, this information was HARD to find. I spent many a day researching what the process is, and to be honest I am disappointed at the results.
I even reached out to a couple utensil manufacturers, but unfortunately never heard back from them.
I believe this information is very important since these products are popular and are used every day, so I will share what I discovered, even if I don’t feel it is complete.
Bamboo Processing for Utensils
Not all bamboo utensils are created equal.
Some bamboo utensils are hand-carved from a single culm, without the use of glues and adhesives.
Other utensils are made from the bamboo fiber in which adhesives are used.
Adhesives tend to break down, meaning the product is not as high of quality as one carved from a single culm.
As well, chemical adhesives could leach into the food that is being prepared by the utensils.
My advice is to look for companies that advertise their products are carved from bamboo culms.
Product packaging that does not mention this fact is probably using adhesives. These are just my thoughts, please make the best decision for yourself.
What we have learned
Choosing bamboo products over other materials seems like a sound plan for eco-conscious consumers. It is an overall sustainable resource that should be utilized.
However, with almost any product on the market, there is a buyer beware aspect as well.
Consumers have to do their due diligence when choosing bamboo products.
As the NRDC (Natural Resources Defense Council) states:
We recommend avoiding conventional viscose bamboo, and instead seek out
mechanically processed bamboo or lyocell bamboo as a greener alternative.
If you have any questions or comments or additional information on anything bamboo, please leave them in the comment section below. I would love to hear from you!