An unexpected wood imposter has been gaining popularity, threatening the place long held by North American hardwood. By claiming to be more renewable than hardwood, bamboo, which is not a wood at all but rather a grass, has used the green craze to its advantage. The key question is, “How green really is this grass from Asia?”
Bamboo’s gain in popularity is not the result of it being a tested or proven resource. Many of the environmental and sustainability claims made about bamboo by marketers are not based on verifiable facts.
Bamboo definitely has a myriad of uses. It is used in construction, flooring, furniture, kitchen utensils, crafts, and as a fuel. That’s not a question. The question is whether or not it is as green of a resource as hardwood.
The best thing that bamboo has going for it is its natural regeneration and rapid growth rate. The primary propagation method for bamboo is the sprouting of new shoots from rhizomes. Harvesting does not kill the bamboo plant as the rhizomes are underground. Though they require between four and seven years to reach the quality used for construction, new stems can grow to their full height within a year.
“Height growth of bamboo is as rapid as one foot per day to a height of as much as 130 feet, in as short a period as four months,” according to a study by Dovetail Partners, Inc, an independent organization whose focus is providing information about the impacts and trade-offs of environmental decisions, such as consumption and land use. “In one documented instance in Japan, 1.2 meters (3.9 feet) of height growth was recorded in a single 24-hour period!”
Bamboo does indeed grow much faster than hardwoods which take between 40 and 120 years to mature. However, assuming bamboo is green just because it grows so swiftly is not acceptable. The reality is that environmental impact does not begin and end at harvesting.
Unsustainable plantation management practices have created problems, such as erosion and a decrease in biodiversity, which begin long before harvesting.
“Bamboo expansion has come at the expense of natural forests, shrubs, and low-yield mixed plantations,” according to an article published in the July 2001 Journal of Forestry on the bamboo sector in China. “It is common practice to cut down existing trees and replace them with bamboo. As forestlands tend to be in hilly and mountainous areas with steep slopes, clearcutting has resulted in an increase in erosion until the bamboo becomes fully established, which typically takes two years. Natural forests in the vicinity of bamboo plantations have sometimes given way to bamboo as a result of deliberate efforts to replace them or because of the vigorous natural expansion of bamboo in logged-over forests. This process has also had a negative impact on biodiversity.”
A lack of oversight is a major concern for bamboo because the material used in the U.S. construction market is imported mostly from China, India and Vietnam, according to Dovetail Partners. There is nothing in place similar to Forest Stewardship Council (FSC) regulations, which is used for hardwood products, to ensure that the bamboo plantations use sustainable practices. This lack of regulations on bamboo management allows plantations to use chemical fertilizers unchecked.
“Although American importers often tout the environmental responsibility of their bamboo products, they generally have little information about, let alone control over, bamboo manufacturers, which are mostly Chinese-owned,” according to BuildingGreen, LLC, publishers of Environmental Building News and GreenSpec.
The origin of bamboo should also spark another question for an environmentally conscious public. How much energy is used to transport it from Asia?
Some have claimed that the efficiency of ocean transport balances out the distance that bamboo products must travel.
“The ocean freighters used for importing from China are relatively efficient at transporting goods compared with the trucks typically used for transporting domestic goods,” according to BuildingGreen. “The transportation energy of a Chinese bamboo flooring product may be comparable to a domestic flooring product.”
This comparison would work – if bamboo was grown and used only in port cities. However, those relatively efficient ocean freighters do not transport the bamboo from the plantations to the ports or from the ports to the job sites. Overseas shipping of bamboo creates far more greenhouse gas emissions than domestic shipping of hardwood, especially when the entire transportation route is considered. No matter what else is said, the energy used in the transportation of bamboo is going to be a hard issue to validate.
A shift from hardwoods to bamboo in construction could also shift the construction industry from relying on American grown and manufactured product to a reliance on foreign manufactured product, introducing a slew of economic questions that go beyond the scope of this article.
The energy concerns with bamboo go beyond just transportation. Bamboo also requires a great deal of energy in the manufacturing process, especially when used for flooring or a plywood substitute. The bamboo must be cut into strips before it is compressed with chemical based glue under high heat and pressure. The energy required for this far outweighs the amount of energy used to fell and mill a tree.
Other environmental concerns are scattered throughout the bamboo manufacturing process as well.
“Manufacturers use potentially toxic binders, finishers, and other chemicals; create lots of solid waste; and run equipment that may be dangerous and polluting,” said BuildingGreen.
A chemical often used in the glue for bamboo flooring is formaldehyde, which can emit noxious gasses into homes after installation. Glue content ranges from 3% to 20%. The manufacturing of bamboo flooring also results in a large amount of wasted product. Between 35% and 65% of raw bamboo material is used. The rest of the material is waste, and traditionally burned. When processing hardwood, however, practically every part of a log is used, down to the sawdust.
“In an era in which the environmental attributes of materials are increasingly questioned, and production details increasingly available, it is remarkable that a product such as bamboo flooring has been so firmly embraced by the green movement without vigorous attempts to determine what impacts result from its production and use,” according to Dovetail.
Part of the problem is that it is hard to compare wood and bamboo. Bamboo cannot be compared to hardwood for a number of reasons. It is not a wood, it is grass. It is not held to the same standards or responsible production that wood is. It has gained its “green” reputation through its wide acceptance by green building programs.
“Unfortunately, provisions of a number of green building programs, including the widely popular LEED program, are prescriptive in nature and based more on intuition than science,” according to a Forest Products Journal July/August 2008 article.
Bamboo needs to be held to the same standards that wood is before it is called green. “The key issue is that the only way to compare apples to apples on renewable products is to have the same expectations for both materials,” Dovetail said. “Today we expect forests to be certified by highly vetted international systems if they are going to qualify as being green. We should have no less expectation of all other renewable materials.”
There are still many unknowns with bamboo. Though some of the problems could eventually be reduced by implementing certification processes and standards, there are others that simply cannot be. The more you explore the hype behind the craze, the clearer it becomes that hardwood has a very green story to tell.
