星期四, 十月 08, 2009

The Sustainability of Bamboo as a Material

Introduction

Bamboo is a type of grass of which there are around 1,200 species. It is one of the fastest growing plants in the world. As a material it is also wildly used in many different areas. Bamboo is Eco-friendly and sustainable which make it a popular material. And in many countries it is a tradition to use bamboo as handicraft or construction material. This paper researched the major uses, life cycle, major impacts to the environment and society and the advantages and disadvantages of this material.

Major Uses of Bamboo and Removal Quantity of Bamboo

Bamboo grows mostly in the East and Southeast Asia, also in Northern Australia, India, sub-Saharan Africa and the tropical regions of the Americas. Based on the species of bamboo, it could be used in agriculture, construction, handicrafts, transportation, micro enterprises and industry fields. This material is also used in culinary, medicine, textiles and musical instruments. Bamboo pipes are used to irrigate vast tracts of agricultural land. Bamboo could be used for pillars, post, stilts, rafters, roofing, flooring, walling, scaffolding and many other purposes. Its mechanical properties also make it an ideal material for earthquake resistant and emergency housing [1]. Its natural elegance and easy workability make it a choice material for handicraft. Micro enterprises make extensive use of bamboo. The incense stick industry in India has over 3800 production units that generate nearly US $400 million from domestic and export markets [1]. It is also an ideal raw material for many industries. The bamboo shoots industry in China earns US $130 million per year from exports [1]. It is used in Chinese medicine for treating infections and healing. Its shoots are edible. It is a suitable material for wind and percussion instrument. And two methods developed in China could process bamboo into fiber for fabric. The fiber of bamboo is also used to make paper in Asia especially in China and Japan. Furthermore, the computer hardware producer, Asus, use bamboo to make laptop outer casing [2].

The bamboo resource statistics are inconsistent, fragmented and scattered due to following reasons: systematic inventories of global bamboo resources have never been done. Consistent methodology and techniques have not yet been developed. Bamboo is often intermixed with other forest species or grows outside forests, making assessment more difficult. Most bamboo is harvested and traded locally without entering official statistical records. The term 'bamboo forest' often has different and incompatible definitions in different countries [3]. The estimate bamboo removals of China in 2005 is  1230000 kilo-tones, 9803 kilo-tones for Myanmar, 14615 kilo-tones for India,7320 kilo-tones for Nigeria, 1500 kilo-tones for Sri Lanka, 136 kilo-tones for Pakistan, 53 kilo-tones for Ecuador, 40 kilo-tones for Japan, 21 kilo-tones for Philippines, 13 kilo-tones for Chile. So the overall bamboo removals in 2005 are about 1263501 kilo-tones. The overall other bamboo product in 2005 is about 74977 kilo-tones. The overall bamboo removals in 2000 is 6268122 kilo-tones, in 1990 is 268390 kilo-tones. The overall other bamboo products in 2000 is 21541 kilo-tones, in 1990 is 12463 kilo-tones [3]. From these data we can see the use of bamboo is rapidly increasing shows a high demand of bamboo and its products. In order to satisfy the demand of bamboo the produce countries increased the planting area of bamboo. The total area of bamboo forest in 1990 is 23988 kilo-ha, in 2005 it is 36777 kilo-ha [3].

Life cycle of Bamboo

Bamboo starts with rhizomes, stems that grow underground and send shoots and leaves above ground. It takes four to ten years for young bamboo to mature. After that it can grow new shoots each year. As mentioned before bamboo is the fastest growing plant in the world. A bamboo plant can grow an average of up to 60 centimeters (about 23.6 inches), and certain species have been measured to grow as much as 121 centimeters (about 47.6 inches) in one 24-hour period [4]. Because of this fast growth property bamboo can be harvested on a regular basis without killing the plant, unlike trees which die after harvest [5].

After harvest bamboo will go through some different processes based on the products it supposes to become. If it is going to be used in handicraft then bamboo will be cut into small pieces. If it is going to be used as construction material such as flooring then more processes are required. For example the solid process which is used to make solid bamboo flooring. Solid is the process of turning round, hollow stalks of bamboo into flooring starts with cutting the stalks into strips. Then strips are milled to a consistent thickness and go into a process to remove and insects. Then the strips are covered with glue and pressed together. Using a combination of heat and pressure, the strips are bonded together [6]. There are other two kinds of bamboo flooring processes: engineered and strand woven. All these processes consume energy. Extreme pressure, heat and chemical are used during these processes.
For bamboo fiber, there are two ways to process bamboo into fiber for fabric. One is a mechanical process similar to the process used to process flax or hemp; the stalks are crushed and natural enzymes break them down further, allowing fibers to be combed out [7]. The other is use chemicals to break down fibers then extrude them through mechanical spinnerets just like the way rayon is made. The chemicals used in the process include lye, carbon disulfide and strong acids [8]. Also energy is consumed during these processes.

Most of the bamboo products are made in Asia. They are generally shipped by freighter ship from the source to North American or other places. Some bamboo products have quite long life cycles. Bamboo handicrafts and furniture could last for decades. Bamboo construction material could last for a long time. Some of them can be refinished to last longer. Bamboo products also can be recycled, and reused. After that they are sent to landfills, some of them could be used as fuel.

Major Impacts to the Environment and to Society throughout Bamboo’s Life cycle

Bamboo is an extremely diverse plant, which easily adapts to different climate and soil conditions. Because bamboo's fast growth rate, its carbon sequestration ability is better than most trees. Carbon sequestration means how quickly it can absorb carbon. Bamboo minimizes carbon dioxide (which is linked to contributing to the greenhouse effect and the depletion of the ozone layer) and generates up to 35% more oxygen than equivalent stand of trees. One hectare of bamboo sequesters 62 tons of carbon dioxide per year, much more than one hectare of young forest which sequesters 15 tons of carbon dioxide per year [9]. The average bamboo biomass ranges from 6.5 tons per hectare in Pakistan to 167 tons per hectare in China [3].

There are over 90 genera of bamboo with about 1200 species globally. Bamboo provides a habitat for many other life forms. The best-known animals dependent on bamboo are the giant panda and red panda. Several other mammals and birds live in a symbiotic relation with bamboo forests. Studies show at least 27 species of birds are considered to be associated with bamboo in the Atlantic Forest, 25 of approximately 440 bird species (about 6 percent) live in Guadua bamboo thickets [3]. Bamboo’s mass flowering happens periodically and often leads to an explosion of the rodent population, resulting in famine and social cataclysms in various parts of the world [3].

But in order to plant profitable bamboo many forest are being cleared. Though bamboo is good at preventing soil erosion and makes a good habitat for a large number of insects, birds and animals, there are other species relay on tree forests; replacing much of the tree forests with bamboo decreases biodiversity in the region [5]. Bamboo can be an aggressive invader of nearby forests and create a monoculture if not managed properly and newly planted areas can lead to problems with erosion. There are also concerns about the fertilizers and pesticides used in bamboo farm which leach into the ground and contaminate groundwater.

Long-distance transportation and manufacture of bamboo products result to energy consumption and air emissions. The chemicals used during the manufacture processes like urea, a type of formaldehyde, is a volatile organic compound which affects indoor air quality [10]. Bamboo products are bio-degradable so they will not affect the environment like plastic or metal when they are sent to landfill.
Besides the impacts on environment, bamboo has a huge impact on society. According to the International Network of Bamboo and Rattan (INBAR), 2.5 billion people in the world depend economically on bamboo in 1999. In 2005 the international trade in bamboo amounts to about US$2.5 million [3]. Vietnam-based Prosperity Initiative, one of the organizations which are now investigating bamboo’s impact on economic, believes it is realistic and achievable to bring 750,000 people out of poverty by 2020 depend on bamboo industry [11]. But there is not clear evidence that socially-responsible worker conditions exist for farm laborers or factory worker in Asian companies that produce bamboo products like bamboo flooring [10].

Possible Future Scenarios of Global Bamboo Use and the Implication for Society

Bamboo is widely used in many areas. It is light, biodegradable, cuts the carbon dioxide emissions during its lifecycle. Past data shows that the demand of bamboo is rapidly increasing. In order to keep up with the demand countries which produce bamboo will increase their bamboo planting area. This results to the growing stock of bamboo resources. China and India contributed about 80 percent of the total growing stock in Asia. Ethiopia and Nigeria contributed about 80 percent of the total of Africa [3]. More job opportunities will be provided to people in those countries, especially for population under the poverty line.

With the increase of bamboo planting area the carbon sequestration will also increase which could decrease the carbon dioxide and produce more oxygen. This could slow the speed of globe warming. But many tree forests will be cleared; the biodiversity of the deforested area will decrease. If the planting of bamboo is not managed properly some species lives in tree forest may in great threaten of extinction. Also if fertilizers and pesticides are used then they may leach into the ground and contaminate the soil and groundwater. If the demand of bamboo keeps increase eventually there will be a shortage of this material, the price of bamboo will increase. And people will look for alternatives to bamboo. Still bamboo is a more Eco-friendly material than to wood, plastic or other materials. The global use of bamboo material indicates that people and manufacturers start to pay more attention on environment. Bamboo will be used more and more in construction in the future, and bamboo fiber will be more widely used than now. It can also be used to build the outer casing of vehicles and other products. It can be part of an effort to prevent pollution in the future. An ecological engineering firm in Concord, MA, Sustainable Strategies has designed a bamboo plantation system that will essentially eat, drink and transpire away waste from a North Carolina piggery which could be used to solve the pollution problems caused by animal wastes [12].

Bamboo is a renewable resource which is not like oil, after harvest it takes several years to grow new bamboo. Because the bamboo planting area is limited so the production of bamboo will reach a peak in the future. But it will not decrease like peak oil. The production of bamboo could maintain in a stable rate. It consumption water during growth, and energy during manufacture processes and transportation, otherwise it did not consume any energy. And it could be used as fuel to produce energy after its life cycle. The shortage of water may affect the produce of bamboo. High population may result to decrease of the bamboo planting areas so those places could be used by people. Bamboo could slow the effects of global warming; some believe it could reverse the effects of global warming if planted on a mass basis. So it is not only profitable but also eco-friendly to plant bamboo.
In order to make bamboo more sustainable the chemicals used during its farming and manufacture processes; the energy used during manufacture and transport; its recycle and disposal; and the human resources involved during its life cycle all need to be taken into account. The farmer and manufacture need to consider greener technology to process bamboo.

If the produce of bamboo decreases due to high population, high consumption or protection of biodiversity, then people need to use less bamboo and try to reuse bamboo products. Mean while we can try to look for alternatives to bamboo.

Conclusion

Bamboo is an eco-friendly material. It is strong, light and renewable, growth fast and could be used in fields like agriculture, construction, handicrafts, transportation, micro enterprises and industry and so on. It absorbs more carbon dioxide than tree so it is a good solution to fight global warming. The bamboo industry has already supplied works to billions of people. It has large impacts on the environment and society. Though there are some disadvantages of bamboo like decrease of biodiversity, the energy consumes during manufacture and transportation, the chemicals used during the manufacture processes. Overall bamboo is a sustainable material.

References

[1] Bamboo Sector, [Online] Available at: http://investinmizoram.nic.in/foi/bs.htm
[2] [Natur.e] ASUS Bamboo Series, [Online] Available at: http://event.asus.com/notebook/bamboo/index2.html
[3] Maxim Lobovikov, Shyam Paudel, Marco Piazza, Hong Ren and Junqi Wu, World Bamboo Resources: A thematic study prepared in the framework of the Global Forest Resources Assessment 2005, Food and Agricultural Organization of the United Nations Rome,2007.
[4] Bamboo, [Online] Available at: http://www.bambooandtikis.com/bamboo
 [5] Tiffany Connors, Are bamboo floors really green? [Online] Available at: http://home.howstuffworks.com/home-improvement/flooring/bamboo-floors-really-green.htm
[6] Bamboo Flooring Lifecycle, [online] Available at: http://green.findanyfloor.com/bamboo/Lifecycle.xhtml
[7] Delia Montgomery, June 26th, 2008, Bamboo Fiber: Greenwash or Treasure? [Online] Available at: http://feelgoodstyle.com/2008/06/26/bamboo-fiber-greenwash-or-treasure/
[8] Michelle Nijhuis, June 2009, Scientific American Earth 3.0 special, Bamboo Boom: Is This Material for You?
[9] Why Bamboo, [online] Available at: http://www.bamboocentral.org/shareinrepair/whybamboo.htm
[10] Elle MacKenna, Is Bamboo a Sustainable Building Material? [Online] Available at: http://hubpages.com/hub/Is_Bamboo_a_Sustainable_Building_Material
[11] Rachel Oliver, February 16th, 2009, The CNN Wire, Bamboo may help fight poverty [Online] Available at: http://cnnwire.blogs.cnn.com/2009/02/16/bamboo-may-help-fight-poverty/
[12] Carol Steinfeld, January 25, 2001, Environmental Design + Construction Magazine, A Bamboo Future.

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