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Ecological Functions of Bamboo

2011/02/23 | By CENS

Researcher at Taiwan Forestry Research Institute, Council of Agriculture

Bamboo belongs to the Poaceae (or Gramineae) family under the monocotyledons group of which most members have one cotyledon, or embryonic leaf, in their seeds. Grown bamboo has culms hardened as xylem which can be processed for economic use. Culms, referring to the hollow stems with nodes, are composed of vascular bundle which make culms look straight, but resilient in nature. Lack of the structure for making secondary growth makes bamboo grow most in height with little girth expansion. Grown bamboo isn't much wider than little shoots in girth because bamboo's growth is focused on lengthening of vertical cells rather than cell proliferation. Most bamboo cells are vertical and few are horizontal. So, bamboo is vulnerable for being “chopped off.” Comparatively, “easy process” is one of bamboo's advantages.

The compact stylish chair is made of multi-layer-pressed bamboo.
The compact stylish chair is made of multi-layer-pressed bamboo.

Structural Traits
Young bamboo shoot, which has rich starch, good taste, and delicate texture, is a popular ingredient for Chinese food. It's of high economic significance. As for processed industrial materials, most bamboo is processed before being fully grown or picked in wrong season, so most processed bamboo material is still composed of much starch granule and inclined to be eroded by bugs. That's another weakness of bamboo products. If the two problems of being vulnerable to be “chopped off” and “eroded by bugs” can be overcome, people will be able to make perfect bamboo material to earn consumers' trust and preference.

Growing Environment
There are around 80 bamboo genera divided into about 1,000 species. Among them, some 200 species of 20 genera are native to the Southeast Asia. Except Europe and West Asia, bamboo occurs in diverse climate around the world, from low plain to the 4,000-meter high mountainous areas in a wide latitude range covering hot tropical region, sub-tropical region, and the temperate zone. Bamboo forest accounts for approximately 22 million acres across the world, mostly in the humid tropical region and especially in the area between the Southern Tropic and Northern Tropic. Around 85% of the world's bamboo is found in Asia. In Taiwan, bamboo forest takes up 150,000 acres and the six indigenous genera of highest economic significance—Makino Bamboo, Green Bamboo, Moso Bamboo, Long-branch Bamboo, Ma Bamboo, Thorny Bamboo—account for 75,000 acres in total. Taiwan, China, and Japan are the world's major sources of bamboo. In these areas, bamboo is intensively used as food ingredient and industrial materials, closely integrated into people's daily life.

The bamboo-engraved “Happy Buddha” statue.
The bamboo-engraved “Happy Buddha” statue.

Growth Habits

In terms of growth habits, bamboo is classified into two categories: caespitose (growing in small dense clumps or tufts) and ungregarious (growing in groups that are not close together). The former adapts to the climate in the tropical region while the latter mostly occur in the temperate zone. Both grow in Taiwan thanks to the diverse climate on the island. It takes only 5-11 weeks for bamboo to become grown, and then it will make little increase in height or girth. Bamboo grows fast, at a speed of around 100-150 times higher than the fastest-growing trees (like White Popinac, Montanahan, and Poplar which become 2-3 meters higher every year). It takes a much shorter period of time for bamboo forest to grow and renew than common woods.

Generally, it takes only four years for bamboo to become grown-up for economic use. The saying, “Raise bamboo for three years and pick it in the fourth year,” well indicates a four-year life cycle for the bamboo planted for economic use. It's the means to ensure endless supply of bamboo material. In Taiwan, forest is important for making soil and water conservation in regard of the steep mountain, rushing rivers, frail soil, and focused torrential raining season on the island. For forest resource conservation, the government announced prohibition on logging natural woods in 1992, and Taiwan has then relied on timber import to meet 99% of the island's annual wood demand. If well managed, the bamboo forest with a life cycle of four years could serve as a wood substitute resource and it will raise the ratio of self-supplied wooden materials in Taiwan.

Over the past two decades, Taiwan's bamboo industry became weakened dramatically due to the broad application of bamboo substitute materials and the hiking labor, land, and other production costs. Annual bamboo-logging amount fell sharply from around 10 million units during the 1980s to current one million units only. It caused increasing idled bamboo forestland and shrinking labor force for the bamboo industry.

The price-slashing competition against counterparts from the Southeast Asia and China places Taiwan's bamboo suppliers and bamboo processors in an even worse situation. Furthermore, the 921 earthquake shattered bamboo's rhizomatous structure and scoured the soil in bamboo forestland. It seriously disturbs growth of bamboo and makes bamboo cultivation even more difficult. What's worse is Taiwan's entry into the World Trade Organization (WTO) in 2003, which lifted the ban on bamboo imports from China. The domino effect caused accordingly has almost overturned the entire bamboo industry in Taiwan. While bamboo farmers have transformed their farmland to cultivate other economic crops, Taiwan is now faced with an even worse problem of water and soil conservation for the forestland. It results in much higher social cost, shrinking green mountainous areas, and the fading bamboo culture.

In the future, Taiwan should restore bamboo forest and work out bamboo-logging management strategies for efficient development and application of the renewable material in Taiwan, under the missions for raising bamboo's value-added, strengthening green environment conservation, and raising industrial production. It will also create job opportunities for the weak groups of people and promote balanced development of urban cities and remote villages.

Full Application
Practical use of bamboo dates back to the Ying-shang Dynasty when bamboo was used for making arrows, bamboo slips, and various containers. In Chin Dynasty, Mong Tien invented the writing brush (shaft is made with bamboo's hollowed stem) which still see wide application today. Bamboo houses have been in a history of over two centuries. Today, bamboo construction material is still widely applied to various construction projects, especially often used for building scaffolds or shields at the working site. It's almost impossible to build temporary drama stages without bamboo which, compared to other construction materials, has the advantages of being strong, resilient, and easy to be processed. Meanwhile, bamboo branches and leaves are applicable for making brooms, bamboo hats, gabions, rafts, and bamboo bags. Besides, many daily necessities are made with bamboo-processed materials such as incense, knitting needles, bamboo mat, bird cages, barbeque stick, sushi stick, toothpick, bamboo curtain, bamboo sticks, bamboo shields, ceiling, and floor, among others.

The delicate basket is woven with willow-shaped bamboo.
The delicate basket is woven with willow-shaped bamboo.

Lately, the widening application of laminated bamboo to furniture industry and the newly-emerging niche of bamboo charcoal have considerably raised the economic significance of bamboo. Meanwhile, many artists are engaged in the art of bamboo weaving and bamboo carving. People have made “full application” of bamboo.

Cultural Significance
Bamboo is in an important position in Asian culture. Especially in Japan and Taiwan, people make intensive application of bamboo from daily necessities of baskets, plates, to houses, boats, and ritual items to be used at wedding or funeral ceremonies. In the eyes of literati and scholars, bamboo represents the virtue or spirit of integrity. Poet Su Dong-po once wrote, “People will look pale without meat in meal, and will appear smugly without bamboo in living place.” It well illustrates the close interaction between people and bamboo.

Bamboo also makes necessary items for customs rituals. In a Taoist fortune-praying ceremony for example, the black flag at the top of a giant bamboo stick in front of the ritual court is the sacred device to communicate with the God in the sky and the spirits underground. In the wedding ceremony of the Han people, the bridal limousine is tied with a two-ended bamboo stick which carries a piece of port meat to signify that the new couple will live together with good fortune throughout their lives. For the Paiwan Tribe, bamboo stick is used at primary rituals. During the Maljeveq (their most important God-worshipping ceremony held every five years), the tribal head and hunters will stab the “fortune balls” with bamboo sticks. For an engagement ceremony held in the tribal head's family, a bamboo hanging knife, gun, deerhorn, and Asplenium will be prepared to pray for harvest for the tribe and good descendants for the family. Rukai and Puyuma people also use bamboo for their wedding ceremony during which the new couple will swing on a high bamboo stand. It's the ritual for them to pursue happy marriage life. All these examples well illustrate a close relationship between bamboo and ethic groups of people.

Ecological Functions
Bamboo has several major ecological functions such as air-purifying, buzz-abating, shock-absorption, and environment embellishment. Experiment shows that the soil water of the watershed area inside well-developed bamboo forest is more active in penetrating vertically than diffusing horizontally. In other words, bamboo helps water penetrate into soil and prevent soil scour. It makes good shield to avoid breakdown or sliding of the forestland.

“Bamboo” grows in groups through spreading of its underground roots. The ungregarious bamboo has rhizomatous structure which is effective to prevent soil or water from flowing away. The caespitose bamboo, with hollow stems plugged (solid) at nodes and resilient in nature, can be used to resist strong wind and abate noise. Bamboo, in fact, is claimed to be the “New Green Energy” amid the global “energy-saving and carbon-reducing” movement. Bamboo grows to its full height in only one year and will become applicable within four years. The fast-growing characteristic makes bamboo an ideal alternative material for a broad range of application.

Bamboo forest is estimated to have a water conservation capacity of 10,000 MT (metric ton) water per acre and each unit of bamboo is able to maintain 6 cubic meter soil. Bamboo forest can absorb 12MT CO2 per acre annually and it generates 35% more oxygen than other plants. Meanwhile, bamboo forest provides shelter to many living creatures and is helpful to lower temperature around. Discarded bamboo becomes rotten and decomposed automatically, turning as nutrition inside soil. Bamboo is indeed a precious natural resource on Earth.

Conclusion
Bamboo is one of the most representative traditional consumer industries in Taiwan. Concerning the impact of the global economic recession and increasing pressure for environment protection, it's the priority task for Taiwan to transform and upgrade the bamboo industry as a means to strengthen international competitiveness and ensure continued industrial development. Compared to the information age of the 20th century, biotech will be the dominant industry for the 21st century. We should promote innovative bamboo processing business as one of the most eco-friendly industries based on the four management principles of “Nature, Ecology, Everlasting, and Organism.” That's for pursuing a healthier and eco-friendlier environment for the new age.