Bamboo
The golden Species
With more than 111 genera and 1575 species in the world, bamboos form a large group of arborescent monocots, distributed in tropical and subtropical forests. The height of bamboo species ranges from less than a meter to as tall as 30m. There are three growth forms among bamboos viz., herbaceous, climbers and woody (arboroscent). Some of the woody bamboo species are the fastest growing plants reaching their full height in two to four months. During growing season, some species (Eg. Phyllostachys bambusoides) grow even upto 1.2m a day. Due to their fibrous root system, bamboos prevent soil erosion and create effective watersheds by binding soil along fragile riverbanks, deforested areas and in places prone to landslides. It is an important species for landscaping as bamboo provides shade and acts as a windbreak. There are about 1500 traditional uses of bamboo broadly classified into household, industry, weapons, energy, transportation, fisheries, agriculture, medicine and construction.
In a remarkably short span of two decades bamboo sector in East and Southeast Asian countries have developed in an unprecedented manner. China has emerged as the leader having an annual growth rate of 30% and currently stands at about US $ 3 billion. The major reasons for the rapid progress is the identification of bamboo as a raw material for pulp, paper and rayon, laminated bamboo, parquet flooring, ply bamboo, bamboo composites and bamboo charcoal coupled with the mechanization of the traditional sectors like bamboo shoots for food, chopsticks, toothpicks and bamboo handicrafts.
With regard to bamboo resources and diversity, India is only second to China and, hence, the potential for development of bamboo sector in India is very high. During the world environment day 1999, an integrated program for the development of the bamboo sector was launched by the Indian Prime Minister. As an initiative of the Technology, Information, Forecasting and Assessment Council (TIFAC), and Department of Science and Technology with the support of Planning Commission, a National Mission on bamboo applications was set up to provide new impetus and direction to the sector and to enable the realization of its considerable potential. As a result of this rediscovery of the potential of bamboo attempts to develop bamboo sector in a holistic manner starting from organized cultivation to product innovation and marketing has been initiated by various agencies. In Kerala, the State Planning Board has initiated a comprehensive scheme for the development of bamboo sector in the state.
The first step required for the development of bamboo sector is the bamboo resource development. Without accessibility and availability of raw material, any industry is likely to be short-lived. Presently, except in North-eastern states, most of the bamboo comes from forest areas and the statistics show that the quantity available is not sufficient to meet the requirement. In addition, gap in supply may also increase due to relaxations in forest laws for conservation of natural resources and gregarious flowering. It will be appropriate to initiate cultivation of bamboo in non-forest areas and wastelands in the country. Also the productivity of existing bamboo areas can be enhanced by scientific management and harvesting.
Morphology and Flowering of bamboo
Bamboo plant, belonging to the monocots, consists of roots, rhizome, culms, branches, flowers and fruits. Bamboo roots are fibrous and form a dense network in the soil. Roots grow to a depth of less than 50cm from the soil surface but the lateral spread is more and may be even up to a diameter of 8m (Bambusa bambos). Rhizomes, the underground stem supports the aerial parts of the bamboo clump. Based on the branching patterns, basically two types of rhizomes have been reported – sympodial (pachymorph) and monopodial (leptomorph) which also governs the type of growth form of the bamboo. The sympodial type of bamboo forms clumps (grows as a cluster in one spot) where as the monopoidal species produce runners (walking bamboo). Culm is the technical term for bamboo stem and in woody bamboo they are large in size. Each culm consists of nodes, internodes, axially buds and leaves. In some of the basal nodes, root primordial are also present. Mature culms are the result of a process of primary growth through which culm reaches the maximum diameter, elongation of internode in a telescopic fashion and subsequent hardening through lignification. The node is from where a branch is produced on the stem. Internodes (the culm parts between successive nodes) may be solid as in Dendrocalamus strictus, or hollow as in Bambusa bambos and the length of internodes varies in different species. Although three types of flowering (annual or continuous flowering, gregarious or periodic flowering; sporadic or irregular flowering) have been reported among bamboos, most of the woody bamboos that are commercially useful belong to the gregarious group. The growth and flowering pattern are peculiar in woody bamboos. Vegetative growth by formation of shoots every year takes place for decades and at the end of a definite period, flowering starts synchronously in all the clumps that originated from a parent clump (by seed or through or vegetative methods of propagation), even if they are geographically separated. The vegetative phase (known either as flowering cycle, intermast period, physiologic cycle, etc) varies from three years to as long as 120 years in gregarious flowering species. Vegetative growth stops with the onset of flowering. When flowering occurs, it lasts for about 2-3 years in the same clump based on the species and locality. The bamboo culms dry up after flowering with or without seed set. However a few exceptions are also observed as in some of the clumps of Dendrocalamus giganteuus in which vegetative growth continues after flowering without formation of viable seeds. From the seedlings it takes about 5 to 7 years for the bamboo to reach maturity before the culms could be harvested commercially.
Cultivation of Bamboos
The diversity of species and capacity for adaptation makes bamboo suitable for growing in different sites. Natural distribution is mainly dependent on rainfall, temperature and soil type. The topography, however, does not play a serious role in bamboo growth. Different species of bamboos grow in areas, which receive an annual rainfall of 1200 to 4000 mm and where mean annual temperature ranges from 8 to 360C. Bamboos grow well in different types of soils.
Species suitable for cultivation
Although about 18 genera and 134 species of bamboos are reported from India, only less than 20 species are commercially important. Others are rare or restricted in occurrence. The species that can be cultivated in large-scale are given below.
- Bambusa affinis Munro
- Bambusa balcooa Roxb
- Bambusa bambos Voss
- Bambusa nutans Wall.ex.Munro
- Bambusa pallida Munro
- Bambusa polymorpha Munro
- Bambusa tulda Roxb.
- Bambusa Wamin Camus
- Bambusa vulgaris Schrad.ex.Wendl
- Dendrocalamus asper
- Dendrocalamus brandisii (Munro) Kurz.
- Dendrocalamus gigantes Munro
- Dendrocalamus hamiltonii Nees
- Dendrocalamus longispathus Kurz
- Dendrocalamus membranaceus Munro
- Dendrocalamus strictus (Roxb.) Nees
- Melocanna baccifera (Roxb.) Kurz.
- Ochlandra travancoria Benth.
- Pseuoxytenanthera stocksii
- Schizostachyum pergracile (Munro)
- Thrsostachys oliveri Gamble
Source : Nursery & Silvicultural Techniques for Bamboos, Kerala Forest Research Institute.