By: Krishnakumar, V.G
Bamboos are big grasses coming under family Poaceae. It is a tall grass with hollow stem. Bamboos are a group of grass having a large number of varieties and hence grouped as Bambusoideae. Bamboos are found everywhere, from seashore to icy mountains. These plants are mainly found in Asia. Out of the 1500 species, half of these species are found in the Asian region. In India, 146 species are identified. Bamboos are found as wild growth in forest areas and also cultivated in homesteads for domestic purposes and industrial purposes. Bamboo is also known as poor man’s timber, green gold etc. In the pre historian periods, split bamboo was used for surgery especially for removing umbilical cord. It was used for coffin too. In short, bamboo was used from cradle to coffin. September 17th is celebrated as World Bamboo Day.
The Bamboo Plant
This grass has got a strong rhizome growing under the soil. It germinates from a tiny seed and looks like a tiny grass having a height of 5-7 cms. After gaining healthy growth, the underground stem, rhizome develops. New pair of shoots sprout from the rhizome which will have more height than the first one and the process goes on till big ones having the optimum height of that species develop. In most of the species, it will take a time span of 4 – 5 years for such big bamboos to develop. With the age of the plant, the rhizome also expands and big bamboos are generally found on the periphery of the rhizome. Smallest bamboo is Raddiella vanessiae having a height of 2 cms found in French Guyana and the largest bamboo is Dendrocalamus giganteus, (giant bamboo) originated from Myanmar having a normal height of 40 metres. The life span of bamboos vary from 35 years (almost all species) to 150 years (yellow bamboo- Bambusa vulgaris). All the bamboo species are considered to be fast growing. Since these are monocots, adventitious root system anchors the plant to earth.
Each bamboo is termed as a culm and the group is termed clum.
Many of us grow lucky bamboo in our drawing room. Actually, the lucky bamboo Dracaena sanderiana is not true bamboo.
Flowering of Bamboos
Almost all species of bamboo flower once in a life time. That denotes the end of the clum’s life. The seeds of big sized bamboos ( Bambusa bamboos[katha bans], Dendrocalamus giganteus [mota bans] etc) will be very small like that of a paddy grain, while seeds of small sized bamboos ( Melacona baccifera [muli bans], Ochlandra travancorica [reeds] will be big like that of an arecanut. There are two types of flowering in bamboos, sporadic flowering when stray incidents of flowering occur in the area and gregarious flowering is the phenomenon when the entire population of that bamboo species flower. It can be noticed when the production of new shoots are stopped in the clum for 2 consecutive years.
Propagation of Bamboos
Bamboos are propagated through various means. Mainly the propagation is done through conventional method of germinating seeds. But there are various constraints for propagation through seeds as the bamboo plant flowers after 30-40 years. After the seedfall, the clum dies off. The seeds have a viability period of 3-6 months, if stored in normal conditions. It is a fact that the bamboo seed is highly nutritious and rodents are attracted when seed fall begin. Thus a sizeable quantity of seeds would be lost through rodents and wash off through rains. Hence, various vegetative propagation methods like layering, tissue culture etc. are used for propagating bamboos. Layering is a simple practice of covering the node with soil to induce root formation. After 30 days, when sufficient roots and new shoots are developed, that node can be severed without damaging the roots and shoots to plant.
Tissue culture method is a costly production procedure and is used only when production is needed in large quantities. In Assam, one such Tissue Culture laboratory is functioning under Hindustan Paper Corporation Ltd (Nagaon Paper Mill, Kagaj Nagar, Jagi road, Morigaon district). That laboratory was installed to meet the heavy demand of northeast after the gregarious flowering phenomenon in that area.
It is an interesting phenomenon that when the mother bamboo clum flowers, all of its offshootted plants wherever planted in the world will flower.
Maintenance of Bamboo Clum
Bamboo can be cultivated for domestic and industrial needs. Hence, species need be selected before planting. Fallow lands can be effectively utilized by planting bamboos. It can be planted at an escapement (distance between each plant) of 5 metres. Thus in one hectare, 400 seedlings can be planted. Planting has to be done during monsoons in 30cm3 pit. Periodical weeding and protection from grazing will promote healthy growth. Manuring, if done, will boost the growth. Chemical fertilizers with silicate is ideal for bamboos. New shoots generally form during the onset of monsoons. Long culms will form from 4th year of planting. It will take minimum 2 years to get ready for commercial exploitation. 5-6 mature culms can be extracted from every clum. 36 numbers of full length bamboo will weigh 1 MT. While extracting bamboos, only mature bamboos alone need be felled and no clear felling of the clum is advised for the health of the clum and sustained yield. Thus the farmer can extract a minimum quantity of 40 MT from one hectare of plantation every year from 6th year onwards for a period of 30 years. It may be noted that after 3rd year, no special care is needed for these plants till flowering.
Eco- Friendliness of Bamboos
Every bamboo clum (after 6th year) releases double the quantity of oxygen than that of a tree having the same age. Since the roots are very much binding to soil, it can be planted along the riverbanks to prevent soil erosion, as is being done in Kerala and other states. Properly treated bamboos can be used for building and other constructions. Tender shoots of bamboo is edible and is of much demand in North east.
Bamboo is the green gold serving the man in all walks of life. National Bamboo Mission is promoting the cultivation of bamboos all over the nation through concerned State Bamboo Mission.