# Bamboo and Rattan/Bamboo/Course-1 Unit-11

## Bamboo use, Technologies and Enterprise Development

Course contributors: Dr Sas. Biswas and Dr SP Singh

## Block - 5 : Conservation and Management

Unit –11: Regeneration, Silviculture practices and Conservation strategies for selected species. It is well evident that bamboo finds multiple uses. In rural areas one can see houses are built by bamboos. Of course, in areas with very limited occurrence of bamboo houses are not so. For the want of bamboo and for variety of uses the resource has declined very rapidly. In fact, the methods of extraction being unscientific and unsustainable utilization of the resource are the prime cause of decline of resources. Pulp and paper industry, however small or large, is becoming very much dependent upon bamboo largely from its natural occurrence. Besides, its use in paper manufacture, bamboo finds its utility in basket making, panels, mats, water pipes, bridges, enforcement of concrete, handicrafts, even food in the form of fresh or preserved young shoots. Although most of the bamboos appear similar in shape and form occurring in different types of tropical forests – moist, dry deciduous and wet evergreen but they differ in growth and development under various physical factors of climate, soil and growth habits which need specific silvicultural practices for improvement. Each species of bamboo has specific silvicultural characteristics to provide important features for selection and improvement in quality planting stock.

## Climate

Most of the bamboos thrive at temperature which ranges from 8 degree C to 360 C. Reed like bamboos such as the species of Arundinaria grow up to 3500 m in mountains. In Latin America bamboo ascends to 3650 m above sea level. Some species such as Chusquea in Chile occurs in regions where frosts and snow are prevalent. From the rainfall point of view, minimum annual precipitation for bamboo is 1000 mm and maximum may touch 6300 mm ranging from the bioclimatic and agro-climatic zones to geographic regions. Relative humidity on an average ranges between 70-80 percent and quite suitable for the luxuriant growth of bamboo. It is found that a bamboo can grow under 75 mm and a maximum of 5000 mm of average annual rainfall. Some bamboos grow on all types of soil, provided there is good drainage.

## Soil

It is one of the most important locality factors for the growth and distribution of bamboos. Most of the species prefer growing on sandy loam to loamy clay soils. Sub soils with humus vary in colour from light red to yellow to bluish gray. Although bamboo grows well on swampy or wet stream beds but prefers well-drained soils. Dr. Biswas while working on the distribution of bamboos in northeastern region found that over 45 species of bamboos are found in mountain meadow and ferruginous soils. He found that forest soil with well decomposed and acidic nature (pH 4.5-6.5) and laterite deficient in potash and lime is suitable for the diversity of bamboo species. Different types of forest and soil have different kinds of bamboo. For example, betua bamboo (Bambusa polymorpha) suits to moist, fertile and well-drained soil; lathi or strictus bans grows in drier and open forest types; Madang or wootang bans (Schizostachyum pergracile) needs soil intermediate between the drier and moister sites; Jati or tulda bamboo grows fine in stream bed alluvium flats. Sandy or lateritic, stony hillside soils, rich moist soil such as alluvial stretches along streams. It is usually observed that the bamboos occurring in moist places grow luxuriantly and with better growth. The species in drier areas, although thin but hardy. Bamboos do not suit to water logged on heavy soils, such as pure clay or clay in mixture with lime. Well-drained localities with sandy loam or loamy soil are best for the growth of bamboo.

# Forest types=

It is now evident that the physical geography coupled with precipitation out of rains and moist conditions, temperature and altitude result into types of forests with rich diversity of bamboo. As told earlier tropical forests have larger diversity of bamboos in species and forms. Temperate forests have reed like bamboos, whereas alpine type have reed like and smaller varieties of species. In northeastern states wherever these is practice of shifting cultivation (jhuming) the spots in the country sides are studded with bamboo brakes. Such areas traversed by jhuming north eastern India is often found with large uniform growth of muli (Melocanna) bans, kako (Dendrocalamus hamiltonii), dolu (Schizostachyum dullooa) species of bamboo. One can see that those areas which are open in forest due to the removal or felling of tree growth bamboo becomes quite spread. It forms understorey of the deciduous and dry forests, evergreen and semi-evergreen in tropical areas. It is often found that the understorey is mostly composed of single species of bamboo. In the forests of oak, deodar, spruce and silver fir in the Himalayas, broadly speaking, the species of Arundinaria (presently split into various genera) is quite frequent. In semi-evergreen to mixed deciduous forests of Cachar hills in Assam and in Andamans you can find large climbing species of bamboo (Dinochloa andamancia, Melocalamus compactiflorus). In lower elevations in hotter areas one can see bamboos growing in association with broad-leaved trees and shrubs.

## Silviculture

Silviculture of bamboo means as how to improve the stock through certain cultural operations. This may include the identification for the salient features of a particular clump for better growth and production. In order to have better features in every aspect, choice of the variety depends right from its natural occurrence to its artificial propagation. Various factors such as rainfall, temperature, humidity, aspects of occurrence association of species, morphology, flowering and fruiting (phenology) play important role in this aspects. Behaviour of bamboos in terms of its colonizing nature is very important, sometimes you may plan to afforest some area with the freshly collected seeds of some bamboo, and when grown and in times to come the plant becomes invasive and subjected to a heavy task of eradication. It has been observed that following flowering and seeding, whole plant die but the bamboo regenerate from seedlings. In case of non clumping variety occupation of the open area is faster through the new culms sprouting from under-ground rhizomes. Sometimes disturbances such as slash and burning or extensive cutting of culms help in the profuse regeneration by giving rise to new culms from the rhizomes under the ground.

## Volume and yield

Culms per clump per unit area are the main components of the production of bamboo from natural stands. The dry culms from the planted stock are the saleable produce. It is observed that there may be 3-9000 culms per hectare. Based upon three year rotation this may touch upon 15,000 per hectare. Muli bamboo weighs 4.4 tons (4.5 m tons) per 1000 green culms. The air dry culms weigh 2.5 tons (2.6 m tons). Madang and betua bamboos of northeast India used for paper production weigh from 4.2 to 4.7 metric tons. Muli bamboo culms yield 21 metric tons per hectare, large variety of kanta bans gives 2.5-36 metric tons per hectare. Depending upon the locality facators such as moisture, temperature and soil the production of culm shoots may vary and so in the volume and yield. Following table shows certain characters of bamboo for silviculture studies.

Species/Vernacular name Height (m) Internode (cm) Diameter (cm) Wall thicken (cm) Culm sheath (cm) Characters Arundinaria falcata (Ringal, Ningal) 2-4.5 10-20 1-2 Thin 15-30 x 3-7 Clumping Bambusa balcooa (Bhaluka) 16-25 20-45 8-15 Thick 15-45 x 15-40 Densely clumping with stiff branching Bambusa bambos (Kanta bans) 26-30 30-45 15-18 Cavity 1/3 of culm 29-38 x 22-31 Very densely thorny and congested clump Bambusa tulda (Jati) 6-10 30-60 5-10 0.7-1.30 15-23 x 15-26 Clumping but sparsely growth on removal Dendrocalamus hamiltonii (Kako, pecha) 18-27 30-50 10-13 0.7-1.3 30-45 x 16-20 Densely clumped Dendrocalamus longispathus (Rupai) 17-20 43-75 7-13 0.7-1 30-50 x 10-20 Tufted and diffuse as well Dendrocalamus strictus (Lathi bans) 5-17 30-46 2-8 Thick Varying 8-30 cm long Deciduous densely tufted Melocanna baccifera (Muli bans) 12-25 23-56 2-8 Thin 12-18 cm long Singly at 1-2 m intervals Schizostachyum dullooa (Dolu) 8-25 40-100 5-10 Thin 12-30 x 10-25 Open clumps

## Conservation and Management

Bamboo has several environmental benefits. The interwoven architectural design of its root system helps in soil stabilization, checks erosion and landslips, averts flood and protect riverbanks. In times of natural disasters such as earthquakes, cyclones and floods replacement of housing materials made of bamboo is cheaper and convenient for the rural poor being renewable natural resource than the concrete structure. Besides the roles of bamboo in soil rehabilitation, it has great role in the fixing of carton dioxide (carbon sequestration). Better planting techniques and after care of naturally and artificially regenerated stock of bamboo are the main features of effective conservation and management. Conservation of bamboo depends upon as how you gather knowledge on different aspects of biology, distribution, growth and development, and its protection from different threats. The main threats to bamboo are fire, browsing of seedlings by cattle, including goats, and seeds being eaten away by animals and birds such as rats, hares, squirrels, jungle fowls, deer, monkeys, parrots etc. The damage by man is much higher in terms of the degradation and decline of bamboo cover.

## Regeneration and Threats

Regeneration of bamboo is possible by natural artificial means. Natural regeneration depends much upon the nature as how bamboo grows, its flowering cycle whether gregarious, sporadic or annual. What types of soil and climate it prefers to grow in nature. We often see large areas under bamboo forests. Do you know that most of such bamboos come up from the mass seeding as a result of large-scale flowering? Seeds fall off and the clumps and culm having died after the flowering cover the seeds to protect these from animals and birds as far as possible. This is the time when the dried and dead mass of bamboo becomes inflammable particularly in hot season and at this period accidental fires may take a heavy tall if you do not harvest or protect the crop well in time. At the on set of rains or some moistly conditions the grass like seedlings appear as green carpet in the areas where bamboo has seeded in mass.

Young seedlings do not prefer heavy shade. The heavy growth of weeds suppresses the growth of the seedlings. Light shade is helpful to provide them protection against frost and drought. It takes up to 10 years for the seedlings to occupy the areas left open by the flowered bamboos. Some attention during this period can help in providing clump to clump space management. There is need to observe and enforce measures on indiscriminate cutting and removal of culms and young shoots, and grazing. The growing clumps need proper distance among them, otherwise there is congestion, which deteriorates the quality of bamboos and reduces the yield. Sometimes due to natural damage by wind and animals bamboo culms fall on the ground and give rise to new plant by rooting at nodes.

## Artificial Regeneration

There are following methods to regenerate bamboos artificially. (i) Direct sowing of seeds (ii) Nursery raising of seedlings and transplanting. (iii) Planting separated rhizomes (macro proliferations) (iv) Propagation through cuttings. (a) Rhizome cuttings (b) Offsets (c) Stem cuttings (culm) (v) By layering.

## Direct sowing of seeds

Usually seeds of bamboo germinate within 5-10 days with good percentage when sown in polythene bags directly than in beds. The viability, that is, dormancy of bamboo seed remains between 1-2 months but under controlled storage conditions which can be increased. It is found that if the seeds are stored in a tight container over silica gel they remain viable for 1-3 years, sometimes over a longer period. There is advantage of the seed-raised planting materials for the convenience in transportation and large-scale plantations. It is estimated that on an average a clump of Kanta bans produces 100 kg of seeds. A hectare may contain about 100 clumps of such variety of bamboo.

## Nursery – raised seedlings and transplanting

Transplanting of seedlings from nurseries near the planting sites becomes necessary in the event of uneven germination, slow growth of resultant plants and exposure to animal damage etc. 1-2 month old transplants measure about 15-45 cm height; those of year old are between 90-120 cm and 2 years old about 150-240 cm depending upon growth conditions. For the effective management there is need to control the weeds.

## Planting of separated rhizomes and Macroproliferation

Separation of culms with portion of rhizome intact provides suitable material for planting purpose. This is owing to the fact that the reserve material stored in the rhizome is used in shooting and enhancing the growth. There is growing demand for more and more transplantable planting materials. To meet this demand in shortest possible time certain techniques (macroproliferation) have been developed by the institute such as Forest Research Institute (FRI), Dehra Dun. You can see this is very simple and it is in fact through the better understanding of the growth of saplings from seeds. If you see a bamboo seedlings of 30-40 days old raised in a polythene bag or root trainer, there is growth of leafy shoot which are called ‘tillers’ similar to that of wheat seedlings. These tillers ultimately transform into new culms with development of rhizomes. After 9 months bamboo seedling attains 4-5 miniature culm stage. At this stage each seedling may be separated into as many units with independent shoots, roots and rhizomes. At this time these are required to be kept under shade and watered at least two times in a day for three days and after that under the sun. In this way each seedling could be multiplied several times. The repetition once every six months and over the years would result in increasing the numbers of propagules (growing materials). In absence of the availability of good quantity of bamboo seed this method of multiplication is most desired one. A flow diagram is provided to explain this technique and the management of raised saplings for field planting.

## Rhizome cuttings and Offset Planting

Rhizome cuttings and Offset Planting Rhizomes found in elongated form particularly in the species of temperate or colder regions (non clumping and monopodial) are cut into desired length and planted. If you remove a rhizome which is a underground portion below a culm or clump, you can see some vegetative buds typical of what you can see in a sprouting ginger (Adrak). The buds in a bamboo is quite active in growth season. In clumping variety it is found that the commonest method is through offset planting. It is quite suitable just before 1-2 months before monsoon season, when the rhizome buds are most active. For the development of small groves of bamboo, it is quite favourable. From the conservation point of view some of the clumps of bamboos when found as uprooted and eroded, cutting of clumps with enough number of buds provide materials for propagation and protective measures.

Stem or Culm cuttings Stem or culm cuttings is generally done with 1-2 noded cuttings of 1-3 years old culms. The cuttings from the basal portion are most successful. You can see that this is typically what we see in the planting methods of sugar cane with 1-3 nodes bearing buds at the joints, similarly the bamboos are grown. Besides horizontal, the cuttings may be placed obliquely as well. Month of April is suitable for planting. The rooting hormones and other chemicals such as IAA (Indole acetic acid), IBA (Indole butyric acid), CBA (Coumarin Boric Acid), NAA (Naphthalene acetic acid) are suitable for successful rooting.

Layering Layering is mostly done by burying lengthwise the whole culm of 1-2 years old by the onset of rains. Nodes sprout the young shoots which can be separated and grown. Such practice is quite prevalent in north eastern region of the country.

## Rhizome cuttings and Offset Planting

Rhizome cuttings and Offset Planting Rhizomes found in elongated form particularly in the species of temperate or colder regions (non clumping and monopodial) are cut into desired length and planted. If you remove a rhizome which is a underground portion below a culm or clump, you can see some vegetative buds typical of what you can see in a sprouting ginger (Adrak). The buds in a bamboo is quite active in growth season. In clumping variety it is found that the commonest method is through offset planting. It is quite suitable just before 1-2 months before monsoon season, when the rhizome buds are most active. For the development of small groves of bamboo, it is quite favourable. From the conservation point of view some of the clumps of bamboos when found as uprooted and eroded, cutting of clumps with enough number of buds provide materials for propagation and protective measures. Stem or Culm cuttings Stem or culm cuttings is generally done with 1-2 noded cuttings of 1-3 years old culms. The cuttings from the basal portion are most successful. You can see that this is typically what we see in the planting methods of sugar cane with 1-3 nodes bearing buds at the joints, similarly the bamboos are grown. Besides horizontal, the cuttings may be placed obliquely as well. Month of April is suitable for planting. The rooting hormones and other chemicals such as IAA (Indole acetic acid), IBA (Indole butyric acid), CBA (Coumarin Boric Acid), NAA (Naphthalene acetic acid) are suitable for successful rooting.

Layering Layering is mostly done by burying lengthwise the whole culm of 1-2 years old by the onset of rains. Nodes sprout the young shoots which can be separated and grown. Such practice is quite prevalent in north eastern region of the country.

## Integrated approach for the bamboo management

Diseases and Pest


Management of bamboo through integrated approach is quite important. Diseases and pest of bamboos deteriorate the bamboo resource and variability for the quality planting materials. Root rot, culms-rot, witches broom, blights seed borne fungi etc. cause damage to bamboo resource. Do you know that there are over 40 species of insect pests which attack bamboo? The defoliators, shoot and culm borers, sap suckers cause considerable damage.

Control measures Various control measures on disease and pests through mechanical, pathological and silvicultural aspects can help in successful management of bamboo resource. You can see around that the bamboos under plantation are easier to be managed than in the wild. The clumping (caespitose) varieties need intensive management. In general the following factors are important to manage sustainably the bamboo forest, both in production and natural areas. These are: i. Felling cycle ii. Intensity of felling iii. Method of felling The age or longevity of bamboo culm and the growth pattern among the bamboos vary with species, localities and climate, and accordingly the period of felling cycle is fixed. Felling method, intensity and cycle aim at sustainable management and timely utilization of bamboo. From the conservation and the sustainable management point of view, the harvesting of bamboo is advised from sixth year with the extraction of 6, 7, 8 and 9 culms per clump per year. The culms of 1-2 year should be left for regeneration. Besides, maintaining the stock in nature, the uncommon and promising species and their variability should be introduced in bamboo garden (Bambusetum). One can visit such Bambusetum in different parts of the country, one at FRI Dehra Dun provides a delightful learning about the growth and development of bamboos introduced during the past over seven decades.