Bamboo and Rattan/Rattan/Course-1 Unit-11a
|Work in progress, expect frequent changes. Help and feedback is welcome. See discussion page.|
- 1 Conservation and management, ecological aspects
- 2 Assignment
- 3 220.127.116.11. In situ and ex situ conservation
- 4 Assignment
Conservation and management, ecological aspects
You have earlier read about how many of the canes species in India are facing various degrees of threat and there is danger of their extinction. These are placed in the endangered category. Conscious and conscientious efforts are needed to prevent these species from disappearing i.e there is need to conserve these species. To appreciate why canes are under threat we would need understand how man has been utilizing cane over the years – suddenly why this talk of conservation while can has been utilized for so long over the years. The following section attempts to look into these aspects and to identify methods to improve the current situation.
To understand why canes are under threat, we need to look at three things:
- Canes (and derived products) as a forest produce
- Their utilization by humans
- The implications of human activities on them and their habitat.
All three suggest the same thing AND only one is described below. If you want the three bullets then even later you will need to write about each distinctly!!!
11.2 Why cane is under threat?
Cane is an important forest produce that is used for diverse purposes. Cane and bamboo are the most important non-timber forest produce in our country. Out of the three main centres of cane distribution in our country viz., Western Ghats in South India, Andaman and Nicobar Islands and North East India, it is only from North East India that canes are liberally extracted. The canes from this region are supplied to factories located all over the country. This paved the way for enhanced demand and exploitation from the wild though the unscientific ways of exploitation has led to depletion of resources and imbalance in cane population in the regions.
11.2.1 Overexploitation of cane
Due to over-exploitation for commercial purposes along with the drastic depletion in cane habitats, cane resources and raw material became scarce. This forced the governments to restrict cane extraction in south India and Andamans. Naturally the pressure increased on the northeastern region leading to rapid depletion of quality raw materials. The habitat destruction and changes in land use compounded this problem. It is clearly evident that canes are by and large habitat specific and natural regeneration is extremely slow and inefficient. Regeneration is also affected due to difficulties associated with seed germination and reduced availability and short viability of seeds.
Canes are utilised for domestic and traditional purposes, as well as for trade and commerce. However the major demand is from their use in the furniture industry, though handicraft industry also uses cane for various products. Besides, the local people in North-East parts of India eat the young shoots of cane. They also eat fruits of certain species like Calamus flagellum, C. erectus, C. khasianus, C. leptospadix, etc.
The long thin canes are employed as rope and cordage for binding purposes while large diameter canes are split and utilized. In the North East canes are employed in the construction of suspension bridges, bamboo houses, etc. The leaves of Calamus flagellum, Calamus erectus and Zalacca secunda are used for roofing. Canes are also used by local people in making different agricultural implements, articles and traps used in hunting and fishing. They also find place in festivals and rituals of different tribes, particularly in the North East.
All the species of cane are very specific in their microclimatic requirements apart from other factors like high humidity, good drainage, closed canopy cover over their head and supporting trees for climbing. The population of cane in any area reacts very sharply to any alteration in their habitat. Due to all these natural limitations their regeneration rate is also quite slow in comparison to other forest trees. It takes 10-15 years to attain maturity for most of the species. As a whole, the rate of natural regeneration has not been able to cope with the demand, which has resulted in the depletion of the population from nature. If appropriate conservation measure are not adopted many of the important species may vanish from the region. This is particularly important in the case of some of our rare and endemic species (see 11.2.2).
11.2.2 Reduction in forest cover and destruction of habitat
Some of the new species described recently also fall into the rare category with limited distribution and low population. There are several occasions when field observations over a period have shown that there was a marked decline in forests as a whole and cane species in particular, in many places in our country.
Majority of canes prefer a sylvan habitat – that is they prefer to grow in the forest. Shifting cultivation, logging, developmental activities and urbanization are contributing to make the areas inhospitable to cane growth by destroying their preferred habitat. The problem of poor natural regeneration is compounded due to non availability of seeds for regeneration as many canes are cut before they form fruits and seeds. A recent trend seen is the collection of fruits for decorative purposes, thus leaving nearly nothing for regeneration in case of some selected species like Calamus erectus. As mentioned earlier fruits of certain species are edible and people tend to collect them for this purpose adversely affecting the regeneration in the natural way.
11.2.3 Reduction in seed and fruit dispersal
Cane fruits are dispersed through birds and animals in nature. A very disturbing fact is that due to deforestation and decimation of forests the number of birds and animals have drastically reduced; they do not visit the degraded areas thus affecting dispersal and regeneration of canes.
Rattans are seldom planted by forest departments in their plantation programme. There is not much effort in this respect in recent past and many of the newly created plantations are failures due to different reasons. Private individuals or companies are reluctant to grow them as they take a long time to establish and because they are profusely thorny they are not very suitable for homesteads. Quite often the reason for not planting cane is non-availability of quality seedlings. At present there are no commercial nurseries selling cane seedlings despite their potential for being in great demand as young plants for growing in pots as indoor plants.
The current status is alarming for this valuable resource. An integrated and continuous conservation effort alone can save cane resources for future.
11.2.4. Endemic species
Species are defined as endemic if their distribution is restricted to a particular area – it is not found in other areas. Conserving these species becomes all the more important since if these are lost they can never be recovered. A list of endemic species is given in the table below From the table it is fairly clear that endemism is very high in Canes compared to any other group of plants. This is because of their narrow habitat preferences and their dependence on external agencies for fruit and seed dispersal. It is important to understand that the endemic species are under greater threat. Though many of these canes are not of immediate commercial importance they also need to be conserved – they serve as genepools that are valuable to impart the desired variation in the gene pool. Many of them may find a valuable role in future as genetic resource – they may have characteristics that you may need to introduce in your cultivated species. Hence it is very essential to ensure even their conservation.
Some Endemics canes: ( endemics are those that have restricted distribution to a particular locality) (we need tto put a table here)
Check Your Progress Exercise 1
From the above discussion it is obvious that efforts need to be made to conserve cane species, but any such effort needs to be preceded by identification of the species under threat. Only then can we proceed to find ways and means rehabilitate and regenerate them. The following table gives a list of species that are perceived to be under threat. It is not as if only these species demand our attention – unless scientific management and sustainable harvesting practices are evolved and adopted, all species of rattans are going to be on the endangered lists very soon. What is discussed in the table is only an attempt to prioritize species for immediate conservation strategies.
Table showing Rare, Endangered and Threatened species of rattans. Are we using these terms interchangeably?? We have not differentiated in the table!!!''
11.3.1 How to conserve?
This is the next question that needs to be answered. Towards this end we need to explore what we can do or should do. Firstly we need to understand the distribution of the endangered species that need to be conserved. Thus survey and documentation is paramount. This will help us know where is it growing, how big is the population, the current level of regeneration, the species that tend to grow together (associated species) - in affect all characteristics that tell us more about the endangered so that we can work towards increasing their numbers and conserving them.
18.104.22.168. In situ and ex situ conservation
Conservation is carried in two ways – in situ and ex situ. In in situ conservation the number of plants of any species are increased in their original place of occurrence or habitat. As against this, in ex situ conservation attempts are made to grow the plants at other places other that their natural place of occurrence. For this, their habitat requirement need to be studied so that it can be simulated in ex situ conservation efforts, which helps in growing them outside their natural area of occurrence. Protection measures are to be offered to such plants and their habitat so that adverse factors acting on them could be minimized.
7.3.2 Commercial farming
We can also help in regenerating threatened species using artificial regeneration methods by augmenting the required facilities and conditions. Modern methods of nursery raising and tissue culture can help raise more seedlings of the required species and help raise plantations in ideal locations. Botanical gardens and research institutes can help recovery of the endangered and threatened species by growing them in these plots and offering protection. Perhaps this can ensure their continued survival in the world for future generation and research.
A very important attempt would be promoting the commercial plantation and farming – we need to attract adequate attention so that more people are interested in their cultivation.
Above all, awareness on the relevance and importance of conservation of our endangered resource need to be created among all stakeholders. One of the leading biologist Dr. CTS Nair from FAO compared canes conservation to Tiger conservation. As in Tiger conservation though tiger is targeted to be conserved being at the top of the pyramid, the entire flora and fauna too get the benefit of conservation as it is difficult to succeed in our efforts caring only for the targeted animal. Similarly canes are highly habitat specific and for survival of canes it is essential to get the habitat conserved and developed to a level where these plants can thrive.
Naturally occurring areas of cane concentration may have to be identified and delineated as conservation centres like the sanctuary or reserved forest so that adequate legal protection is offered to this group of plants. Each one of us can help in the conservation be adopting someof these efforts.
7.3.3 Some efforts at Conservation of Rattan
The first attempt for a planned scientific study of rattans in India was started by Dr. Renuka(complete name?) at Kerala Forest Research Institute. She has not only studied the taxonomy of Indian canes but also collected important species and raised a cane garden - canetum at KFRI, Trichur, Kerala. This is a pioneering effort and has contributed immensely for conservation of this group.
Dr. Basu?? from Botanical Survey of India has brought out a compendium of Indian canes which is very useful for conservation research. Dr. Haridasan and his team have raised a canetum of northeast Indian canes in SFRI Expand all abbreviations Itanagar at Chessa which is the first attempt in the region. There are nurseries of canes in SFRI Itanagar and RFRI, Jorhat, KFRI Trichur etc. recently many of these organizations has helped different agencies for taking up plantation of canes under forest department sponsored projects. There is a need to increase the scope of such works and establish more plantations in both government and non government sector. Simultaneously scientific methods of extraction and sustainable harvesting need to be adopted. Indian canes are losing their value for want of adequate treatment. There is an urgent need of providing treatment facilities on site for value addition and better quality. Dr. Damodaran and his group in KFRI has devised easy tools for this purpose. Training is essential component for treating canes to desired levels. (remove???) Thus adoption of adequate technology for conservation can take our cane sector much forward ensuring the ecology and continued survival of species.
11.3.4 Regeneration :
Rattans generally bear fruits during the rainy season, but the exact time differs from species to species. The duration the fruits take to mature also differs from species to species. There are many reasons, which inhibit the natural regeneration of canes in the forests. As the fruits of rattans have a fleshy cover that is tasty, the fruits are eaten by human beings, squirrels and birds. The mature seeds, which fall directly to the ground, generally take between 60-70 days for germination. The sloppy (Haridasan – pl use a different word) habitat and rainwater help in dispersal to some extent. The growth rate of the young plants is very less. In forests mature plants grow by 1-3 m per year.
In our country there are a few species, which multiply by stolons, for example C. flagellum. Plantlets develop from each internode and as they strike the ground, they grow into independent plants. The degree of regeneration of rattans in the forest varies from species to species.
All (most?? see last sentence of para) species of rattans are colonizing in nature and the species like C. leptospadix, C. flagellum, C. gracilis, D. jenkinsianus, P. assamica bear abundant fruits. They occupy any open areas, cover the gaps, and establish themselves. The regeneration of species like C. erectus, C. inermis, C. nambariensis, C. khasianus, P. bractealis are poor.
The destruction of cane bearing areas is another reason for cane habitat shrinkage. Due to the demand, even immature canes are also extracted and this drastically affects the number of mature plants in the forests. Moreover, canes are dioecious (male and female flowers are borne on separate plants) i.e. only half the populations tend to be female plants (that produce seeds). The natural calamities like forest fires have a direct impact on the regeneration of canes in its natural habitat.
Due to damage of forest cover, the host trees required for climbing of canes are wanting in many cases, and hence the growth of canes also gets disturbed or damaged due to lack of support plants. This is the eventuality in many of the forests.
Moreover, there is gross inadequacy in the scientific management of rattans in our forests. The harvesting rules have not been standardised nor the working plans prescribed. This results in indiscriminate exploitation and consequent depletion in their availability. This further affects the availability of seeds for regeneration and survival of species. Formation of axillary shoot development as well as root development from the distal nodes have been reported from some south Indian species such as C. hookerianus and C. gambleii. Possibilities of such development in other species could be explored to augment regeneration.
Another method of natural regeneration is by means of rhizomes, produced by the side of the original culm, as seen in C. floribundus. By and large artificial regeneration is through seeds, rhizomes or by stolons. Tissue culture experiments are in its initial stages and no visible impact has yet been seen.
As mentioned earlier canes are more habitat-specific and their distribution in India show characteristic features of concentration. This is perhaps due to the prevalent forest type in those areas, by and large the preference is for moist tropical or wet tropical forests.
Canes are generally prickly climbing palms that need support of forest trees to climb. These plants have adapted for such life by developing certain climbing appendages like flagellum, cirrus and spines. The pinnate leaves are itself an adaptation to live in heavy rainfall area (pl explain how).
The cane fruits mature usually during the monsoon season or during late winter. The ripe seeds are straw-coloured. Ripeness can be judged by pressing the fruits between thumb and finger; when ripe one feel a gap between the outer cover and inner hard seed. Such fruits are collected. The fruits after collection should be thoroughly washed and cleaned off the cover and pulpy portion. This could be done by immersing the fruits in water for overnight and then rubbing with feet. The cleaned seeds are taken out and kept moist in either saw dust or sand for better viability. Drs Haridasan/Renuka, We have earlier discussed how a nursery is grown and the various processes of raising a plantation, how can we link/correlate? Should we repeat here?
Since cane seeds lose viability soon the seeds are to be sown immediately or maximum within a months time in germination bed (also known as mother bed) that are in the shade. The sowing should preferentially be done in lines and the seeds covered with a layer of sand/ soil. The bed should be regularly watered without allowing it to dry and desiccate. Seeds start germination within one month to four months. They should be pricked out and transplanted to poly bags of 5”x7” or 7”x9” size. This should be done by carefully uprooting each seedling at single-leaf stage with a shovel-like stick while taking care not to damage the seedlings in the neighbourhood. In the porposed poly pot soil a hole should be made to accommodate the roots and the seedlings should be buried upto the neck (not clear) region. It should be ensured that the seedlings continue to be in shade and are watered regularly once or twice daily as required. In about three months the seedlings should be ready to be transplanted to field.
In order to understand the variation in the fruiting and seed number, viability, germination etc. and appreciate how we need to adjust and modify how and when we carry out various processes involve in growing various cane species let us look at some rattan species of Arunachal Pradesh, a prime rattan growing area, in greater detail. l (Table )
Details of fruit type, collection time, seed weight, viability and germination haracteristics of some Rattan species – from a study in Arunachal Pradesh.''
Other than the nursery raised seedlings, seedlings that are also found naturally growing in the forest (wild seedlings) surrounding the mother plant can also be collected and used for raising seedling stock. In some sucker forming species like C. tenuis and C. leptospadix the rooted suckers can also be used for raising nursery seedlings and plantation. However these are not the preferred methods and are not cost effective. Seedlings raised for seeds and kept in the nursery bed for 12-14 months are out-planted in the field in the month of April-May (in North East India). The sites can be prepared in the winter months at least 2-3 months in advance. Since canes are shade loving plants and being climbing palms, it would be ideal to plant them under some mature trees for shade as well as support for climbing. Pits of 30 cu.cm. for planting seedlings are to be dug at a spacing of 2m x 2m, 2.5 x 2m or 4m x 4m as per requirement by clearing undergrowth. Normally there is no stem (formation) elongation for three years after which the stem will shoot up and gain height. The plantations are likely to be ready for extraction for commercial purposes wi=== As canes grow in most favourable conditions The conditions most favourable for growth of canes are unfortunately also very favourable for growth of several other plants, and hence the cane species are exposed to severe competition from aggressive weeds and gregarious herbs. For better survival of canes these weeds have to be eradicated through proper weeding. During the first and second year weeding should be carried out thrice each year. In the subsequent two years at least one weeding per year is essential. Weeding can be carried out either by 1) completely cutting/removing all the other plants from the whole plot or 2) weeding 1 meter both sides along the planted line or 3) as thali (meaning plate) cleaning, that is clearing weeds over 1 meter radius around the cane seedling. Once the stem appears and cane start climbing over the support trees, the weeding can be restricted/discontinued.
Rattan extraction and utilisation in India is, by and large, a cottage industry. Due to the belief that extraction of cane is mere cutting of stems of cane which does not require any special understanding or expertise, the cane is cut by anyone - inexperienced as well as the experienced labourers. The fact is that extreme care has to be taken while selecting the cane culms to be cut.
- Only mature culm of length between 10-20 feet should be cut; immature culms if cut might cause the plant to die, also the cane quality will be very poor.
- Care should be taken that the whole stem should be pulled out – this is difficult because of the habit of the plant but leaving portions hanging creates waste out of valuable resource.
The mature canes are collected by cutting at ground level after they attain a length of about 10-20 m. The leaf sheaths are then removed. Soon after felling, mostly thick canes are cut into 12 feet length and small diameter ones into 15-20 feet length at the felling site. The canes are then bundled into groups of 20 pieces (thick canes) or 100 pieces (thin canes) and are carried to an intermediate convenient site and piled besides the road for transportation. They are then brought to the local processing centre (LPC), where it is kept for drying in an erect position for 15-30 days. Once the cane reach the local manufacturing unit, they are further are cut into convenient sizes, and used for making furniture. Canes should be harvested in the dry winter season, because improper drying results in discolouration of canes, and once discoloured, there is no process of restoration of the desirable colour. Fresh canes of species like C. latifolius, C. nambariensis etc. contain a good quantity of water. Also when canes are harvested during the rainy season, it is not possible to dry them properly, because of the high atmospheric humidity. If the canes are properly collected, processed and marketed their quality can be considerably improved. If the canes are marketed without being properly dried or treated canes deteriorate quickly and get attacked by fungi and other pathogens. This considerably reduces the market value. During the extraction, careless scraping of the cane with a sharp knife resulting in the removal of yellow epidermis may increase the fungal attack and hence affect the aesthetic colour. Care should be taken to minimize such damage.
Check Your Progress Exercise 2