Posts Tagged 'Forests'

Western Ghats, India – The Forests

From the book  ”The Western Ghats” by Mohan Pai (2005).

 

THE FAST DISAPPEARING FORESTS

 

“There was a time when meadow, grove
and stream,

The earth and every common sight
To me did seem Apparell’d in celestial light,
The glory and the freshness of a dream.
It is not now as it had been of yore;
Turn whereso’er I may,
By night or day, the things which I have
Seen I now can see no more.”

– William Wordsworth

As in many other tropical regions throughout the world, deforestation and forest degradation due to various factors such as extension of cultivated lands, grazing of livestock, extraction of forest products, commercial plantations, road and railway building, hydroelectric projects, atomic reactors and poaching continue unabated in the Western Ghats.

There have been various estimates and guesstimates about the loss of forest cover in the Western Ghats.
* A recent study (year 2,000) says that the Western Ghats, one of India’s most prestigious “biological hotspot” has lost one-fourth of its forest cover in the last 22 years. The study which estimated changes in forest cover between 1973 and 1995 in southern parts of the Western Ghats using satellite data reveals a loss of 25.6 percent in that period. The decrease in forest can be attributed primarily to increase in plantations and agricultural areas due to population growth with Kerala observing the most rapid changes.

The study also renews the debate that despite conservation measures adopted by various agencies, the rate of deforestation has accelerated in recent years. The data shows a whopping five fold increase in forest loss from the periods 1920-60 to 1960-90. The threat seems even bigger if one considers the fact that the study does not include forest degradation and habitat fragmentation that also eventually contribute to forest loss.

The southern stretch of the Western Ghats an area of approxi-mately 40,000 sq. kms, has experienced the most significant forest loss during 1973-95. There has been a loss of 2,729 sq. kms of forests with an annual deforestation rate of 1.16 percent.
(Study by ATREE, NRSA and University of Massachusetts, USA)

* According to U.N. Food and Agricultural Organization, the area alloted to plantations in India has been increasing at an average of 15 percent a year. At this rate, if all plantations were taken from existing forests – even the sparsely covered tracts – would be destroyed in less than a quarter century.

* An earlier report by TERI, New Delhi has made the following assessment:
Very little has been documented recently about the status of the forest cover in the Western Ghats, except that it seems to have declined between 1972 and 1985 at a rate paralleling that for India as a whole, which implies a loss of cover 2.4% annually. If we extrapolate from 1986 to 1989, this means a total loss of 34% from 1972 to 1989.

Still worse is the decline of the primary forest; the amount remaining seems to be no more than 8,000 sq. kms.
All but isolated pockets of original forest have been opened up by shifting, cultivation, allowing take-over by deciduous species and bamboo among other degenerate species.

* Another study reports (Menon and Bawa 1997): Nearly 40% of the natural vegetation in the Western Ghats disappeared between 1920 and 1990. Of these 76% were converted to open or cultivated lands and 16% to coffee plantations. The rest was due to conversion to tea plantations or hydroelectric reservoirs.

* Recent studies (Ramesh and Swaminathan 1999) indicate that in the Western Ghats of Karnataka, nearly 12% of the forests have been completely lost in the past two decades. During the same period in a region like Kodagu, coffee cultivation has increased by nearly 100% with a concomitant loss of 18% forest area.

* In the state of Kerala alone, in a period of 30 years, there has been a 47% decline in evergreen/semi-evergreen forests(Prasad 1998).
Less than a century ago 40 percent of India was forested. Large tracts of deciduous and tropical rainforests in the Western Ghats region were destroyed over the past century as the British expanded India’s railway network across the country. Then, between 1951 and 1976, some 15 percent of the nations’s land were converted to cropland and much of this came from natural forest.

Forests are strained by the increasing demand of their resources. As human and livestock population swell and forests shrink, the relationship between rural communities and forest has become increasingly precarious. Nearly 90 percent of the wood taken from the forests is used as fuel. And India’s forest provide fodder for some 100 million head of cattle that trample and denude under-growth as they graze.

Yet, India’s natural forests provide it with some extremely vital services: They protect topsoil from wind and water erosion, regulate temperatures, replenish aquifers, store genetic diversity, offer recreational relief and provide a number of products other than wood – including medicine and food.

Deforestation leads to several changes in the landscape. The degradation and fragmentation of forests, which generally precede deforestation, considerably affect the biodiversity of the region. In the Western Ghats, low elevation evergreen forests dominated by Dipterocarp constitute the most threatened habitat. Its continuum along the Western Ghats has been fragmented due to selective logging, increase in permanent settlements, and rubber plantations. Consequently, several typical low-elevation species have almost become extinct, several have become rare, and some species have taken refuge in the sacred groves.

One of the major forms of human interference to vegetation and flora in the Western Ghats is the building of dams. According to published sources, there could be hundreds including small and big dams, with Maharashtra alone having 631 dams(Nair and Daniel 1986).

Hill agro-systems in the Western Ghats are today dominated by estates chiefly of tea, coffee, rubber and monocultures of various tree species, including the oil palm that was introduced lately. Available estimate indicate that above an altitude of 1,500 m in the Western Ghats, there are 750 sq. km of tea plantations. A total ofnot less than 1,500 sq. km are under coffee and 825 sq. km under cardamom. It has also been highlighted that the Nilgiri district with a total area of 2,549 sq. km has around 1,000 sq. km under various forms of cultivation.

The impact of growing coffee in the Western Ghats has been studied to some extent. According to legend, the Arabica variety was introduced at the beginning of the 17th century by a Muslim pilgrim – Baba Budan, who brought seven coffee seeds from Yemen and planted them in his hermitage in Chickmagalur, Karnataka.

Coffee plantations were then introduced in Kodagu with large scale planting of coffee near Mercara. Growing in partial shade and the traditional system adopted by people have together favoured a greater diversity of native trees in the coffee dominated agro-systems of Kodagu.

Casurina plantations first appeared in Uttara Kannada district around 1868. Teak was first raised as monoculture in 1840. The first teak plantation in Kerala was established in Nilambur in 1844. Over the years, eucalyptus, cinchona, wattle, rubber, clove, cardamom, etc. have displaced extensive patches of natural forests throughout the Western Ghats.
Apart from introduction of commercially important plants, there have been invasions by a number of aggressive alien plant species during the past 200 years in the Western Ghats. Important among these are Lantana camara (var aculeata), Eupatorium odoratum, Mikania cordata, Parthenium hysterophorus, etc. Wattle (acacia) once introduced for the extraction of tannin in the higher hills is today a major threat to the Sholas and grasslands at these altitudes. The impact of these exotic plants has been subject of lot of debate.

Large number of ornamental plants of temperate origin have also run wild in the higher elevations of the Western Ghats. Hundreds of such species have been reported both from the Palni hills and from the Nilgiris. Human influences had an adverse impact on the diversity of flowering plants in humid forests of the Western Ghats. In the Uttara Kannada district lack of coppicing ability in conjunction with their use in the wood/matchwood industry has led to disappearance of several evergreen species.

With villagers concentrating on harvest of trees in the height class of 4 – 8 m as poles and commercial interests mostly extracting trees above 16m height, there was a reduction of around 45% in all height classes between the sites of low and high level disturbance.

Unique landscapes such as Myristica swamps gave way to cultivation of rice. Along with the swamps many species of the swamp trees disappeared locally. Selective logging in the Western Ghats has had differential influence on biodiversity. When evergreen forests are thus disturbed, the woody plant species diversity has shown a gradual decline. This has been accompanied by the selective loss of certain species of greater economic value and an overall reduction in forest biomass. Other organisms have responded to human disturbance of evergreen forests rather differently. Selective logging (consequently lower tree and canopy density) has locally increased the diversity of butterflies, lizards and birds in the Western Ghats.

Top Soil & Siltation

Deforestation leads to a very sizeable loss of the top soil. It is only the forests on the slopes that prevent the run-off which takes place after heavy rains and allow water to percolate into the earth. Loss of tree cover means the top soil that is held in place by the roots of the trees becomes loose and the run-offs carry the top soil to the bottom of the river causing siltation.

Where the top soil is lost, there can be no vegetation; most deserts for instance, are what they are because the wind has blown away the top soil, and no trees can grow there any more. We cannot really ‘create’ top soil, for top soil is the product of innumerable layers of leaf litter and dead vegetable matter which disintegrate and mix with the earth. It can take anything from 500 to 1,000 years to build up one inch of new top soil. No amount of money can buy new soil. 

River Bhadra at Kalasa, Karnataka – Pic by Mohan Pai

Most loose soil from the hill slopes gets to a riverbed very fast, for in a heavy shower it travels down with the rain water or run-offs and settles down at the bottom of the riverbed, raising by a little bit, the level of the riverbed. This rising of the river bottom is called siltation and it is this which is the root cause of the floods which now we face every year. Floods are only one facet of the damage.

River Pravara near Wilson Dam, Maharashtra – Pic by Mohan Pai.

As the river bears with it its load of silt and mud out to the sea, harbours too are silted up, making it necessary to continuously carry out expensive dredging opera-tions.

The cycle of losing valuable soil, the siltation of riverbeds and consequent flooding has a strong adverse impact on the environment of the region. What is worse is that we are not only losing the invaluable soil, but large quantities of underground water as well.


River Valley Projects


The hydel potential especially of the west-flowing rivers is being utilised round the year by impounding seasonal waters behind high rise dams situated at strategic locations. To utilise the available head, water is channeled through penstocks to turbines in power houses. Penstocks in earlier projects as at Sharavathy in Karnataka and Khopoli in Maharashtra were on the surface.


Wilson Dam, Bhandardara, Maharashtra – Pic by Mohan Pai

In recent years penstocks have been laid in steep tunnels bored into rocky mountains. Idduki in Kerala and Nagjahri on the Kali have covered penstocks. The power houses also have gone underground as at Idduki and Varahi where they are within the mountain. Hydel generation is considered to be clean and relatively cheap. The environmental costs of hydel projects are, however, high though not easily quantifiable. The environmental issues of hydel projects are site specific but many are common. The following is a list of some common issues:

1. Submersion of large scale vegetation by the reservoir.
2. Degradation of forests due to quarries, roads, power lines and housing colonies.
3. Disturbance to wildlife during construction and change of the habitat after the construction.
4. Siltation of the reservoirs due to inadequate catchment area management.
5. Possibility of reservoir induced seismicity.
6. Cumulative impact of a series of dams and reservoirs in close proximity.
7. Displacement of people and lack of proper rehabilitation.
8. Impact on riparian communities when the pattern of river f low is changed or the water of one river basin is diverted to another basin.
9. Increase in salinity due to ingress of sea water, especially when water of a river is diverted to another basin.
10. Cumulative impact of all developmental activities in a particular region of the Western Ghats.

Submersion of Vegetation

The water impounded by the high dams generally submerge large tracts of evergreen forests of the western valleys. Linganamakki reservoir of the Sharavathy hydel project in Karnataka submerged 326.3 sq. km, mostly covered by luxuriant forests.

Harangi Dam Reservoir, Kodagu

 In order to increase the quantity of stored water, auxiliary dams were constructed. The waters from Savehakkalu and Chakra further reduced the forest cover in Shimoga district of Karnataka. The Periyar basin in the High Ranges of Kerala has a series of 12 large dams which directly or indirectly resulted in destruction of about 4000 sq. km of rainforests and grasslands. Kali river with 6 major dams has submerged about 32,000 acres of prime forests in Uttara Kannada district. As hydel projects are being multiplied more forests are being lost. The compensatory afforestation programmes in arid areas do not compensate for the loss of rich evergreen and moist deciduous forests of the Western Ghats.

Colonies, quarries, roads and power lines

At peak construction activities, the work force at Sharavathy was around 50,000. Housing colonies were set up after denuding the surrounding hills. During the Kali stage, the township of Ambikanagar in Uttara Kannada was located in an area that still then was covered by dense forests. Before handing over the area to Karnataka Power Corporation, the forest department removed all the trees and handed over a totally denuded area. A similar denudation occurred at Ramanagara, the rehabilitation area for the Supa reservoir oustees .

Supa Reservoir on Kali Nadi, Karnataka – Pic by Mohan Pai

Degradation of wildlife habitats

The Western Ghats have a rich fauna. Herds of elephants, gaur and deer, flock of birds, many species of reptiles and amphibians, to mention a few, have inhabited these forests. The blasting of rocks, the rumble of heavy machinery, the incursion by humans have greatly reduced the fauna of the Ghats. These activities have also fragmented the forests to a large extent.
The change in river flow patterns so essential to spawning and migration of fishes has resulted in a drastic reduction of aquatic fauna. The lack of fish ladders in most dams confines fishes to particular areas and prevents normal movements. Studies have shown a marked reduction in aquatic fauna.

Siltation of reservoirs

The slopes of the Western Ghats are steep. The rainfall is heavy during the monsoon. Once the forest cover is lost and the grasslands are disturbed, run-off and soil erosion is high. Other activities in the catchment area increase the silt load. The Kali river valley schemes afford matter for a case study. In addition to 6 large dams, this area has nine active mining operations with scarcely any measure for controlling mine run-off and soil erosion from tailing dumps. Each of the mines contributes to the silt-load of the river. The water holding capacity of each reservoir is being reduced by this siltation.
Reservoir induced seismicity
Seepage and pressure built up by a large mass of water are known to induce seismicity. In order to monitor seismic movements and dam vibrations new techniques are being adopted. The double arch dam at Idduki has a number of sensors embedded in it. Most dams in the Western Ghats do not have such monitoring devices. Reservoir induced tremors and earthquakes in the Koyna region were felt several hundred km away from its epicentre. Had the dam collapsed, several downstream towns would have been washed away.

Cumulative impact

The environmental issues relating to hydel projects become more pronounced when a river has a series of dams or, when several basins in close proximity are taken up for power generation. The Sharavathy and Kali basins have a concentration of hydel projects. The series of dams and reservoirs alter the riparian ecology and biodiversity. The biota of a natural river bank cannot survive on the artificial shores of a reservoir. The cumulative impact of several projects has to be examined. As indicated earlier, the Sharavathy with its many dams and reservoirs destroyed extensive forests in Shimoga district. The Kali project has ruined a rich game sanctuary. The Koyna project resulted in seismic disturbances.

 

Mattupetty Dam Reservoir , Kerala – Pic by Mohan Pai

Silent Valley in the Western Ghats is a concrete example of abandoning the project due to prudence. The plans to submerge the Silent Valley caused a lot of agitation among conservationists. The scheme was to build a dam 390 ft high and 720 ft wide which would be used for the generation of 120 MW of hydroelectric power and would irrigate 5,000 acres of land. In this instance the conservationists were quite sure that the amount of damage that would be done by constructing the dam would be out of proportion to the advantages gained. The balance sheet was simple. The evergreen rain forests of the Silent Valley which would be submerged by the dam, was the kind which has evolved over thousands of years; there were few comparable areas of such forest left in India, and, once it went, it would mean that we had lost not only the forest itself, but hundreds of plant species which had not yet been studied. Fortunately the pressure from conservationists resulted in project being dropped. However, there is a recent move by the Government of Kerala to reopen the Silent Valley Project with a dam on Kunthipuza river.

Displacement and resettlement

Several studies have been made on displacement of people due to land acquisition and land submersion. The hydel reservoirs in the Western Ghats have displaced many thousand of people especially tribals and agriculturists. For example, the Kali project in Karnataka displaced 1,665 families, The Savehakkalu and Chakra projects displaced 227 families, the Varahi 1,361 families.

The trauma of displacement is made more painful by the inadequacy of the legal and financial provisions. Especially the displaced tribals go without any compensation. The socio-cultural environment of displaced communities is shattered. Their means of livelihood are undermined. Skills have to be learned once again as they shift from non-market economy to a competitive market based economy.

The responsibility of resettling displaced people is that of various departments of the State and Central Governments. Legislation to ensure justice to the displaced is weak and outmoded. There is a strong feeling among the displaced that “Peter is being robbed to pay Paul”.

Impact on riparian communities by changes in river flow

At the peak of the S-W Monsoon, the crest gates of the dams are opened to release excess water. The sudden release have affected the people living along the river banks. The situation can be so critical that the army has been called upon to rescue the marooned people. Sometimes the hydel projects are so designed that water from one river basin is diverted to another.
For example the double arched dam sealed the Periyar. The water in the reservoir is being diverted to the power house at Moolamattom. The tail race from the power house meets the Muvattapuzha river, leaving the Periyar with highly reduced flow. This has adversely affected the communities along the Periyar banks. A similar situation has resulted by the westward diversion of the waters of the eastward flowing Koyna river.

Increase in salinity due to ingress of sea waters

When there is reduction in flow of a river due to diversion of its water, the river in its lower reaches is not sufficiently flushed by the monsoon rains. Thus there is acute scarcity of fresh water at Ernakulam because of ingress of sea water after the construction of Idukki dam.

Cumulative impact of developmental activities

There are different activities going on simultaneously in the Western Ghats. Besides the hydel projects, irrigation projects are also implemented. Surface mining is taken up both within the forest and outside them. The controversial Kaiga Nuclear Power station, the only nuclear plant in a forest in the world is located at Kadri in the Kali river basin. There are traditional activities of forestry, agri-culture, horticulture. Plantations of coffee, tea, cardamom, pepper, rubber and ginger are being expanded. The cumulative effect of all these activities seriously threatens the ecosystems of the Western Ghats and undermines the resource base in this mountain range.

Irrigation Projects

In order to conserve seasonal waters of the east-flowing rivers, innumerable dams both big and small have been constructed in the Western Ghats and in the peninsular India. These are classified as large, medium and small irrigation projects. Only the large and medium irrigation works are being considered here. The Western Ghats merge with the Deccan plateau on the eastern side. They descend gradually from the ridge forming shallow valleys. Where the rivers flow through a narrow neck formed by the hills, dams are constructed to impound the water which is then conveyed over long distances by canals. The submergence of these valleys is of great consequence.

The moist deciduous forests are rich in timber species like rose-wood, teak, venteak. The fauna is varied and abundant. Many of the wildlife sanctuaries are located here. Plantations of coffee and tea, gardens of areca and pepper, orchards with a variety of fruit trees thrive well in these valleys. Flourishing agricultural communities have occupied the area and harvested cereals and pulses. Several studies have been carried out on the impact of these irrigation dams in the Western Ghat. Some of the environmental issues associated with these dams are common to hydel projects. Some are specific to the projects in the shallow valleys in the rain shadow area of the Ghats.

Deforestation and the Global Carbon Cycle

Carbon dioxide ( CO2) is the major gas involved in the greenhouse effect, which causes global warming. All the things that produce CO2 (like car burning gas) and the things that consume Co2 (growing plants) are involved in the “global carbon cycle”.

Tropical forests hold an immense amount of carbon, which joins with oxygen to form CO2. The plants and soil of tropical forests hold 460-575 billion metric tons of carbon worldwide. Each acre of tropical forest stores about 180 metric tons of carbon.

Deforestation increases the amount of CO2 and other trace gases in the atmosphere. When a forest is cut and replaced by cropland and pastures, the carbon that was stored in the tree trunks (wood is about 50% carbon) joins with oxygen and is released into the atmosphere as CO2.

The loss of forests has a great effect on the global carbon cycle. From 1850 to 1990, deforestation worldwide (including that in the United States) released 122 billion metric tons of carbon into the atmosphere, with the current rate being 1.6 billion metric tons per year. In comparison all the fossil fuels (coal, oil and gas) burned during a year release about 6 billion tons per year.

Releasing CO2 into the atmosphere increases the greenhouse effect, and may raise global temperature. The role of fossil fuels burned by cars and industry is well known, but tropical deforestation releases about 25% of the amount released by fossil fuel burning. Tropical deforestation, therefore, contributes a significant part of the increasing CO2 in the atmosphere.


Blog Stats

  • 62,860 hits

Top Clicks

  • None

Flickr Photos

Intentional Blur

Macro Monday 2017-04-20 (5D_32A6865)

"Intentional Blur"

More Photos

Top Rated