P. S. Roy & P. K. Joshi
Indian Institute of Remote Sensing (NRSA)
4, Kalidas Road, Dehradun – 248001
The northeastern part of India, known for its diverse and most extensive lush forest cover, is sadly one of the major regions facing severe deforestation. Forests of this region are unique structurally and species composition. It is a meeting region of temperate east Himalayan flora, palaeo-arctic flora of Tibetan highland and wet evergreen flora of south-east Asia and Yunnan forming bowl of biodiversity. One of the state of this region viz., Arunachal Pradesh occupies a significant place as a crucible for the evolution of flora in north-east India and for speciation. The Brahmaputra valley sandwitched between eastern Himalaya in the north, Garo/Khasi/Jaintia and Mikir/Cachar/Barail hills ranges in the south; is a meeting ground of the temperate east Himalayan flora and the wet evergreen and wet deciduous floristic elements. The Khasi-Jaintia hills function as a corridor of the south-east Asia floristic elements into the Indian subcontinent through the Arakan arc. The altitudinal variation and rainfall patterns of southwest and northeast monsoon play a significant role in the development of ecological niches in this region of India.
According to an official estimate based on satellite images (survey report of FSI), northeastern region has 1,63,799 km2 of forest, which is about 25% of the total forest cover in the country (Anon., 2000). The management of the forest has suffered in the recent past due to pressure on land, decreasing cycle of shifting cultivation, exploitation of forest for timber and lack of scientific management strategy. The age-old practice of shifting cultivation has been a single factor responsible for the forest and land degradation, thereby changing the landscape extensively. About 0.45 million families in northeastern region annually cultivate 10,000 km2 forests whereas total area affected by ‘jhumming’ is believed to be 44,000 km2 (Singh, 1990). Degraded secondary forests, bamboo thickets and weeds or simply barren land dominate today’s ‘jhumscapes’ (Toky and Ramakrishanan, 1981; Roy and Joshi, 2002).
Fig. 1. Vegetation Type Map of Northeast India (Source: DOS-DBT Project)
Prepared by: Indian Institute of Remote Sensing (NRSA), Dehradun
Regional Remote Sensing Agency (B)
Regional Remote Sensing Agency (D)
Regional Remote Sensing Agency (K)
Further, the problem has been getting worse through the indiscriminate felling of trees to satisfy the ever-growing hunger of industries surviving on forest products such as paper and pulp, plywood, match stick, etc. There is an urgent need of policy measures to undo the massive losses to the green cover of this region. Unlike other regions of the country administrative control regimes of forest cover in Northeast is different (Table 1). A large part of the forests in this area fall under the category of open forests with a crown density of 10-40% and only few areas qualify as dense forests i.e. of crown density of 40% or higher. According to 1995 estimates, these states including Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram, Nagaland and Sikkim accounted for a loss of 791 sq. km forest area in two years viz. from 1993 to 1995 (FSI, 1996).
|State||Total||Reserved||Protected||Unclassified||Total||Shifting Cultivation (1987-97)|
The present paper highlights the pattern of changes being experienced by the northeast region as analysed by modern mapping tools like remote sensing and geoinformatics.
Fig. 2. Landscape Dynamics in Meghalaya (Talukdar et al., 2001)
Forest Landscape Characterisation in Northeast India
In a project entitled ‘Biodiversity Characterisation at Landscape Level in North-East India using Satellite Remote Sensing and Geographical Information System’ various forest vegetation types were classified and mapped with high accuracy using satellite remote sensing technology (Anon., 2002). The project is a pioneering effort to create geospatial database on vegetation cover types, fragmentation, disturbance regimes and biological richness. The landscape ecological principles have provided insight to the natural and human indices factors, which may bring dynamics in the forested landscape of the region. Twenty one forest vegetation cover types and seven associated forest vegetation types were mapped. The account of the land use cover is given in Table 2.
|Land cover||States||Area (km2)||Area (%)|
|Tropical Evergreen Forest||Nagaland, Arunachal Pradesh,Assam, Mizoram, Tripura||5246.202||2.001|
|Arunachal Pradesh, Assam||980.87||0.374|
|Tropical Semi-Evergreen Forest||Manipur, Nagaland, Arunachal Pradesh, Assam, Meghalaya, Mizoram||15363.42||5.86|
|Moist Deciduous Forest||Manipur, Nagaland, Arunachal Pradesh, Assam, Meghalaya, Tripura||19727.24||7.524|
|Hollock (Terminalia sp.)||Arunachal Pradesh||108.87||0.042|
|Sal (Shorea robusta) forest||Sikkim, Assam, Meghalaya, Tripura||526.61||0.201|
|Teak (Tectona grandis) Plantation||Assam||15.71||0.006|
|Dry Deciduous||Forest Manipur||79.00||0.03|
|Subtropical Evergreen I||Arunachal Pradesh, Meghalaya||20866.83||7.959|
|Subtropical Evergreen II||Arunachal Pradesh||3559.08||1.358|
|Sub-Tropical Broad leaved Forest||Mizoram||509.95||0.195|
|Broad-leaved Hill Forest||Sikkim||1876.18||0.716|
|Pine Forest||Manipur, Nagaland, Arunachal Pradesh, Assam, Meghalaya||1647.27||0.628|
|Temperate Broadleaved||Arunachal Pradesh||20785.02||7.928|
|Mixed Temperate Forest||Nagaland||509.95||0.195|
|Wet Temperate Forest||Mizoram||448.16||0.171|
|Temperate Coniferous Forest||Arunachal Pradesh||3190.60||1.217|
|Fir Forest||Arunachal Pradesh||159.11||0.061|
|Sub-alpine and Rhododendron||Sikkim, Arunachal Pradesh,||276.35||0.105|
|Associated vegetation type
|Manipur, Nagaland, Arunachal Pradesh
Assam, Meghalaya, Mizoram, Tripura.
|Open Bamboo Brakes||Nagaland, Arunachal Pradesh, Meghalaya, Mizoram, Tripura||9501.57||3.624|
|Degraded Forest||Arunachal Pradesh, Assam, Meghalaya, Mizoram, Tripura||15189.12||5.793|
|Subalpine and alpine Scrub||Arunachal Pradesh, Sikkim||2654.88||1.013|
|Alpine Pastures||Arunachal Pradesh, Sikkim||4697.66||1.792|
|Other Grasslands||Assam, Meghalya||1971.18||0.752|
|Orchards (including tea gardens)||Arunachal Pradesh and Assam||6896.67||2.631|
|Non-forest/Current shifting cultivation/Fallow/Barren/ Alpine Barren/Agriculture/ Settlement/Others||Arunachal Pradesh, Assam, Mizoram, Tripura,Nagaland, Sikkim, Manipur, MeghalyaArunachal Pradesh, Sikkim, Manipur||83032.75||31.67|
|Water Body||Arunachal Pradesh, Assam, Mizoram,Tripura,Nagaland, Sikkim, Manipur, Meghalya||4320.07||1.648|
Over-exploitation, habitat loss and fragmentation are the three major factors that threaten the biodiversity of this region. Different forest vegetation types mapped were primarily based on their spectral response. Stages of abandoned jhum lands were mapped under one class, however, the fresh shifting cultivation/denuded areas were mapped separately.
The classifications of forest types given by Champion and Seth (1968) are based on ground observations. Their extent and actual state had not been mapped so far. The satellite-based mapping has succeeded in overcoming the information gap. This classification is based on spectral characteristics of vegetation supplemented by extensive field survey. The present mapping has provided the exact extent and distribution of various forest vegetation types at 1: 250 000 scale.
This study has also helped in assessing the extent of shifting cultivation and its role both as a factor in the degradation and loss of neighbouring forests. The findings revealed that high fragmented forest have fewer plant species, reduced anthropogenic use evidence and newer community types than medium and low fragment forests. Simpler terrain encourages anthropogenic uses thus leading to forest loss. The study is in the line of expectations that fragmentation reduces diversity. The nature of forest fragmentation in these landscapes is mainly attributed to shifting cultivation, elicit felling and deforestation for creating agricultural lands.
|Land use category||1980||1989||1995|
Temporal changes in Meghalaya
The comparative status of the forest cover of Meghalaya during 1980 to 1995 has been shown in Table 3. The forest cover of Meghalaya has been decreased during this time period. The exact figures of the total forest cover in 1980 could not be ascertained because of the more cloud cover: 769.95 sqkm (3.43%). The forest cover of Meghalya has decreased during 1980-1995. The trend of forest cover shows that during 1980-89, maximum deforestation has been done. However, the negative trends during 1989-1995 show that the deforestation process has slowed down (Fig. 2).
The degradational activities viz., shifting cultivation clear felling of forests for timber and mining has altered the natural landscape to a great extent. This has resulted in fragmentation of the landscape and loss of many endemic species of the state (Haridasan and Rao, 1985). There has been significant increase in landscape variability during 1980 – 1995. The land transformations result in the alternation of natural habitats. These changes have brought in impacts like fragmentation, loss of biodiversity and degradation of sites. Spatial presentation of landscape dynamics can be used to infer disturbance regimes horizontally. Higher land cover dynamics has been observed in Garo hills showing more alternations in the landscape during the study period. For example unique plant species such as Cycas pectinata and Dipteris wallichi were lost in Meghalaya (Kataki, 1983). Also species such as Diospyros undulata, Nymphaea pygmaea and Sageretia hamosa are still considered extinct and luvunga scandens is thought to be locally extinct (Khan et al., 1997; Roy and Tomar, 2000).
Fig. 3. Largescale deforestation in Sonitpur (Assam) (Anon. 2001)
Largescale deforestation – Sonitpur (Assam)
One of the most aggressive largescale deforestation in the foothill region of Eastern Himalayas has been found to take place in Sonitpur district of Assam. The spatial distribution of different forest types from 1994 to 2000 show that very valuable forest cover area is being converted to agricultural land (Srivastavata et al., 2002). The reduction in total forests is more from 1999 to 2000 than was observed from 1994 to 1999. 86.75 sq km (1.70%) of forest area has changed from 1994 to 1999 while 145.44 sq km (2.86%) has changed from 1999 to 2000. The massive change in the forest cover is due to human induced practices and unsound forest management activities. It is the highest rate of deforestation recorded in the managed setup. Even the community participation in these regions has failed to affect protection and conservation of the area. The changes have not only impacted the cover attributes but also the biodiversity of the area. The expected loss in the biodiversity is quite significant (Fig. 2, Table 3).
Impacts of Shifting Cultivation
In one of the international initiatives TREES – II, the shifting cultivation practices in northeast India have been assessed. The three test sites in Arunachal Pradesh (Tirap, Patki and Hilla), Nagaland, and the Barak valley were compared between 1991 and 1996. It is revealed by the study that area under permanent agriculture has almost been constant, the increase is only in semi-permanent agriculture, witnessing an increased extent of shifting cultivation in the region. In a shifting cultivation landscape, the bamboo invades and later is replaced by the secondary forest. In the past with sufficiently long fallow periods to 20-30 years the system was sustainable but with the reduction in the fallow period of as low as 3 years in recent times the situation has attracted the attention of decision-makers and planners. However, due to the human pressure and ill management practices not only the primary forests but also the secondary forests are being cleared. There is an extremely frequent change of mosaics into non-forests natural vegetation and vice-versa, showing that re-growth of forests is almost nil and since existing forests are also decreasing, the threat to which the forests are being subjected to is of immediate concern (Roy et al., 2002).
Fig. 4 Land Use Land Cover change in Sonitpur (Assam) (Srivastava et al., 2002)
Forest and forest ecosystems of north-east India are under severe pressures, both from biotic and abiotic factors, due to population explosion, encroachments on forest lands, loss of forest cover for other non-forest uses, shifting cultivation practices and degradation caused by illicit felling, lopping for fuelwood forest and fodder, removal of forest cover for litter, forest fires etc. Given the rich biodiversity of this region, its conservation has become a major challenge. Studies have identified that four general factors leading to forest fragmentation in the northeast regions are – jhum cultivation, human population pressure, industrial logging and weak government policies.
The socio-political situation is playing a very important role in the deforestation rates in spatial and temporal domain. The Hollock and Hollong forests of the northeastern Himalayan region have been cleared with the highest rate. The sustainable forest management in this region prescribes 60-80 rotation cycle. However in absence of any management plan, estimate of growing stock and stratification on site quality, the exploitation of wet tropical evergreen forest is left to timber mafias. The rate of deforestation is much higher than this. The apex court imposed an interim ban on felling in forests on December 12, 1996. Being the owner of India’s one-fourth of forests in the fragile location, the region has to be restored and the resources are to be used in a sustainable way. The order has come at a very proper time wherein the region was losing 31,700 hectares of forest every year, mostly due to government and traders’ nexus (Anon., 2002b). Most of the forest (80%) in the region is controlled by the traditional community. The concept of people’s participation has failed in the region to restore the natural resource and its optimum utilisation. Non-scientific forest management practices have resulted in the fragmentation of the landscape in the region. The permit system, introduced to help the local people, has become instrumental for siphoning huge number of trees out the region. The rampant felling has changed the scenario of the dense evergreen forest to denudation. Except few parts of Arunanachal Pradesh, the whole region is harbouring only the open or degraded forest. The present image of the regions’ forested landscape is due to the non-scientific and weak management polices. About 50 saw mills are actively functioning in the Assam and Arunanchal Pradesh forest belt. Are these forest-based industries set up on the basis of available raw material in the catchment? The sawmills, mostly owned by influential socio-political set ups, used to continue operations long after their quotas were over. The number of sawmills in Arunanchal Pradesh increased by 400 percent from 1983 to 1994 (Anon., 2002b). In some places saw mills are located deep in the forests, making them inaccessible. The illegal timber seized from the entire region is estimated to run into several hundred crore rupees per year. In the forests depots, there is about 0.12 million cum of such illicit timber (Anon., 2002b). Since most of the timber stock is illegal, it is impossible to prepare an inventory, a process mandatory for its disposal. Moreover it is feared that new timber is being used to replace the old stock.
The ban has been imposed to restore the fragile and most unique ecosystem of the nation. It says that forests should be operated based on scientific management. It has been misinterpreted on account of financial losses, unemployment and the livelihood issues. The local communities claim to use only 1% of the forest resource for their livelihood, but hillocks have been leased to traders at throwaway prices. Recently the Sonitpur district of Assam has experienced the highest rate of deforestation. The joint forest management was not found of much value in this region. The community forest and the private forest practices could not preserve much of the areas. The unique land ownership system could not manage the community forest or exercise any control on the over-utilisation of the resources. It can only be achieved with a scientific-cum- social management practice. A complete inventory of the total forest areas and growing stock is thus a task of the highest priority. Stratification is required at the growth level as well as the individual tree level. It is required to develop systematic database on geoinformation of the entire region. The established database will provide resource availability, requirement and utilisation pattern. The per unit growing stock assessment vis a vis requirement of the timber production need to be estimated. The pioneering effort made by the Department of Space and Department of Technology project is a beginning of the baseline information which can be used for evolving a scientific management plan.
|Forest Types||No. of Samples||Species Diversity||Total No. of Species||Economically Important Species||Medicinally Important Species||Endemic Species|
Scientific management would need comprehensive information on varying scale, forest cover type, resource component, land use practices, socio-economic set up and administrative details in the format of national geospatial data frame. Remote sensing based database should finally help the effort of saving forest resources of Northeast.
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