heavy rainfall

Vegetation of Sikkim for Sikkim PSC

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Vegetation of Sikkim

  • Sikkim provides a great variety of habitats, that support and sustains rich flora and fauna.
  • The Vegetation of Sikkim changes from tropical to subtropical upwards through middle hills with much coniferous and Oak forests of temperate character to the higher slopes with sub alpine scrub and alpine “meadows” generally related to higher alpine flora of the north temperate zone.
  • Sikkim has been known to be the most humid region in the whole range of Himalaya, because of its proximity to the Bay of Bengal and direct exposure to the south-west monsoon.
  • The annual rainfall ranges from 200 – 500 cm in most of its inner valleys except for its northern most region which receives scanty rainfall.
  • Throughout the year, but particularly from June to September, monsoon brings heavy rainfall to the state.
  • Lower hills and valleys enjoy a sub tropical climate, warm in winter, hot and extremely humid in summer.
  • Towards interior the climate becomes gradually more temperate.

Flowering Plants of Sikkim

  • Sikkim is one of the biodiversity rich states of our country.
  • The flowering plant diversity Sof the state with some indicative figures of dominant genera like Bulbophyllum, Calanthe, Coelogyne, Cymbidium, Dendrobium, Gentiana, Juncus, Pedicularis, Primula, Rhododendron and Swertia recorded from the region.Vegetation of Sikkim
  • Nearly 165 species have been named after the state, as they were first collected from the state or plants were known to occur in Vegetation of Sikkim.
  • Some of the representative endemic species of the state have also been listed.
  • One hundred ninety seven families, 1371 genera have been appended with indicative number of species of each genus known to occur in Vegetation of Sikkim.
  • In all more than 4450 species of flowering plants recorded so far.

 

Biodiversity of Vegetation of Sikkim

  • India is recognized as one of the 12 mega diversity centres of the world. Out of the 18 Biodiversity hot-spots in the world, India owns 2, namely the Western Ghats and the Eastern Himalayas.
  • Sikkim covering just 0.2 % of the geographical area of the country has tremendous biodiversity and has been identified as one of the HOT-SPOT in the Eastern Himalayas.
  • There are 10 bio-geographic zones & 25 biotic provinces— which have 16 major forests types & > 200 sub types as per (Champion & Seth 1968).
  • Sikkim falls under Himalayan (2) Bio-geographic zone & Central Himalaya (2c) biotic province—-having about 9 types of forests types (Champion & Seth).
  • The State is endowed with rich floral and faunal diversity. Species wise, the State harbors over 4500 flowering plants, 550 Orchids, 36 Rhododendrons, 16 Conifers, 28 Bamboos, 362 Ferns and its allies, 9 Tree Ferns, 30 Primulas, 11 Oaks, over 424 Medicinal plants, 144+ mammals, 550 Birds, 48 Fishes and over 600 Butterflies.
  • While these figures are still not absolute, it may be kept in mind that this is only the mega-fauna and flora.
  • The tremendous diversity of insects like beetles and moths as well as a host of other life forms is yet to be enumerated.
  • Most of the high altitude medicinal plants are rare and endangered species.
  • Sikkim also has 28 Mountains/Peaks, more than 80 Glaciers, 227 high altitude lakes/wetlands and over 104 rivers and streams.
  • Nature has been particularly generous in her gift of sylvan treasures to the state of Sikkim.
  • Luxuriant forest, abound in all part of state and variety of medicinal plants, herbs, shrubs, bamboos and trees growing in state is truly rich.
  • In the forest, there are number of plants whose medicinal values have been well recognized by local people as well as by different pharmaceutical, insecticidal and perfumery sectors.
  • Medicinal plants ought to be given the status of a “National Resources” because their sustained availability is essential to sustain one of the world’s oldest medicinal traditions, a priceless legacy of the Indian people.
  • The local inhabitants for treatment of various ailments use numerous herbal remedies.
  • Modern medicines owes to the flora of these mountains.
  • Many inhabitants for treatment of various ailments use numerous herbal remedies.
  • Many species of Himalayan origin have revolutionized the allopathic systems of medicine

Forest and Forestry of Vegetation of Sikkim

  • Forest is one of the richest natural resources of Vegetation of Sikkim.
  • With luxuriant forest abounding in all part of state, Forestry has been the major land use in the State and 82.31% of the total geographical area of the State is under the administrative control of the State Forest Department.Vegetation of Sikkim
  • The total forest and tree cover of the State is 3392 sq. km (47.80% of the total geographical area of the state).
  • The composition ranges from tropical Dry Deciduous Forests with Sal and its associates in the valleys of Teesta and Rangit to the Alpine Scrub and grassland in high altitude.

Forest Type of Vegetation of Sikkim

S.No. Groups Characteristic of Species Altitude (Mts) Places
1. Tropical Moist Deciduous Forest
 Tropical Moist Deciduous Forest 1.      Dillenia pentagyna

2.      Dysoxylum floribundum

3.      Gymnema arborea

4.      Lagerostroemia patviflora

5.      Shorea robusta

6.      Toona ciliata

 250-900 Rangpo Chhu, Sherwani,  Jorethang, Rangit
2. Sub-Tropical Forest      
Sub-Tropical Broad Leaved  Forest 1.      Albizia procera,

2.      Alnus Nepalensis,

3.      Bauhinia purpurea

4.      Castanopsis indica, 

5.      Macaranga denticulate

6.      Michelia champaca,

7.      Schima wallichii

 1000-2000 Tong,Gyalzing, Sangklang Selem Chakung Chhu.
ii)Sub Tropical Pine forests 1.      Pinus roxburghii,

2.       Engelhardtia colebrookiana

3.      Quercus leucotrichophora

 1000-1800 Gangtok, Gyalzing,     Rongli
3. Montantane Wet Temperate Forest
i)Temperate
Broad Leaved
Forests		 1.      Acer campbellii,

2.      Engelhardtia spicata,

3.      Machilus edulis,

4.      Michelia cathcartii,

5.      Quercus lamellose,

6.      Taxus baccata

 1700-2700 Chunthang- Lachung, Yumthang
ii)Mixed Coniferous
temperate forest
Forest		 1.      Abies densa,        

2.      Acer campbellii,

3.        Betula utiis,

4.       Rhododendron,  arboreum,

5.      Abies densa,

6.      Taxus baccata,

7.      Tsuga dumosa,   

8.      Larix   griffithianum

 2700-3000 Lachen, Zemu, Yathang, Lachung
4. Sub-Alpine Forest
 Sub-Alpine Forest 1.      Abies densa,

2.       Betula utiis

3.       Casiope fastigata

4.       Rhododendron sp.

 Above 3000 Above Yathang
5. Moist Alpine
i) Birch-  Rhododendron  Scrub Forest 1.      Betula utilis,

2.      Sorbus foliolosa,

3.      Rhododendron campanulatum,

 Above 3600 Thangu, Maiminchu
ii) Deciduous
Alpine Scrub		 1.      Betula utilis, 

2.      Berberis sp.,

3.       Lonicera sp., 

4.      Rosa sp

 3600-3900 Changu      Thangu
iii) Dwarf Rhododen ron  Scrub 1.      Rhododendron lepidotum Above 3600 Thangu
iv) Alpine pastures 1.      Allium,

2.      Anemone,

3.      Delphinium

 Above 4000 Chopta  Yumasong
b) Dry Alpine Scrub      
 i) Dwarf Juniperous scrub 1.      Juniperusrecurva  

2.      J. wallichiana

 Above 3600 Chopta    Chhangu
ii) Dry alpine scrub 1.      Ephedra gerardiana,

2.       Meconopsis sp., 

3.      Ribes sp.

 Above 4000 Chopta

 

 

 

Climate of Sikkim for Sikkim PSC

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Climate of Sikkim

  • The Climate of Sikkim is extremely varied largely due to variation in altitude.
  • It has the Himalayan or high mountain type of climate.
  • Altitude is the most important factor controlling the climate and weather condition here.
  • Relief features such as high mountains act as the barriers for the movements of monsoon winds.
  • Low temperature, high rainfall on windward slopes, comparatively dry on the leeward side and heavy precipitation in the form of snow at the mountain top are the main features of the Climate of Sikkim.
  • Due to great variation in sharp edged mountains throughout the state, there is large variation in rainfall and temperature.
  • The Himalayas act as barrier to monsoon winds forcing them to ascend therebClimate of Sikkimy causing orographic rainfall and snow fall.
  • The Himalayas also act as barrier to the flow of cold winds from Central Asia, resulting heavy snowfall on the mountain tops and higher elevations and dry winter season at lower elevation located at the leeward side.
  • The monsoon winds dominate the Climate of Sikkim.
  • There is seasonal reversal of winds almost throughout the Climate of Sikkim.
  • The monsoon imposes the seasonal rhythm which is apparent in the activities of the people since most of them are agriculturists.
  • The following four seasons are prevalent on the basis of the monsoon circulation over the state.
  1. The cold weather season – December to February
  2. The spring weather season – March to May
  3. The south-west monsoon – June to September
  4. The period of retreating monsoon – October to November

 

 

Rainfall and temperature of Climate of Sikkim

  • The mean annual rainfall varies from 2000 mm. to 4000 mm. with intensity of rain from drizzling showers in lower altitude to torrential rains in higher altitude.
  • There are two maximum rainfall areas (i) South-East region and (ii) South-West region.
  • There is an area in the North-West region which gets very little rainfall.
  • The greater part of rain fall is received during May to September.
  • The annual rainfall of Sikkim is 2739 mm.
  • The temperature varies with the altitude and slope aspect.
  • The mean temperature in the lower altitudinal zone, it varies from 1.5 degree centigrade to 9.5 degree centigrade.
  • The maximum temperature is usually recorded during July-August which varies from 21 Degree Celsius to 26 Degree Celsius and minimum during December-January between 6 Degree Celsius and 8 Degree Celsius.
  • Fog is a common feature in the entire state from May to September.
  • Biting cold is experienced at high altitude places in the winter months and snowfall is also not uncommon during this period.
  • Climatic factors are entirely influenced by altitude.
S. No. Station Maximum Temperature (Degree Centigrade) Minimum Temperature

(Degree Centigrade)

 Rainfall (millimeter)
1 Gangtok 18.8 12.7 3589.5
2 Mangan 25.5 15.3 3244.1
3 Mazitar 29.4 17.3 1620.2
4 Namthang 32.1 14.0 1972.0

 

 

 

 

Climatic types in Climate of Sikkim

  1. Snow Peak Type:
  • This climate conforms to altitude of 4001 meters or more above the mean sea level.
  • The mountain peaks are mostly covered by snow. Precipitation is mainly through snowfall.
  • Cultivable land is not available in this climatic type.
  • Vegetation is mainly herbs or medicinal herbs.

 

  1. Densely forested hill type:
  • These climatic conditions are found between 2701 metres and 4000 metres above the mean sea level.
  • The land has dense vegetation with tall trees and variety of rhododendron and primula flowers.
  • It is mostly covered by snow during winter season and precipitation is through snow and heavy rainfall during summer.
  • Winter is extremely cold. Potato and cabbage are cultivated during summer months at Thangu, Lachen and Lachung in North District.

 

  1. Very high hill type:
  • Such climatic conditions are associated with the height between 1701 metres and 2700 metres above the mean sea level.
  • Snow fall is common during winter months, i.e. December to February and heavy rainfall during June-July.
  • This climate is suitable for seed potato growing. Other alternative crops are temperate fruit plants cabbage, peas, radish and other vegetables.
  • Soyabeans, high altitude maize and off season cabbage cultivation is common.
  • Lachen, Lachung, Ravongla, Damthang, Phadamchen, Zuluk, Okhrey, Hilley, Bhareng and Ribdi are the important areas in this climatic type.

 

  1. High hill type:
  • The climate between 1501 metres and 1700 metres above the mean sea level falls under this category.
  • Precipitation is mainly through rainfall.
  • This is essentially a large cardamom growing belt.
  • Other important crops of the zone are the maize, peas, millets, vegetables etc. Usually, this is essentially a dry weather with occasional drizzling in winter and heavy rainfalls in summer.

 

  1. Mid hill type:
  • Such climate is found between 881 metres and 1500 metres above the mean sea level.
  • This is essentially an orange belt, most suited for cultivation of orange.
  • Winters are cold and dry without any rain and summers with heavy rainfall.
  • The other crops are the maize, paddy, oilseeds, pulses, large cardamom, ginger and vegetables etc.

 

  1. Low hill type:
  • The climate between 300 to 880 metres above the mean sea level may be called low hill type.
  • This climate is essentially a sub-tropical type and suitable for cultivation of sub-tropical fruits such as banana, guava, lemon and lime etc.
  • Most of the area is under paddy cultivation. Other important crops are maize, pulses, oilseeds, ginger and vegetables.
  • The winters are dry and comparatively warm and the summer are hot and have comparatively less rainfall.
  • Thus the Climate of Sikkim and the seasons of Sikkim state are suitable for growing varieties of crops which include not only cereals but also commercial crops.
  • Paddy, maize, millets, pulses are the principal crops and large cardamom, potato, ginger and other horticultural crops are the cash crops.
  • Orange is also a commercial fruits of Sikkim