CHAPTER 4 VEGETATION

Transcription

1 CHAPTER 4 VEGETATION

2 Vegetation of Kinnaur district is influenced by altitudinal ranges, climate and more significantly by the soil texture and rainfall. Very scanty rainfall, extreme fluctuations of temperature and soil texture are some of the factors which effect the vegetation of study area. Construction of Hydroelectric power projects and roads, clearing of forests for agricultural and horticultural purposes, over-exploitation for medicinal plants and grazing by domestic animals are responsible for the degradation of vegetation of the area. The vegetation is not compact, and the number of species decreases as one moves towards high cold arid regions due to harsh climatic conditions. Usually, the lower parts of Kinnaur are much greener than upper parts of Kinnaur where climate is much drier. The lower parts of Kinnaur district between the altitudes of m in the Kalpa Valley, Sangla Valley, Bhabha Valley, Ropa Valley, Ganjul Valley, Tidong Valley and lower parts of Sutlej Valley are covered by a thick blanket of natural forests where the vegetation is of dry temperate to moist temperate type (Figs. 36, 37). Whereas the upper arid Trans Himalayan region covering the valleys of Ganjul, Ropa, Tidong, Hangrang, and Sutlej which is characterized by barren, rocky and naked mountains, the vegetation is of sub alpine to alpine type. Interacting biophysical (elevation, soil types, moisture, flooding slopes), climatic and anthropogenic factors (burning, agriculture, fuelwood collection, hunting, non-timber forest product gathering) have resulted in the development of a mosaic of forests and vegetation types in this zone. The vegetation of the district can be broadly classified into three types:- 4.1 Temperate ( m) 4.2 Sub-alpine ( m) 4.3 Alpine (>3500m) 4.1 TEMPERATE VEGETATION Himalayan Moist Temperate Forests These forests fall in the areas of Sutlej Valley between Chaura (1890m) to Nichar (2150m) and Chaura (1890m) to Nathpa (1680m); Bhabha Valley ( m); Kalpa Valley ( m) and Sangla Valley ( m). 21

3 These forests are further categorized into Lower and Upper Western Himalayan Temperate forests a Lower Western Himalayan Temperate Forests Ban Oak Forests These forests are growing in Nichar region (2150m) of Sutlej Valley dominated by trees of Ban oak (Quercus leucotrichophora A. Camus) associated with some trees of Rhododendron arboreum Smith, Lyonia ovalifolia (Wall.) Drude, Machilus odoratissima (Wall. ex Nees) Nees, Litsea umbrosa (Nees) Nees, Myrica sapida Wall., Symplocos crataegoides Buch.- Ham. ex D. Don and Benthamidia capitata (Wall.) H. Hara. Pinus roxburghii Sarg., P. wallichiana A. B. Jackson and Cedrus deodara (Roxb.) G. Don are the conifers which are occasionally present. Moru Oak Forests Moru oak (Quercus floribunda Lindl. ex A. Camus) forests which are also found at similar altitudes in the Sutlej Valley have Q. semecarpifolia Smith, Q. leucotrichophora A. Camus, Betula alnoides Buch.-Ham. ex D. Don and Carpinus viminea Wall. as the common associates. Moist Deodar Forests Pure deodar (Cedrus deodara (Roxb.) G. Don) forests recorded in the Sutlej Valley ( m) (Fig. 38) have occasional occurrence of trees of Pinus wallichiana A. B. Jackson and Q. leucotrichophora A. Camus. Rosa macrophylla Lindl., Berberis lyceum Royle, Lonicera angustifolia Wall. ex Candolle, Strobilanthes wallichii Nees, Deutzia staminea R. Br. ex Wall. and Jasminum officinale L. are the frequently occurring shrubs. Clematis montana Buch.-Ham. ex DC., Vitis himalayana Brandis and Hedera nepalensis K. Koch are the common climbers. Western Mixed Coniferous Forests The areas falling in the Sutlej Valley and Kalpa Valley (Fig. 39) between altitudes of m have a varying mixture of tall coniferous trees of spruce (Picea smithiana (Wall.) Boiss.), fir (Abies pindrow (Royle ex D. Don) Royle) and deodar (Cedrus deodara (Roxb.) G. Don.) are commonly associated with chilgoza (Pinus gerardiana Wall. ex D. Don), blue pine (Pinus wallichiana A. B. Jackson), chir (Pinus roxburghii Sarg.) and oaks (Quercus floribunda Lindl. ex A. Camus, Q. leucotrichophora A. Camus, Q. semecarpifolia Smith). Species of Fragaria, Viola, Pteridium and Adiantum constitute the herbaceous elements. 22

4 4.1.1b Upper Western Himalayan Temperate Forests West Himalayan Upper Oak-Fir Forests Between the altitudes of m, the Sutlej Valley and Sangla Valley are dominated by forests of Abies pindrow (Royle ex D. Don) Royle and Quercus semecarpifolia Smith associated with some trees of Betula alnoides Buch.-Ham. ex D. Don, B. utilis D. Don and Sorbus foliolosa (Wall.) Spach. Spiraea bella Sims, Cotoneaster acuminata Lindl., Rhododendron campanulatum D. Don, Viburnum nervosum D. Don, Spiraea sp. and Strobilanthes sp. constitute the shrubby elements. Fragaria vesca L. and species of Senecio, Stellaria and Nepeta constitute the herbaceous flora Himalayan Dry Temperate Forests At altitude of m in Chini (2440m), Kilba (2480m) and Purbani regions (2960m) of Kalpa Valley, Tidong Valley up to Thangi (2700m), Ganjul Valley up to Pooh (2840m), Ropa Valley up to Ropa (3000m), Sangla Valley up to Chittkul (3450m) and parts of Bhabha Valley ( m), vegetation is of dry temperate type with predominating conifers Cedrus deodara (Roxb.) G. Don, Pinus gerardiana Wall. ex D. Don and Juniperus spp. Trees of fir (Abies spectabilis (D. Don) Spach) and blue pine (Pinus wallichiana A. B. Jackson) are present at higher elevations. Among the broad leaved trees, species of Acer, Fraxinus and Quercus are important constituents. In dry regions between Moorang (2590m) to Thangi (2700m) of Tidong Valley and in Pooh (2840m) region of Ganjul Valley, Colutea nepalensis Sims is the most typical shrubby species. Broadly four main types of dry temperate forests found in the area are: 4.1.2a Dry Broadleaved and Coniferous Forests These forests are found in Kilba region (2480m) of Kalpa Valley having dominant species of Pinus gerardiana Wall. ex D. Don and Quercus ilex L., occasionally associated with trees of Cedrus deodara (Roxb.) G. Don, Acer pentapomicum Stewart ex Brandis and Celtis australis L. Fraxinus xanthoxyloides (G. Don) DC., Rhus succedana L., Parrotia jacquemontiana Decne., Olea cuspidata Wall., and Zanthoxylum alatum Roxb. are the small sized tree species. Artemisia maritima L., A. vulgaris L., Daphne oleoides Schreb., Plectranthus rugosus Wall., Rosa 23

5 webbiana Wall. ex Royle, Roylea calycina (Roxb.) Briq., Lonicera angustifolia Wall. ex Candolle and Berberis spp. form the shrubby elements. The grasses include Agropyron longearistatum (Boiss.) Boiss., Agrostis alba L., Eragrostis nigra Nees ex Steud., Perotis indica (L.) Kuntze, Phleum arenarium L., Setaria viridis (L.) Beauv., etc b Dry Temperate Coniferous Forests Neoza Pine Forests These are found in the Purbani region (2960m) of Kalpa Valley and Pangi region of Tidong Valley (2790m) having a pure forest of chilgoza (Pinus gerardiana Wall. ex D. Don) (Fig. 40), occasionally associated with trees of Cedrus deodara (Roxb.) G. Don (Fig. 41). Lonicera hypoleuca Decne., Artemisia maritima L., Daphae oleoides Schreb., Ephedra gerardiana Wall., Caragana gerardiana Royle ex Benth. and Prunus jacquemontii Hort. f. constitute the shrubby and herbaceous elements. Dry Deodar Forests Dry deodar forests are located in Kilba (2480m) and Chini (2440m) regions of Kalpa Valley and Pangi region (2790m) of Tidong Valley. Cedrus deodara (Roxb.) G. Don is the dominant species occasionally associated with Pinus gerardiana Wall. ex D. Don and Picea smithiana (Wall.) Boiss. Viburnum cotinifolium D. Don, Desmodium elegans DC., Lonicera quinquelocularis Hardw., L. hypoleuca Decne., Smilax vaginata Decne., Rosa webbiana Wall. ex Royle, Rubus niveus Thunb., Plectranthus rugosus Wall. and Berberis sp. form the shrubby elements. Fragaria vesca L., Viola canescens Wall. ex Royle, Thalictrum minus L., Salvia glutinosa L., and Impatiens spp., constitute the herbaceous vegetation c West Himalayan High Level Dry Blue Pine Forests The dry blue pine (Pinus wallichiana A. B. Jackson) forests are located at Chittkul (3450m) in Sangla Valley (Fig. 42). Blue pine trees are commonly associated with Pinus gerardiana Wall. ex D. Don, Abies spectabilis (D. Don) Spach, Betula utilis D. Don and Rhododendron campanulatum D. Don. Other common associates are Juniperus communis L., J. wallichiana Hook. f. et Thoms., J. macropoda Boiss., Rhododendron anthopogon D. Don and species of Caragana, Ephedra and Lonicera. 24

6 4.1.2d West Himalayan Dry Juniper Forests Areas between Moorang (2590m) to Thangi (2700m) in Tidong Valley, Sunnum (2680m) to Ropa (3000m) in Ropa Valley and parts of Bhabha Valley ( m) are dominated with Juniperus macropoda Boiss. (Fig. 43) along with shrubs of Fraxinus xanthoxyloides (G. Don) DC., Ephedra gerardiana Wall. (Fig. 44), and Rosa webbiana Wall. ex Royle. Hippophae-Myricaria scrub of dry temperate vegetation recorded at Sangla (2680m) in Sangla Valley have a dominance of Hippophae salicifolia D. Don, Salix viminalis L., Myricaria elegans Royle and M. germanica L. Besides these forest types, various plant communities which are commonly met at different places in the district are: Cedrus deodara-quercus ilex community It can be seen in the area of Kuppa and Ruturang at altitude of 2650m in Sangla Valley. Fraxinus xanthoxyloides (G. Don) DC. and Desmodium floribundum G. Don are the common shrubs. The herbaceous layer is scanty which is constituted by Artemisia nilagirica (Clarke) Pampanini, Plectranthus rugosus Wall. and species of Chenopodium, Fragaria, Nepeta, Potentilla and Salvia. Pinus gerardiana-quercus ilex community This type of plant community is located in the Sutlej Valley from Tapri (1680m) to Karchham (1900m). The shrubby elements consist of plants of Daphne oleoides Schreb., Olea cuspidata Wall. ex DC., Cynanchum roylei Wight and Desmodium floribundum G. Don. Cannabis sativa L., Plectranthus rugosus Wall. and species of Potentilla and Impatiens are also present Cedrus deodara-pinus gerardiana-quercus ilex community This is found at Kalpa (2760m) and Kilba (2480m) in Kalpa Valley. Chenopodium album L., Cannabis sativa L. and Rumex species are the most common. 4.2 SUB-ALPINE VEGETATION Between altitudes of m, in Ganjul Valley, Ropa Valley, upper parts of Sutlej Valley, Tidong Valley and Hangrang Valley, vegetation is of sub-alpine type. Various types of forests met in sub-alpine zone are: 25

7 4.2.1 West Himalayan Sub-alpine Fir Forests In these forests, Abies spectabilis (D. Don) Spach is most commonly associated with Pinus wallichiana A. B. Jackson and Juniperus wallichiana Hook. f. et Thoms. (Fig. 45). Rhododendron campanulatum D. Don, R. lepidotum Wall. ex D. Don and Berberis spp. are often present predominantly. Other genera widely represented in the forests include Anemone, Viburnum, Lonicera, Berberis, Polygonum, Viola and Salix Western Himalayan Birch/Fir Forests Betula utilis D. Don is the dominating and the largest deciduous tree associated with Abies spectabilis (D. Don) Spach and Pinus wallichiana A. B. Jackson. Cotoneaster acuminata Lindl., Rosa sericea Lindl., Smilax vaginata Decne. and Lonicera spp. constitute the shrubby elements Sub-alpine Pastures These pastures have predominating grasses which include Agropyron longearistatum (Boiss.) Boiss., A. semicostatum (Ness ex Steud.) Boiss., Brachypodium sylvaticum (Huds.) Beauv, Bromus asper Murray, B. japonicas Thunb., Milium effusum L., and species of Dactylis, Danthonia, Festuca, Phleum and Poa. 4.3 ALPINE VEGETATION At higher altitudes between m in the upper parts of valleys of Sutlej, Ropa, Sangla, Ganjul, Tidong and Hangrang, the vegetation is very scanty and typically of alpine desert type with the dominance of junipers, pines, firs, cypers and rhododendrons. The alpine vegetation is further subdivided into three types: Alpine Forests These forests are the extension of the temperate forests and constituted by Betula utilis D. Don, associated with Pinus wallichiana A. B. Jackson, Rhododendron campanulatum D. Don and Sorbus foliolosa (Wall.) Spach. Lonicera parviflora C.B. Clarke and species of Cotoneaster, and Berberis constitute the shrubby flora. The herbaceous elements consist of species of Potentilla, Primula, Cardamine, Meconopsis, Corydalis, Polygonum, Allium, Trillium, etc. 26

8 4.3.2 Alpine Meadows The alpine meadows are long undulating grassy plains or pasture lands. At certain places these are replaced by glacial morains. The alpine meadows have Juniperus communis var. saxatilis Pall., J. squamata Buch.-Ham. ex D. Don and Rhododendron anthopogon D. Don. Plants like Elsholtzia strobilifera Benth., E. fruticosa (D. Don) Rehdr and Chenopodium album L. which are also common at lower elevations become stunted here. The herbaceous elements include Aconitum violaceum Jacq. ex Stapf, Anemone rivularis Buch.-Ham. ex DC. (Fig. 46), A. rupicola Camb., A. obtusiloba D. Don, A. polyanthes D. Don, Arabis tibetica Hook. f. et Thoms., Arnebia euchroma (Royle) Johnston, Astragalus webbianus Grah. ex Benth., Delphinium brunonianum Royle, Dracocephalum heterophallum Benth., Lagotis kunawurensis (Royle ex Benth.) Rupr., Picrorhiza kurroa Royle ex Benth., Swertia petiolata Royle ex D. Don, Thalictrum alpinum L., Lactuca macrorrhiza (Royle) Beauv, Phytolacca acinosa Roxb., Morina coulteriana Royle (Fig. 47), Achillea millefolium L., Androsace rotundifolia Hardw., Thymus linearis Benth. and species of Pedicularis, Polygonum, Potentilla, Primula, Ranunculus, Saxifraga and Bromus. Elymus nutans Griseb., Pennisetum lanatum Klotzsch, Phleum alpinum L., Poa alpine L. and P. tibetica Munro ex Stapf are the common grasses Alpine Scrubs Above tree line ( m), the vegetation is of scrub type, mainly found on ridges and on rocky slopes. These alpine scrubs are further categorized into two types, as moist alpine scrubs and dry alpine scrubs a Moist Alpine Scrubs Moist alpine scrubs are dominated by Rhododendron anthopogon D. Don, commonly associated with species of Cotoneaster, Corydalis, Astragalus, Potentilla, Sedum, Rhodiola, Rheum, Caltha, Cassiope, etc. Viburnum nervosum D. Don, Lonicera parviflora Lam. and Berberis spp. form the shrubby elements b Dry Alpine Scrubs In these scrubs, Juniperus is predominant along with Artemisia maritima L., and species of Draba, Meconopsis, Potentilla, Carex, Caragana, etc. Higher up the dry scrub alpine gives the place to stony 27

9 desert, where only few herbs such as Sedum crassipes Wall. ex Hook. f. et Thoms., Primula minutissima Jacquem. ex Duby, Saxifraga imbricata Royle and species of Arenaria, Potentilla and Androsace are present. In sub-alpine to alpine regions, the plant communities which are present include: Pasture community Many regions falling in the valleys of Sangla, Kalpa and Sutlej are subjected to shifting cultivation and pasture community develops. The common constituents of such communities are Anemone rivularis Buch.-Ham. ex DC., Achillea millefolium L., Brachyactis roylei (DC.) Aitch. & Clarke, Chaerophyllum acuminatum Lindl., Cichorium intybus L., Desmodium nutans Wall. ex Parker, Erigeron bonariensis L., Fagopyrum esculentum Moench, Fragaria nubicola (Hook.) Lindl. ex Lacaita, Galinsoga parviflora Cav., Lactuca dissecta D. Don, Medicago lupinia L., M. falcata L., Origanum vulgare L., Papaver dubium L., Plantago depressa Willd., Potentilla argyrophylla Wall. ex Lehm., P. nepalensis Hook., Taraxacum officinale F. H. Wigg., Thymus serpyllum L., etc. Secondary dry scrub community In places where Quercus forests have been destroyed due to construction of hydroelectric power projects and roads or clearing of forests for agricultural and horticultural purposes, the soil is shallow and substratum is mostly rocky. The scrub vegetation in such region include oak trees associated with Desmodium floridundum G. Don., Cotoneaster affinis Lindl., Withania somnifera Dunal, Plectranthus rugosus Wall., etc. Secondary moist scrub community The community has scattered trees of Salix elegans Wall. ex Anders, Prunus cornuta (Wall. ex Royle) Steud. and Morus serrata Roxb. Colebrookia oppositifolia Smith, Ajuga parviflora Benth., Clinopodium vulgare L., Persiearia nepalensis (Meissn.) H. Gross., Lecanthes peduncularis (Royle) Wedd., and species of Pedicularis, Anemone and Impatiens are the common associates. Besides these forest types, plant communities and vegetation types, some of the species are found in specific habitats like rock crevices, dry sandy 28

10 slopes and among stones; moist open and shaddy slopes; and along stream side, river or water channels in the study area (Figs ). The species commonly grow in rock crevices, dry sandy slopes and among stones are Ranunculus pulchellus C.A. Mey, Thalictrum foetidum L., Arabis tibetica Hook. f. et Thoms., Capparis spinosa L., Arenaria edgeworthiana Majumdar, Minuartia kashmirica (Edgew.) Mattfield, Astragalus chlorostachys Lindl., A. graveolens Buch.-Ham. ex Benth., A. rhizanthus Royle ex Benth., Chenopodium sp., Lotus corniculatus L., Potentilla bifurca L., P. cuneifolia Bertol., Heracleum candicans Wall. ex DC., Eriocycla caespitosa (Edgew.) H. Wolff, Trigonella emodi Benth., T. pubescens Edgew. ex Baker, Androsace sermentosa Wall., Dianthus angulatus Royle ex Benth., Campanula argyrotricha Wall. ex DC., Anaphalis virgata Thoms. ex C.B. Clarke, Crepis glauca Benth., C. sancta (L.) Babcock, Inula cappa DC., I. cuspidata C.B. Clarke, Senecio krascheninnicovi Schischk., Anaphalis sp., Jasminum sp., Viola sp., Polygala abyssinica R. Br. ex Fresen., Cynoglossum glochidiatum Wall., Leucas lanata Wall. ex Benth., Thymus linearis Benth., Incarvillea arguta (Royle) Royle, I. emodi Royle ex Lindl., Hippophae rhamnoides L., etc. Some of species which commonly grow on moist open and shaddy slopes are, Thalictrum minus L., Corydalis cornuta Royle, C. ramosa Wall., Arabis glabra Crantz, A. nova Vill., Impatiens sulcata Wall., I. thomsonii Hook. f., Silene edgeworthii Bocquet, Astragalus chlorostachys Lindl., Potentilla atrisanguinea Lodd. var. argyrophylla (Wall. ex Lehm.) Griers and Long., P. atrisanguinea Lodd. var. atrisanguinea, Senecio chrysanthemoides DC., S. graciliflorus DC., Androsace sermentosa Wall., Euphrasia himalayica Wettst., Pedicularis bicornuta Klotzsch and Rumex hastatus D. Don. Species which are found along stream side or water channels include Anemone tetrasepala Royle, Ranunculus laetus Wall. ex Royle, Berberis aristata DC., Saponaria vaccaria L., Impatiens scabrida DC., I. sulcata Wall., Melilotus alba Lamk., Trifolium repens L., Epilobium roseum Schreb., Sonchus asper Vill., S. oleraceus L., Veronica anagallis-aquatica L., Mentha longifolia (L.) Huds., Plectranthus coetsa Buch.-Ham. ex D. Don, Thymus linearis Benth., 29

11 Jasminum sp., Pteracanthus alatus (Wall. ex Nees) Bremek., Hippophae rhamnoides L., Dicliptera bupleuroides Nees, etc. Some tufted plants typical of cold deserts in the area include Arenaria festucoides Benth., Cerastium cerastioides (L.) Britton, Astragalus sp., Dianthus angulatus Royle ex Benth., Rosularia alpestris (Kar. & Kir.) A. Boiss., Lactuca orientalis (Boiss.) Boiss., Salsola sp., Silene stewartii (Edgew.) Maj., Senecio krascheninnicovi Schischk., etc. 30