Upper Gangetic Plains Moist Deciduous Forest

Most of the original deciduous forest of the Upper Gangetic Plain was probably dominated by Shorea robusta (sal). It forms an upper canopy tree reaching heights of up the 35 m. Other commonly associated trees would have included Adina cordifolia, Dillenia pentagyna, Lagerstroemia parviflora, Stereospermum suaveolens, Terminalia belerica and T. tomentosa. However, today only one large continuous stand remains. It extends along the Himalayan foothills of Utter Pradesh and includes the Corbett, Dudwa and Rajaji national parks. In the Siwali Hills, where the Corbett National Park has been established, canopy trees other than the ones mentioned above include Anogeissus latifolia, Diospyros tomentosa, Garuga pinnata, Lannea coromandelica and Pinus roxburghii. Common second story species are Buchanania lanzan, Dendrocalamus strictus, Ehretia laevis, Ougeinia oojeinensis and Semecarpus anacardium, while typical third story species include Berberis asiatica, Clerodendron viscosus, Colebrookea oppositifolia, Indigofera cassioides, Murraya koenigii, Pogostemon plectranthoides and Woodfordia fruticosa. Common shrub layer species are Chrysopogon fulvus, Heteropogon contortus and Thysanolaena maximus, while typical herbs include Bauhinia vahlii and Milletia auriculata. However, the physiognomy of these forests depends on various factors particularly relating to variations in local climate, topography, geology and soil. In the hilly areas, sal is often stunted while in dry areas it is usually confined to the cooler more moist depressions. In the outer Himalayas it can ascend to altitudes of about 1500 m, but the best sal forests occur at low altitudes on deep loamy soil.

 

Upper Gangetic Plains Tropical Moist Deciduous Riverine Forest

These forests occur on recent alluvium plains throughout much of the moist part of the Gangetic Plain but are particularly prevalent in the sub-Himalayan zones of Uttar Pradesh and Bidar. These riverine areas are usually well drained but liable to erosion and flooding and much of the well-established forest occurs on the higher more stable alluvial terraces. The upper story typically includes Adina cordifolia, Bombax ceiba, Garuga pinnata, Gmelina arborea, Hymenodictyon excelsum, Lagerstroemia parviflora, Lannea coromandelica and Terminalia belerica. A few climbers and bamboos occur locally. Common second storey species are Cassia fistula, Dendrocalamus strictus, Ehretia acuminata, Emblica officinalis, Holarrhena anti-dysenterica, Mallotus philippensis, Randia longispina and Zizyphus mauritiana. However, the trees in these forests rarely form extensive stands and many of the constituent species develop in small gregarious groups, but there is usually a well-developed shrub layer. Typical shrubs include Adhatoda vasica, Callicarpa macropylla, Glycosmis cochinchinensis, Helicteres isora, Murraya koenigii and Podostemon plectranthoides. In places the shrub layer is so dense that few ground layer species can exist and grasses are often sparse or absent. Ground layer species that may be present include Oryptolepis buchanani and Vallaris heynei.

 

Upper Gangetic Plains Sporobolus-Chloris Saline Scrub

In parts of the Gangetic Plain the soils have high concentration of salts. These occur in areas where there is restricted drainage combined with high summer temperatures and low monsoonal rainfall. The vegetation has an irregular, semi-savannah appearance with Acacia arabica dominating the loamy soils and Butea frondosa the clayed waterlogged areas. Azadirachta indica is also frequent and the palm Phoenix sylvestris has a scattered distribution. At ground level the gregarious, perennial grass Sporobolus pallidus often dominates together with the annual grass Chloris montana and the annual forb Cyanotis axillaris. However, many of the characteristic species have sporadic distributions. These include, for example, Aeschynomene indica, Alysicarpus bupleurifolius, Aneilema nudiflorum, Corchorus acutangularis, Cyperus aristatus, Oldenlandia diffusa, Portulacea oleracea, P. tuberosa and the grasses Aristita hystrix, Desmostachya bipinnata and Paspalidium flavidum. In hollows and shallow depressions where rainwater can accumulates “wild paddies” often develop characterized by species such as Echinochloa colonum, Ischaemum rugosum and Paspalum scrobiculatum.

 

Upper Gangetic Plains Phragmites-Saccharum-Imperata Grassland

These grasslands extend throughout the Gangetic Plain and also on to the plains of Punjab and into the Brahmaputra Valley. They are characteristic of low-lying, poorly drained land with high water tables. The typical perennial grasses are Imperata cylindrica, Phragmites karka and species of Saccharum (including S. arundinaceum, S. bengalense and S. spontaneum), but other perennial grasses represented throughout the distribution of this formation include Bothriochloa intermedia, B. odorata, Chrysopogon aciculatus, Cynodon dactylon, Desmostachya bipinnata, Hymenachne pseudointerrupta, Ischaemum timorense, Narenga porphyrocoma, Neyraudia reynaudiana, Panicum notatum, Paspalum conjugatum, Sclerostachya fusca, Sporobolus indicus and Vetiveria zizanoides. Typical annual species are Aluda mutica, Chionachne koenigii, Dactyloctenium aegyptium, Echinochloa colonum, Eragrostis viscosa, Ischaemum rugosum, Microstegium ciliatum, Paspalum scrobiculatum and Schizachyrium brevifolium. In addition to grasses well over 50 species of herbaceous forbs have also been recorded. These include Alysicarpus monilifer, Blumea membranacea, Euphorbia hirta, Hyptis brevipes, Killinga brevifolia, Leucas aspera, Lindernia crustacea, Lochnera rosea and Mikania scandens. However, in very swampy areas the reed Phragmites karka can become almost monodominant covering up to 90% of the areas.

Further information required.

 

References

Dabadghao, P. M. & Shankarnarayan, K. A. 1973. The Grass Cover of India. Indian Council of Agricultural Research, New Delhi.

Duthie, J. F. 1973a. Flora of the Upper Gangetic Plain. Volume. 1. Ranunculaceae to Cornaceae. Bishen Singh Mahendra Pal Singh.

Duthie, J. F. 1973b. Flora of the Upper Gangetic Plain. Volume. 1. Plumbaginaceae to Juncaceae. Bishen Singh Mahendra Pal Singh.

Khanna, K. K., Mudgal, V., Ubiyal, B. P. & Sharma, J. R. 1999. Dicotyledonous Plants of Uttar Pradesh. Bishen Singh Mahendra Pal Singh, Dehra Dun, India.

Misra, R. 1959. The status of the plant communities in the Upper Gangetic Plain. The Journal of Indian Botanical Society. XXXVIII: 1-7.

Puri, G. S., Gupta, R. K., Meher-Homji, V. M. & Puri, S. 1989. Forest Ecology. Plant form, diversity, communities and succession. 2nd Edition. Volume 2. Oxford & IBH Publishing Co. PVT. Ltd.

Raizada, M. B. 1954. Grasses of the Upper Gangetic Plain and some aspects of their ecology. Indian Forester, 80: 24-46.

Seth, S. K. 1954. The principal grassland types and other grass habitats of Utter Pradesh. Bulletin U. P. Forest Department, 24: 1-28.