Species composition and community structure of forest stands in ...

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172 FOREST STRUCTURE IN KUMAON HIMALAYA Results Tree species classification Nineteen broad communities have been recognised in Kumaon. Overall, 63 tree, 56 shrub, 90 herb and 21 grass species were recorded in the 23 forest stands. A total of five homogenous groups of tree species, in relation to the environmental variables, was identified through TWINSPAN analysis (Fig. 2). The left arm of the first dichotomy contained 25 species, which was further divided into two groups. First negative group consisted of four species which were characteristic of site 8 (for site code see Fig 1). Second positive group also consisted of two homogenous groups. The first group contained Quercus semecarpifolia as a dominant species at sites 12, 13 and 17. The second group consisted of Abies pindrow and Taxus baccata as dominant species and represented mixed coniferous habitat. Further subdivisions did not provide any additional ecological information. The right arm of the first dichotomy had 38 tree species, which were further divided into two groups. First negative group contained 21 species. These tree species were mainly encountered at sites 2, 4, 5, 7, 18, 19 and 23. At site 2, Q. leucotricophora, Pinus wallichiana and Cedrus deodara were the dominant tree species while at site 23 the dominant species was Q. lanuginosa (Table 2). Tree species ordination DCA ordination successfully handled the variation in tree species communities from low to high altitude. All the sites and tree species showed meaningful distribution on axis 1 and axis 2 of DCA (Fig. 3 a). The first axis (eigen value = 0.389) represents an altitude gradient (low to high). Sites 14, 15, 16, 20, 21, and 22 occupied extreme end of the first axis and represented TWINSPAN group 3 (A. pindrow, T. baccata, Betula utilis, Tsuga Table 2. Communities and their characteristic tree species with their codes (in parentheses used in DECORANA computer program) in Kumaon based on TWINSPAN classification. Comm. = Community. Groups Comm. Forest stand Tree species 1 1 BWS Acer caesium (20), Aesculus indica (23), Swida sp.(42), Betula alnoides (44) 2 2 Daphiadura Gasi, Quercus semecarpifolia (4), Toona serrata (14), Dodecademia grandiflora (37), Dhakuri Symplocos sp. (50) 3 3, 4, 5, 6 Pindari, Sobala, Duku Wachham, Sunderdunga, Munsiary 4 7, 8, 9, 10, 11, 12, 13 Vinaiyak, Maheshkhan, Gager, Jilling, Majtham, Gandhura, Mechh 5 14, 15, 16, 17, 18, 19 Mukteshwer, Kilbery, Pandavkholi, Sitlakhet, Jageshwer, Kunjakharak Abies pindrow (15), Jugulans regia (34), Prunus cerasoides (63), Betula utilis (28) Rhododendron barbatum (7), Taxus baccata (16), Tsuga demosa (35), Pyrus vestita (52), Zanthoxylum armatum (58), Ficus palmata (46), Morus serrata (47), Symplocos chinensis (51), Prunus cornuta (60), Debregeasia hypoleuca (59), Acer cappadocicum (53), Fraxinus sp. (48), Dendroephthoe falcate (43) Cedrus deodara (17), Cupressus torulosa (25), Cassia fistula (62), Quercus lanuginose (5), Engelhardia spicata (36), Ficus auriculata (41), Daphnephyllum himalense (38), Quercus glauca (3), Pinus roxburghii (19), Myrica esculenta (24), Maytenus rufa (54), Benthamidia capitata (39), Phoenix humilis (61), Castanopsis tribuloides (40), Quercus leucotricophora (1), Pyrus pashia (13), Pinus wallichiana (18), Euonymus tingens (10), Swida oblonga (27), Macaranga pustulata (33), Picea smithiana (45) Litsea umbrosa (30), Populus ciliate (49), Persea duthiei (9), Rhododendron arboreum (6), Alnus nepalensis (21), Viburnum mullaha (22), Ilex dipyrena (26), Stranvissia nausea (57), Meliosma dillenaeafolia (29), Rhamnus triqueter (56), Quercus floribunda (2), Fraxinus micrantha (32), Symplocos theifolia (12), Lindera pulcherrima (31), Lyonia ovalifolia (8), Euonymus pendulus (11), Viburnum coriacieum (55)
demosa etc.), while the low altitude sites 4, 10, 18 and 23 represented TWINSPAN groups 4 & 5 (P. roxburghii, Q. leucotricophora, Pyrus pashia, Q. floribunda). The second axis (eigen value = 0.254) appeared to reflect the canopy cover from open to close. The species associated with open canopy were Q. glauca, Q. lanuginosa, Cassia fistula, Zanthoxylum armatum, Q. semecarpifolia and the representative sites were 13, 14, 18, 19 and 23, while close canopy areas were Gasi, Sobala, Duku (a) (c) HUSSAIN et al. 173 and Pandavkholi and the associated tree species were Q. semecarpifolia, Toona serrata, Symplocos theifolia (Fig. 3 b). These interpretations are largely confirmed by the results of PCA. The PC 1 explained 44.26% variance and represented a gradient of open to close canopy forest with tree density and diversity in increasing order. PC 2 explained 18.26% of variance and reflected an increasing pattern in shrub density and diversity. The distribution of species and sites was same on the two axes of PCA as on DCA axes (Fig. 3 c). Fig 3. (a) DCA ordination of tree species of Kumaon Himalaya on two axes extracted by DECORANA computer program. Numbers refer to different species, (b) DCA ordination of 23 surveyed forest stands on two axes. DCA axis 1 is related to altitude and slope. DCA axis 2 is related to canopy cover. Numbers refer to different sites, and (c) PCA ordination of surveyed forest stands on two extracted components. PC 1 is related to canopy cover and diversity of trees. PC 2 is related to the abundance of grasses and shrubs. Numbers refer to various sites. (b)
Page 1 and 2: HUSSAIN et al. 167 Tropical Ecology
Page 3 and 4: estimation of density, species dive
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Page 9 and 10: communities formed in the left arme
Page 11 and 12: deodara (0.17) were found to be rar
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Page 15: Whittaker, R.H. & H.G. Jr. Gauch. 1

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