Composition of herbage in Pinus roxburghii Sargent stands: basal area and importance value index

In the present study basal area and Importance Value Index (IVI) attributes of herbage were investigated in chir pine (Pinus roxburghii Sargent) stands of three different ages and also in open grassland in the sub-tropical region of Himachal Pradesh (India) during growing season (June to September). A higher basal area of the herbage was recorded in open grassland as compared to chir pine stands of different ages. Basal area of the vegetation increased gradually from July onwards and its highest values were recorded in September in all the systems. Amongst the chir pine stands basal area of herbage was recorded highest in tree stand followed by pole and sapling stands. IVI and basal area values of different species revealed that only few species were major contributors to the total basal area values of the vegetation at different times. The differences in the basal area of vegetation in the four systems at a particular time and changes as recorded in the basal area with the sampling time were found to be statistically significant.   REFERENCES  Anderson, R.C. (۱۹۶۵) Light and precipitation in relation to pine understory development. MSc. Dissertation, University of Wisconsin, Madison, Wisconsin, ۵۱ p. Anderson, R.C., Loucks, O.L. & Swain, A.M. (۱۹۶۹) Herbaceous response to canopy cover, light intensity and throughfall precipitation in coniferous forests. Ecology, ۵۰, ۲۵۵-۲۶۳. Chaturvedi, O.P., Saxena, A.K. & Singh, J.S. (۱۹۸۸) Structural and functional analysis of grassland under pine forest in central Himalayas. Acta Ecologica, ۹, ۱۶۷-۱۶۸. Dalai, D. (۱۹۹۶) Productivity of grasses in relation to site quality in Pinus roxburghii Sargent plantations. MSc. Dissertation, Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.), India. ۷۴ p. Dass, B. (۱۹۹۵) System behaviour under Pinus roxburhii Sargent in Solan District (HP), MSc. Dissertation, Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan (HP), India, ۹۴ p. Dutt, V. (۱۹۹۹) Production of understory vegetation in relation to LAI and solar interception under chirpine. MSc. Dissertation, Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.), India, ۱۲۲ p. Federer, C.A. & Tanner, C.B. (۱۹۶۶) Spectral distribution of light in the forest. Ecology, ۴۷, ۵۵۱-۵۶۱. Grouzis, M. & Akpo, L.E. (۱۹۸۸) Influence of tree cover on herbaceous above- and belowground phytomass in the Sahelian zone of Senegal. J. of Arid-Environments. ۳۵(۲), ۲۸۵-۲۹۶. Guevara, S., Meave, J., Mareno, C. & Labrode, J. (۱۹۹۲) Floristic composition and structure of vegetation under isolated trees in neotropical pastures. J. of vegetation science. ۳, ۶۵۵-۶۶۴. Guleria, V., NayitaL, R.K. & Gupta, B. (۱۹۹۹) Biomass dynamics of grasses under Pinus roxburghii Sargent trees growing at different aspects. Range Mgmt. & Agroforestry. ۲۰, ۲۰۸-۲۱۱. Gupta, B. (۱۹۸۷) Structure, net primary productivity and nutrient cycling in grazed and ungrazed grassland ecosystem at Shardaghat, Shimla, PhD Dissertation, H P University, Shimla, India, ۵۷۵ p. Gupta, B., Chauhan, P.S. & Dass, B. (۲۰۰۰) Composition of herbage in Pinus roxburghii Sargent stands: species diversity and density. Journal of Tropical Forest Science. ۱۲, ۴۴۴-۴۴۹. Kapoor, K.S. (۱۹۸۷) Species composition, plant biomass and primary production in certain grassland ecosystems of Shimla hills. PhD Dissertation. H P University, Shimla, India. Lee, I.K. & Monsi, M. (۱۹۶۳) Ecological studies on Pinus densiflora forest. Effect of plant substances in the floristic composition of undergrowth. Botanical Management. ۷۶, ۴۱۰-۴۱۳. Melkania, N.P. & Tondon, J.P. (۱۹۸۳) Grass cover and their biomass as influenced by protection in Western Temperate Himalayas. Forage Research. ۹, ۶۱-۶۵. Misra, R. (۱۹۶۸) Ecology workbook. Oxford IBH publishing Co. Calcutta, India. pp. ۲۴۴. Phillips, E.A. (۱۹۵۹) Methods of vegetation study. A Holtdryden book. Henry Holt & Co. Inc. Sajwan, S.S., Singh, K., Agnihotri, Y. & Misra, P.R. (۱۹۸۰) Forage yield in different habitats on the plateau of low Ambala Shiwaliks. Indian Forester, ۱۰۶, ۷۸۶-۷۹۰.  Singh, J.S. & Yadava, P.S. (۱۹۷۴) Seasonal variation in composition, plant biomass and net primary productivity of a tropical grassland at Kurukshetra, India. Ecological Monograph. ۴۴, ۳۵۱-۳۷۶. Singh, K.S. & Lal, P. (۱۹۶۹) Effect of Khejri (Prosopis spp Linn) and Babool (Acacia arabica) trees on soil fertility and profile characteristics. Ann. Arid Zone. ۸, ۳۳-۳۶. Singh, R.P., Gupta, M.K. & Mathur, H.N. (۱۹۸۵) Effect of Pinus roxburghii plantations on the yield and composition of grasses in temperate region. Indian Forester. ۱۱۱, ۷۸۷-۷۹۳. Trivedi, B.K. (۱۹۹۴) Seasonal changes in composition of grassland communities in district of Jhansi. Range Management and Agroforestry. ۱۵, ۱۲۳-۱۲۹.

کلیدواژه ها:

Chir pine ، Grasses ، Sedges ، Legumes ، non ، Basal area ، Stands