BHARDWAJ, D.R.BANDANA, DEVI2017-02-142017-02-14201147625http://krishikosh.egranth.ac.in/handle/1/5810000763ABSTRACT The present investigations entitled “Biomass and carbon density under natural and plantation ecosystems in mid-hill sub-humid conditions of Himachal Pradesh” were carried out through independent experiments at different sites in and nearby vicinity of Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan located at 30o 50 30 to 30o 52 0 N latitude and the longitude 77o 8 30 and 77o 11 30 E in Himachal Pradesh lying at an elevation of about 900- 1300 a.m.s.l. The area falls under Champion and Seth’s forest type 9 C1 – Lower Himalayan Chir Pine Forests. The present investigations were conducted to assess the biological yield and carbon density under plantation and natural forest ecosystems. For conducting the experiment under natural forest ecosystem different forest vegetation were selected as treatments, which were; ban oak forest, chir pine forest, oak and pine forest, broad leaved forest, khair forest, scrub and grassland. Whereas, for conducting experiment under plantation ecosystem, different plantations were selected as treatments, which included; Quercus leucotrichophora, Pinus roxburghii, Acacia catechu, Acacia mollissima, Albizia procera, Alnus nitida, Eucalyptus tereticornis and Ulmus villosa plantation. Biomass allocated by different vegetation type was estimated using non-destructive method of sampling. The results of the experiment in natural forest ecosystem have revealed that maximum biomass (214.9 t ha-1) was accumulated in the chir pine forest, whereas, the maximum biomass in plantation (236.75 t ha-1) was recorded in Albizia procera plantation. Vegetation carbon density of natural forest ecosystem followed the order; chir pine forest > mixed broad leaved forest > oak and pine forest > ban oak forest > khair forest > scrub >grassland respectively in descending order. Whereas, in plantation ecosystem the order was; Albizia procera > Ulmus villosa > Eucalyptus tereticornis > Alnus nitida > Quercus leucotrichophora > Pinus roxburghii > Acacia mollissima > Acacia catechu. Similar trends were also seen in respect of biomass carbon stock of different vegetation types. Maximum soil carbon (humus + soil 0-100 cm layer) density under natural forest ecosystem was accumulated maximum (238.53 t ha-1) in khair forest, whereas in plantation ecosystem maximum (219.86 t ha-1) was recorded under Alnus nitida plantation. Total soil carbon density under natural forest ecosystem followed the trend; khair forest > ban oak forest > oak and pine forest > scrub > chir pine forest > mixed broadleaved forest > grassland ecosystem, respectively in descending order. In plantation ecosystem the soil carbon density did not varied significantly among plantation species. In natural forest ecosystem maximum quantity of total detritus carbon density was recorded (12.24 t ha-1) in mixed broad leaved, whereas, in case of plantation ecosystem maximum total detritus carbon density was recorded (6.79 t ha-1) in Pinus roxburghii plantations. Maximum carbon storage in the natural forest ecosystem (325.56 t ha-1), which is sum of vegetation + soil + detritus carbon pool was recorded in chir pine forest, which was followed by oak and pine forest, mixed broad leaved forest, ban oak forest, khair forest, scrub, grassland ecosystems respectively in descending order. Whereas, in plantation ecosystem maximum ecosystem carbon density (330.07 t ha-1) was displayed by Ulmus villosa, which is followed by Alnus nitida, Albizia procera, Acacia mollissima, Eucalyptus tereticornis, Quercus leucotrichophora, Pinus roxburghii and Acacia catechu respectively in descending order. Soil physico-chemical analysis revealed that there is significant variation due to nature of forest/species for bulk density, organic carbon, available nitrogen, EC and pH in different soil layers and humus layer. In humus and soil layers (0-20, 20-40, 40-100cm) under natural forest ecosystem, higher organic carbon, available nitrogen, were recorded, whereas plantation ecosystem displayed higher values for bulk density and pH . Whereas EC remained almost same in both the systems, but decreases with depthensowing, intercropping, wheats, tillage equipment, seed drilling, crops, mustard, fertilizers, land resources, chickpeasThesis