SHARMA, D.P.NARENDER, KUMAR2016-12-272016-12-27201648433http://krishikosh.egranth.ac.in/handle/1/93140ABSTRACT The present investigation entitled “Studies on growth performance and plant biodiversity status of deodar (Cedrus deodara) plantations along altitudinal gradient in Rajgarh forest division” was carried out in Sirmour district of Himachal Pradesh during the year 2014-15 with the aim to assess growth performance, soil physico-chemical properties and understory plant diversity of deodar plantation. Three elevations were selected viz., 1500-1800 m, 1800-2100 m, 2100-2400 m in northern and southern aspect. In each elevation 3 different sites were selected and 1 quadrat of 25m x 40m (0.1 ha) size was randomly laid to study tree species and composite soil samples were taken from each quadrat to study the soil physico chemical properties. The tree species includes all the saplings, poles and trees present in the study area. The shrub and herbaceous species were studied by laying 3 quadrats randomly in each elevation and aspect. In each quadrat, a sub-quadrat of 5m x 5m (25 sq m) size for shrubs and a sub-quadrat of 1m x 1m (1 sq m) for herbaceous vegetation were selected. The highest (786.56) numbers of trees were observed in the northern aspect at 1800-2100m elevation while lowest (536.67) were present in southern aspect. The diameter, height, basal area, volume, biomass, and carbon increment were observed highest at 1800-2100 m elevation in northern aspect as: 0.333 cm, 0.277 m, 0.350 m2 ha-1, 3.638 m3 ha-1, 1695.55 kg ha-1 and 847.78 kg ha-1 respectively. While lowest values were observed in the southern aspect. The soil nutrients like available nitrogen, phosphorus, potassium, organic carbon, soil moisture and soil humus depth were found in the range as: 253.88-511.18 kg ha-1, 9.27-24.75 kg ha-1, 167.25-285.14 kg ha-1, 1.33-2.55 %, 20.32-39.74 % and 0.63-1.40 cm respectively. Soil available nitrogen, phosphorus, organic carbon, soil moisture and soil humus depth were found higher in northern aspect while potassium was found highest in southern aspect. In plant diversity the shrubs density, abundance and percent frequency were found highest in northern aspect at lower elevation, and lowest in southern aspect at upper elevation. While basal area was found highest in southern aspect. In herbaceous vegetation the density and abundance were found highest in southern aspect at 1800-2100 m elevation, while basal area and percent frequency were found highest in northern aspect at 1500-1800 m and 1800-2100 m elevation respectively. The similarity index of both herbs and shrubs increased with the increase in elevation. The shrubs diversity, dominance and richness were highest in northern aspect at middle elevation. The herbs diversity was found highest in northern aspect and dominance and richness were highest in southern aspect.enThesis