During the present study, the distribution and phytosociological association of orchids with higher plants were determined. All the orchid species were noted down from each site with the association of the phorophytic plants. Altogether, 43 orchid species along with 52 tree species were recorded from all the six studied sites. The more number of species were presently observed in the Gurguria region followed by Chahala. Amongst these phorophytic plants, only 9 tree species were mostly associated with epiphytic orchids which gave shelter and shade to these plants. The girth class relations to the orchid species were monitored at each site; these revealed that GBH [Girth at Breast Height (61 cm - 150 cm)] were always preferable for orchids, because the dead cell mass and the dust particles along with some gum secreted by the phorophyte was always deposited on that and this might be the reason for growth of moss and epiphytic orchids on that girth class. The most favourable locality of the ground orchids was sandy soil along with high humidity. Furthermore, fragmentation of habitats, removal of key species critical to the continued existence of ecosystems, increased susceptibility to fire threats, pollinator decline, and introduction of feral animals were also documented to result in drastic losses in orchid populations and diversity. However, detailed information on orchid population and biology is needed to assist conservationists so as to develop an appropriate management strategies in highly fragmented and altered landscapes. Presently, the main approach was to find out the ecological stress related to girth class preference of phorophytes on orchid flora of Similipal Biosphere Reserve and their subsequent management, in future.