Sikkim yana cikin yanayin muhalli na ƙananan Himalayas, ɗaya daga cikin uku kawai a cikin ecoregions na Indiya. Yankunan da ke cikin gandun daji na jihar suna nuna nau'ikan fauna da tsire-tsire masu yawa. Saboda yanayin tsaunukansa, jihar tana da tsire-tsire iri-iri, daga nau'ikan wurare masu zafi zuwa matsakaici, tsaunuka da tundra, kuma wataƙila yana ɗaya daga cikin yankuna kalilan da ke nuna irin wannan bambancin a cikin irin wannan ƙaramin yanki. Kusan kashi 81 cikin ɗari na yankin Sikkim yana ƙarƙashin kulawar sashen gandun daji. Sikkim gida ne ga kusan nau'ikan tsire-tsire masu fure 5,000, 515 rare orchids, 60 primula, 36 rhododendron, 11 nau'in oak, 23 bambaro iri, 16 conifer, 36 nau'in nau'in mita mita mita da ferns, 8 ferns da ferns, da kuma ferns a sama da 5,000 ft. A cikin tsaunukan tsaunuka na gabas, jihar tana da nau'ikan tsire-tsire iri-iri
bambancin fauna da flora