Aspects of Himalayan Hemlock regeneration ecology

Regeneration ecology of Himalayan Hemlock (Tsuga§dumosa) dominated conifer forests in Bhutan is little§understood and poses silvicultural challenges. §Small-seeded hemlock and East Himalayan Spruce (Picea§spinulosa) are restricted to decomposed nurse logs§and moss pads. Both species avoid other forest floor§microsites, especially bamboo litter. Larger-seeded§Himalayan Silver Fir (Abies densa) and Blue Pine§(Pinus wallichiana) are able to regenerate on a wider§range of substrates, but not on bamboo litter. Under§competition by the palatable bamboo Yushania§microphylla in gaps, cattle grazing facilitates§conifer regeneration, likely through increased light§on the ground and the availability of suitable§substrates. Large silvicultural openings do not§support high tree seedling densities, where shading§by understory vegetation facilitates hemlock§regeneration. Smaller openings should be created to§maintain microclimatic conditions necessary for§mosses and large size logs and snags should be§retained as nurse logs for regeneration of hemlock§and spruce. In openings dominated by palatable§bamboos, vegetation should be managed through§moderate cattle grazing.