Aspects Of Himalayan Hemlock Regeneration Ecology

Synopsis

Regeneration ecology of Himalayan Hemlock (Tsugadumosa) dominated conifer forests in Bhutan is littleunderstood and poses silvicultural challenges. Small-seeded hemlock and East Himalayan Spruce (Piceaspinulosa) are restricted to decomposed nurse logsand moss pads. Both species avoid other forest floormicrosites, especially bamboo litter. Larger-seededHimalayan Silver Fir (Abies densa) and Blue Pine(Pinus wallichiana) are able to regenerate on a widerrange of substrates, but not on bamboo litter. Undercompetition by the palatable bamboo Yushaniamicrophylla in gaps, cattle grazing facilitatesconifer regeneration, likely through increased lighton the ground and the availability of suitablesubstrates. Large silvicultural openings do notsupport high tree seedling densities, where shadingby understory vegetation facilitates hemlockregeneration. Smaller openings should be created tomaintain microclimatic conditions necessary formosses and large size logs and snags should beretained as nurse logs for regeneration of hemlockand spruce. In openings dominated by palatablebamboos, vegetation should be managed throughmoderate cattle grazing.