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.

Autorentext

Dr. András Darabant studied forestry at BOKU University Vienna,Austria and currently works on a research partnership dealing withforests and sustainable land use in Bhutan.

Klappentext

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.