Forest Structure and Regeneration of Quercus semecarpifolia in Api-Nampa Conservation Area, Nepal
Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Faculty of Botany
Abstract
Himalayan forest is dominated by different species of Oaks (Quercus spp.) at different
altitudes. This work was carried out to study the forest structure and regeneration of Q.
semecarpifolia along altitudinal gradient in Api-Nampa Conservation Area. The vegetation
data was collected from a total of 48 number of 20×20 m square quadrat for tree species in
which plots were established at lower limit of Q. semecarpifolia i.e. 2489 masl to uppermost
limit i.e 3636 masl. The Shrubs and tree saplings including lianas were recorded from the
nested plot sized by 25 m
2
and herbs and tree seedlings from the quadrat size of 4 m
2
.
Importance Value Index (IVI) of tree, shrub and herb species, distribution pattern of
seedlings and saplings, and soil attributes were analyzed. Regeneration was assessed by
density - diameter curve. Fourty-eight soil samples were taken for laboratory analysis. A total
of 188 species of woody and non-woody species belonging to 67 families were recorded.
Tree species richness in the forest decreased with increasing elevation. The most frequent and
dense tree species in the forest was Q. semecarpifolia with important value index percent of
about 19% (IVI=56) and it was present in 80% of the sampling plots. IP of Q. semecarpifolia
in the lower elevation range was 8% and in middle and upper range 17% and 41%
respectively. Seedling and sapling were present in 30.2% and 75% of sample plot in the
forest. The tree density of Q. semecarpifolia in the forest area was 235stem/ha with basal area
42.22 m
2
/hectare. Seedling and sapling density of Quercus semecarpifolia in the forest was
4010 stem/ha and 1058 stem/ha. All the tree, sapling and seedling density and basal area of
Q. semecarpifolia were higher in the higher elevations. The average maximum DBH of Q.
semecarpifolia was 46.72 cm and average maximum height was 18.61 m. Q. semecarpifolia
above 2800 m elevation showed sustainable regeneration as evident from reverse J shaped
curve. However it below 2800 m elevation showed weak regeneration as evident from bell
shaped curve. Altitude was the main factor for unequal distribution of species along the
altitude. Soil nutrient such as nitrogen and potassium showed positive but insignificant
relationship with seedlings and saplings.
Description
Keywords
Forest structure, Regeneration, Brown oak, Diversity index, Importance value index