Species composition and community structure of forest stands in ...

168 FOREST STRUCTURE IN KUMAON HIMALAYA
comunidades arbóreas e 17 comunidades de vegetação rasteira. A distribuição das espécies
arbóreas no eixo DCA indicam a covertura pelo copado e a diversidade dos arbustos. A primeira
componente do ACP representou florestas com copado aberto a fechado, enquanto a segunda
reflectiu o aumento na densidade e diversidade dos arbustos. O grupo Quercus floribunda-
Rhododendron arboreum apresentou a densidade arbórea máxima e o Abies pindrow-Betula
utilis o mínimo. A Myrsine africana foi a espécie arbustiva dominante. A diversidade arbórea
máxima e riqueza foi registada para a estação Daphiadhura enquanto a estação Vinaiyak
expressou a diversidade arbustiva máxima. Encontrou-se que a Pinus wallichiana, Betula
utilis, Tsuga demosa, etc. eram espécies arbóreas raras.
Key words: Forest conservation, Himalaya, Himalayan forests, India, ordination,
rare species, vegetation community.
Introduction
Himalaya, the youngest mountain system of
the world, constitutes an important link between
the vegetation of the southern peninsular India
on the one hand, the eastern Malaysian, the
north-eastern Sino-Japanese and the northern
Tibetan areas on the other (Puri et al. 1983).
Several studies have described the vegetation of
Kumaon (Dhar et al. 1997; Rikhari et al. 1989a;
Singh et al. 1984; Singh & Singh 1984; Singh &
Singh 1987; Singh et al. 1987; Tiwari & Singh
1985; Upreti et al. 1985) and Garhwal Himalaya
(Anthwal et al. 2006; Kumar & Bhatt 2006;
Nautiyal et al. 2004). Some of the studies
described altitudinal variation in vegetation
(Adhikari et al. 1992; Saxena et al. 1985) and
reported that vegetation types differ with change
in altitude. However, Puri et al. (1983) observed
that geology and soils may exercise a far greater
influence on the distribution of vegetation types
than the altitude or climate.
Some pioneering contributions on
phytosociology (Ralhan et al. 1982; Saxena &
Singh 1982) and population structure (Saxena et
al. 1985; Singh et al. 1987) of certain central
Himalayan forest types have already been
reported. The main objectives of this paper are: (i)
to describe structural attributes (density, species
diversity and richness) of tree, shrub and ground
layers; (ii) to identify predominating communities
of trees and ground vegetation, and plant species
of special concern, and to further identify the
localities having rare plant communities needing
protection.
Materials and methods
Study area
The study was conducted in 23 forest stands
including Binsar Wildlife Sanctuary (BWS) and
Askot Wildlife Sanctuary (AWS), in five districts;
Almora, Bageshwer, Champawat, Naini Tal and
Pithoragarh of Kumaon Himalaya (28° 43' 55" to
30° 30' 12" N latitude and 78° 44' 30" to 80° 45' E
longitude) covering an area of 21,032 km² in the
Uttarakhand state of India (Fig. 1, Table 1).
Kumaon Himalaya is altitudinally divisible into
subtropical (300 to 1500 m), temperate (1500 to
3500 m) and alpine (>3500 m) zones (Saxena et al.
1985). Annual rainfall peaks at about 1200 m
altitude (4100 mm) and gradually declines to 670
mm at 2700 m (Saxena et al. 1985).
Sampling procedures
Overall 902 sampling plots were laid in the 23
forest stands (details in Table 1). Vegetation was
sampled along existing forest trails which passed
through all the major habitat types to permit
sampling of different habitats in equal proportion
at each site. In each stand, sampling plots were 50
m apart, and each was laid at a distance of 10 m
from the edge of the trail on either side to avoid
sampling of the relatively disturbed vegetation.
Number of plots sampled in different stands is
given in Table 1.
At each sampling plot, a 10 m radius circular
plot (Dombois & Ellenberg 1974) was established.
Trees > 4 m height were considered mature trees.
Species and their individuals were recorded for the