Forests in Arunachal Pradesh
The forests of Arunachal Pradesh possess a phenomenal range of biological diversity,
both in flor and fauna. The forests are also home to sizeable tribal population
which continues to live in close association with nature and utilises a wide
variety of forest resources for sustenance and livelihood. Nature has been exceedingly
kind and has endowed this beautiful State of Arunachal Pradesh with diverse
forests and magnificent wildlife. The richness of life forms i.e. the flora
& fauna that occur in these forests presents a panorama of biological diversity
with over 5000 plants, about 85 terrestrial mammals, over 500 birds and a large
number of butterflies, insects and reptiles.The vegetation of Arunachal Pradesh
falls under four broad climatic categories and can be classified in five broad
forest types with a sixth type of secondary forests. These are tropical forests,
sub-tropical forests, pine forests, temperate forests and alpine forests.
TROPICAL FORESTS
These forests occur up to an elevation of 900 metres above MSL . They are persent
in all the districts along the foothills . These forests can further be classified
into two main types viz. tropical evergreen forests and tropical semi evergreen
forests.
SUBTROPICAL FORESTS
This type of forests occur in districts between altitudes 800m to 1900m. These
are essentially evergreen and dense in nature. The trees attain large dimensions
(25-40m high). The forests are rich in species diversity and dominated by Fagaceae
members.
Castaniopsis lidica, C. armata, Quercus lamellose, Q. griffithili, Q. spicata,
Q. Semiserrata, Q. fenestrala, Michelia oblonga, Manglietia insignis, Ostodes
paniculata, Ulmus lancifolium, Engelhardia spicata, Ficus spp. Acer oblongum,
Schima wallichji, S.khasiana, etc. are the dominant tree species. Luxurious
growth of climbers, orchids & ferns, occurs in these forests.
PINE FORESTS
These forests extend both in the subtropical and temperate belt in between 1000
m to 1800 m elevation. These are generally met with in rain shadow area and
are represented by three different sepecsies viz. Pinus roxburghii, P. wallichiana
and P.merkusii., is found in Rupa and Dirang valley of Kameng district and forms
either pure stands or occasionally mixed with P. wallichiana, Quercus spp, Prunus
sp. Etc. P. wallichiana is widely distributed in Rupa, Dirang valley (Kameng
district), Hapoli ( Lower Subansiri district), Mechuka (West Siang district),
Anini (Dibang valley district). and Melinja ( Lohit district). In Kameng, Siang
and Lower Subansiri district it is found in nearly pure stands or less frequently
mixed with P. roxburghii, Quercus spp. Lyonia sp. Etc.
In Dibang valley they are found in association with Betula alnoides, Alnus nepalensis,
Lyona ovalifolia, etc. In Lohit district it is less extensive and is associated
with Tsuga dimosa, Pinus merkusii, occurs in Lohit district along the Lohit
valley extending from Kharang (Hawal) to Dichu.
TEMPERATE FORESTS
Occur in all district as a continuous belt and can be divided into two subtypes
viz. Temperate broad leaved forests and Temperate conifer forests.
ALPINE FORESTS
This type of vegetation occurs on the peaks of higher hills above an altitude
of 4000 m upto 5500m above timber line. For major part of the year, the area
is covered by snow and plant activity is restricted to a few months when snow
melts.
As a rule there are no tall trees but dwarf branches and shrubs and mainly herbs
with deep roots and cushioned leaves and branches. The profusion of bright coloured
flowers which is purely seasonal for a brief period makes the area highly attractive.
Plans like Rhododendron nivale., R. anthopogon, R. thomsonii, Sedum sp.., Festuca
sp.., Rhodiola sp,.. Saxifraga sp. Saussaurea sp,. Arenaria sp,. Rheum sp. etc.
form the major constituent of this peculiar vegetation.
DEGRADED FORESTS
The common trees seen are Machranga denticulate, Mallotus tetracoccus, Callicarpa
arbnorea, C. vestita, Bauhinia sp,. Glochidion spp, and shrubs like Clerodendrum
spp. Randia sp. Rubus sp,. Viburnum sp. Croton caudatus, Capparis spp., Eurya
acuminata, Dalbergia sp. etc. and also obnoxious weeds like Mikania micrantha,
Eupatorium odoratum, etc.
BAMBOO FORESTS
These are seen as bambaoo breakes up to 2000m altitude throughout the State,
Bamboos grow mostly in pure stands with very less of associated species. Normally
bamboos appear in areas abandoned after shifting cultivation, where they colonise
fast. Bamboos of Arunachal Pradesh are Bambusa tulda, B. pallida, Dendrocalamus
hamiltonii, D. hookerii, Pseudostachyum polymorphum, Chimonobambusa sp. Cephalostachyum
sp. and Arundinaria spp. , Phyllostachys sp. (both single stem bamboos) occsur
in higher elevation 1000-2000m.
GRASSLANDS
Grasslands form a main feature of vegetation in reverine plains and at higher
elevations. This seral type is maintained through recurring annual fires at
higher elevation and excessive grazing at lower elevations. In lower elevation,
Saccharum spontaneum, S. arundinaceum, Neyraudia reynaudiana, Chrysopogon aciculatus,
Chrysopogon aciculatus, Imperate Cylindrica, etc. associated with a few sedges
like Cyperus sp., Scirpus sp.., Fimbristylies sp., etc. are seen commonly in
grasslands. A few trees scattered at lower elevations, like Macranga denticulate,
Bombax ceiba, Duabanga grandiflora make the grassland are prominent in pine
belt. Such grasslands support gregarious tall grasses viz., Thysanolaena maxima,
Imperata cylindrical. Sporobolus sp.., Paspalum sp., etc
