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CLIMATE AND VEGETATION OF STUDY SITE
17
Survey of orchids was carried out from various grasslands,
agricultural lands and forest of Khasi Hills, Garo Hills and adjacent areas
of Meghalaya (Fig. 1). Their habit, habitat and frequency was observed.· Plants
·of different orchid species were collected and maintaine~ on charcoal and
soil mixture, fl11ed in earthen pots. Few epiphytic orchids were grown on
old dead logs under semi-controlled conditions (in net houses) in Botany Depart
ment, School of Life Sciences, North Eastern Hill University, Shillong. (latitude"
• • 25'34 N and longitude, 91 '56 E, altitude)'1956mm)
The orchids, for the present study, were divided into two
categories:
1) Terrestrial orchids
The orchids, which were found growing in soil of grasslands,
agricultural fields with weeds, grasses and in the forest floor with decaying
rich organic matters.
U) epiphytic orchids
The orchids which occurred on the trunk and branches of
tree species along with or without lichens, mosses and ferns and other epiphytic
vegetation.
SoU
Shillong plateau had mild undulatus topography. The soU
is laterite with reddish brown colour and the texture is sandy-loam at the
surface end and silty-loam at deeper layers. It had originated from the hard
rock representing gncises, schists and granite. Zimba (1977) had proposed
that Shillong plateau and its surrounding hills might have uplifted from sea
bed along with origin of great Himalaya during mesozoic and early tertiary
times. The soU is rich in organic matters and nitrogen but acidic in reaction.
Fig. I Map of Meghalaya showing the place of orchid collection.
(I = Place of collection; • _ study site)
9/0' 9j1- 912'
t MEGHALAYA
N ASS A
."'. .-.!: , '- ,... • .", , 26 .... . ."". . 26' • ...-.~. j j J Burnihot.l" '._0-' '" ,., ~ . j \
o'\. _----, f/'. o~'\. .' ~o • NonQPoh 07
.,-.... . I "C:J ?,.. o-~ i !" t:::.. ~\" Y"· I ." ..... ___ -----~ . I r~ ~ , I V \. c;, \\ .Umsnino , ....... .,.0",-o -~ C) \ ) ':\\,...v y..
v~ I ~ , \. .:t-~cf) / ,) • 8arapani, ."\ ~ • ,C) I ~~ .// ,/ ~HILlONG oJ"., ,.0"; ~o • I WiliiomNagor ~ / 'l.Imp1ino"1 ",
, • ~ .Turo) e f \ -' • Upper Shirllong '1 c, ( Is- Mawph/ono I eJowai ......
." ..... - I r , I" ----- \ EAST KHASI HILLS ) ~. . ~ '- \ "') , ~ \ ~ C)~ ~C)) _ .J ,'I- r • .,.".-,,\. \- ~9'(\C) ,,~ ~\~'''M awsanr~~herrapunjtMf~" l.
~ " ~~o C)c\e~" l,0o,j" ~ " _ '-._ Saghmara Rongra \ ~C)'(\ .". • , • Shell2-. ~'I- ,.
-.- • - • .........-.-.. • ..... -Sal.at ._.. z .'-• ..,., ..... -.... ~.-.--. . ....... r l. • .,.~- ~. • • ." BAN G LAD E S. H Ie 9 tp 2[> 3f> 4p Km. ~.,,- .J
-.J 910· 911· !.l2- STUDY ARE~_
Fig. ,
6 Fig. 2. Meteorological data for minimum and maximum temperature ( C),
relative humidity (96) and rainfall (mm) for the year 1982-83 of study
site in Shillong.
o RAINFALL
(IDJ MAX. TEMPERATURE
• MIN. TEMPERATURE
901 JOr • HUMIDITY
751 "- --"-- ~ 700 2
u om .... ..../ "'- ""V 11111 I I 11111 11111 600 >- 0 .... 560 w 20 ~ ~ 500 ,.... ;::J :J ~ l- E
w45 c( E ~ 15 400 -" w
:! a. ...J ...J
Z ~ 300 <: w LLJ u.. u30 1-10 z IX
w c( 0.. 200 ~
1 5 5 .11111_ 1111- • 1111_ • 1111_ • 1111_ I 1111_ I 1111_ I
100
SEP OCT NOV DEC! I JAN FEB MAR APR MAY JUN JUL AUG SEP I
1982 MONTHS 1983
Fig· 2
18
The vegetation of Meghalaya can broadly be classified into
(i) Subtropical forest
(ii) The mixed evergreen forest
(iii) Temperate forest
(iv) The rolling grassland
The sub-tropical pine forests represent biotic climax, dominated
by Pinus kesiya along with some tree species like Alnus nepalensis, Schima spp.,
Quercus spp., Cedrus deodara, Cryptomaria· japonica etc. and some other trees,
shrubs and herbaceous species like SympLocus spp., Rhododendron arboreum,
Lantana camara, Eupatorium spp., Anaphilis spp., and Desmodium spp. etc.
Mixed sub-tropical forests are confined to restricted areas and are
much disturbed. These are dominated by Schima spp., Quercus spp., Alnus nepale
nsis, Erythrina arborescens and a number of rosaceae members.
Temperate forests are elavated from 1800 m and above. The true
temperate vegetation which represents the richest flora (in preserved/sacred
forests) and gives an indication that probably the entire area was once covered
by such type of dens·e vegetation but now has been disturbed due to human acti
vities. In such forests the common trees namely Quercus griffithii, Myrica escu
lenta, Betula alnoides, Rhododendron arboreum, Castonopsis spp. Photenia notoniam
etc.; shrubs like, Daphne spp., Osbeckia spp. and beautiful orchids like Dendrobium
spp., Coelogyne spp., Cymbidium spp., Oberonia spp., Pleione spp., Pholidata spp.,
Eria spp. etc. are commonly encountered. The epiphytic plant species comprised
of lichens, mosses and ferns as dominant species on the tree trunks and branches
19
of old tree in moist humid forests.
The· grasslands represent most important vegetation type (ground
flora) of this region. Most of the grasslands are in the different stages of sereal
succession. The primitive agriculturtal LPc'.-tlce i.e. shifting cultivation locally
known as Jhuming is commonly used for raising the agricultural crops in the north
eastern region. The extensive use of jhuming is main factor in resulting the genesis
of grasslands in the region. Other biotic and human disturbances have also pro-
moted the process. The grasslands consist of dominant species like Paspalum
dilatatum, Pennisetum cladestinum, Imperata cylindrica, Panicum brevifolium,
Cyperus spp., Fimbristylis spp., Arundinella spp., Trifolium repens, Cassia spp.,
Desmodium spp. etc. and some beautiful terrestrial orchids like Spathoglottis
pubescens, Spirenthus spp., Herminium spp., Habenaria spp., Arundiana spp., Paphi-
opedilum spp. etc.
Climate
Shillong climate is very much influenced by the south-west monsoon
and north-eastern winds.
Therefore, the year can be divided into four seasons:
I Spring season - March and April.
II Summer (Rainy) season - May to September
III Autumn season - October and November
IV Winter season - December to February.
During spring season atmosphere gets warm gradually as compared
to the preceding winter months. The maximum temperature reaches during the
period of April to the June-JUly. The average maximum temperature at Shillong o
recorded during the study period was 24-.8 C and the average minimum temperature
20
o 12.52 C. Rain starts at the end of April and continues upto September. The monthly
average rainfall normally is 212.02. mm. The average humidity (%) ranges between
61 to 88.5 (Fig. 2). October and November represent a typical autumn season
with mild cold and usually with less rain. The winter season can be characterised
by low temperature, from cool to cold one. The temperature drops down to a o
minimum of 1 C in the early period of January and occasional frost can appear.
Sometimes there is rain during the month of March which is helpful for the ger-
mination and development of most of the trees, plants, and herbs.
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