Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
Studies on human interference in the Dhaka Sal (Shorea robusta)
forest using remote sensing techniques
Md.Jinnahtul Islam
Bangladesh Space Research and Remote Sensing Organization (SPARRSO), Agargaon, Sher-e-Bangla Nagar
ABSTRACT: Bangladesh ie one of the most densely populated countries in the World. Because of the increasing
population her demand for land and food are increasing day by day. Consequently the human interference on the
forest areas are also increasing. The landless peasants encroach the forest areas cut and remove trees over
night and convert forest land into dwelling houses and agricultural fields. In the hilly forests, the forest
vegetation of the plateaus and valleys are cleared and terraced for cultivation. The present investigation
indicates that fresh encroachment by raising new huts and clearing new forest areas for cultivation are going
on thus causing severe problem. The objectives of this study are to identify on the aerial photographs and
Landsat imagery the agricultural lands, villages, huts, ponds and market places in and near the forest area.
The work also includes collection of data on human resources. The compilation of the data and information
will be useful for development, management and protection of forest vegetation. The data will also be useful
for the study of the human and economic resources of the environment.
1 INTRODUCTION
The Dhaka forest is a tropical moist deciduous forest.
This is one of the oldest natural forest of Bangla
desh. It is situated between 23°50' and 24°25' North
Latitude and 90°10' and 90 40' East Longitude. The
forest tract exists in 200 Mouza of 30 Union Councils
of Sadar North Subdivision of Dhaka District. It is
situated only 20 miles away from the Dhaka Metropo
litan city towards the North direction. The Dhaka
forest is a pure Sal (Shorea robusta) coppice forest
stands on the raised hillock like scattered patches
of land. Besides the Sal (Shorea robusta) other
species like Dhaman (Grewia species) Gandhi Gazaril,
Amloki, Palash, Bohera, Kuteswar (Holerhena antidy-
sentrica), nonkata (Randia dumetorum), khutikat
(Glochindion velutinum), Gadila (Careya arborea),
Piralu (Randi uliginosa) etc. are found to be sca
ttered in the forest. Along the edges of the forest
various kinds of herbs and shrubs are also found to
grow along with Sal. Wild life have already been
eradicated from the forest area without some minor
species of birds and animals. The forest patches are
of different size extending up to the maximum size
of 500 acres. Some of them have only few trees and
some of them have converted into scrub forest. The
forest is inextricably mixed with habitation and
agriculture.
The mean maximum temperature of the area were
found to be 85 F over the last ten years. The mean
annual rainfall were found to be 70 inches over the
same period. The relative humidity ranges from 96$-
41$ during the early and late hours of the day time.
Thus the climate of the area may be taken as mode
rately humid and the area always remain pleasant.
Due to high population density and subsequent
loss of ecosystem the forest area has lost its ori
ginal cover density and vigour. The changes has been
taken place mainly due to human interference in the
forest. The type, cause and the result of human
interference has been discussed in the main context.
2 HUMAN INTERFERENCE
Illegal encroachment and thereby deforestation of
the forest land is the worst type of human inter
ference in the forest. The increasing rate of the
propulation has created severe land hunger in the
area. For the increased pupulation more lands are
required for habitation and cultivation. The arable
lands are already insufficient and the habitation
are thickly populated. As a result they do not find
any other alternative way without clearing some forest
land adjoining their agricultural land and homesteads
to meet a portion of their demand. Some times they
clear lands in the deep forest areas and start a new
settlement. As the forest is inextricably mixed with
habitation and scattered in small patches, the pro
tection of the forest from the encroachers is very
difficult by limited number of forest staff whose
head quarters are miles away. The sudden change of
Government and their policies, the disturbance period
during the sixties, the liberation war of 1971 and
the subsequent deterioration of law and order situa
tion in the country exerted substancial influence
upon this forest area. A s a result about one third
of the total area of the forest went under the illegal
possession of the encroachers.
Illicit felling and pilferage of forest produces
is another type of human interference in the forest.
As there is no large industry and cottage industry,
unemployment problem is increasing day by day with
the increase of population. The landless and unemploy
ed people finding no other alternative way of earning
their livings, gradually practice to collect forest
produces by illicit felling and selling them in the
near by market. Due to excessive price of the forest
produce they become habitual smuggler.
The fuel problem of the people living in the forest
area is another cause of deforestation. They do not
get gas and electricity for their daily common use.
Naturally they have to depend upon the fire wood to
meet up their coocking fuel, A s the fuel wood is out
of their buying capacity they generally extract them
from the forest. Besides the fire wood they also
collect the house posts and thatching material from
the forest. A s a result a vast area has been converted
into scrub forest of little value.
3 AGRICULTURAL FRACTICE IN THE FOREST
It has been stated that the forest area is an undulat
ing landscape consisting of high lands locally called
"chalas" which are intercepted by numerous narrow
depression called "Baid". The chalas look like float
ing islands over the areas. The forest crop and the
habitation exist on these chalas. The "Baids" are used
as paddy field. Both the Aus and transplanted Aman are
practiced there. On the "chalas" fruits and seasonal
vegetables are grown. Due to insufficiency of agri
