Thesis

MATERIALS AND METHODS

CHAPTER 3: MATERIALS AND METHODS

The upland watershed spread over Chittagong and Chittagong Hill Tracts in Bangladesh

was green with the presence of natural forests. Area affected by deforestation in

Bangladesh is either not surveyed or mapped and areas never determined except periodic

ocular observations. The different estimates of deforestation reported in various sources

are not mutually consistent (FMP, 1992). In 1927 Bangladesh had 20% natural forest and

at present 6% of its forestland is covered with natural trees. The annual rate of

deforestation in Bangladesh is very high (3.3%) compared to other six South Asian

countries (0.6%) during 1981-1990, the rate again increasing over the decades. The

estimated deforestation of about 8,000 hayr-1 during the 1970s, increased to about 37,600

hayr-1in the 1980s (FMP, 1992). In the hill forest including USF tree cover area is 54% of

the land managed by Forest Department. The period between mid-1960 and mid-1980s

Cox’s Bazar region lost 36% and Chittagong region 58% tree cover. In other words,

within this 20 years time denudation took place to 18,800 ha out of 52,800 ha in Cox’s

Bazar, while to 57,500 ha out of 99,300 ha in Chittagong forest area. Deforestation also

occurred in all the Reserved Forests in CHTs, but the extent varies from forest to forest

(FMP, 1992). Of the major Reserved Forests in the CHTs Rankhiang was the worst

affected forest. During the period from 1963 and 1983, the extent of non forested area at

Kassalong Reserved Forest increased from 3 to 32%, at Sangu and Matamuhuri Reserved

Forests from 0.5 to 23% and, at Rankhiang Reserved Forest from 3 to 49% (FMP, 1992).

Deforestation increased at Kassalong Reserved Forest due to encroachment by destitute

jhumias displaced by plain land settlers and also because of illegal logging. Within the

Rangamati district, deforestation in the protected forest was caused by organized gangs.

Development activities such as dam, highway, road construction and other infrastructure

development also increased deforestation rate. Along with specific causes, generalized

reasons for deforestation in hilly region including Chittagong and Cox’s Bazar district are

policy weakness, inappropriate and over exploitation of forests, law and order failures

and increased habitations. Deforestation process involves cutting and lopping of trees,

excessive grazing, illicit felling, fuel wood collection, burning, uncontrolled and wasteful

Institute of Forestry and Environmental Sciences Page 22


felling, conversion of forest to agriculture through clearing and burning, migration of

landless people in the forest areas and encroachment. The study included 12 deforested

locations spread over in Chittagong region and 7 clear felled area Chittagong district

(North); and 14 shifting cultivated area in CHTs. Each of the sites with activities are

described bellow:

3.1 DEFORESTED AREA:

3.1.1 DULAHAZARA:

Dulhazara is an important forest belt of natural Dipterocarpus spp. (garjan) in

Chittagong-Cox’s Bazar region. The natural garjan forest with an area of 900 ha at

Dulhazara declared as Safari Park in 1996 (Choudhury et. al., 2004). The Dulhazara

Safari Park is under the administration of Wildlife Management and Nature Conservation

Division, Chittagong. The park lies between 20043Ń to 21056Ń latitudes and between

91050É to 92023´ E longitudes beside Chittagong-Cox’s Bazar road. Topography of the

park is almost flat and little undulating with a slope of 0 to 4%.

Natural forests: Natural forest of Dulhazara Safari Park is characterized by the presence

of dominant species such as Dipterocarpus spp. (garjan), Syzygium spp. (jam) and 2 types

of canes and shrub species like Clerodendrum indicum, Mussaenda roseburghii,

Melastoma malabatricwn etc. on gentle slope and several natural and artificially created

lakes for wildlife water supply. About 92% trees in the forest were garjan, 7% jam and

remaining of other tree species. Tree canopy coverage of the forest ranged from 10% to

50% and undergrowth coverage varied from 40% to 100% over the whole area of the

forest. Undergrowth composed of herbs, shrubs, climbers, bamboos and canes along with

remarkable amount of litter on the forest floor. Proportion of dominant garjan trees

falling in 21m – 40 m height class possessed 23%, in 10 m -20 m height class 33% and

in <10 m height class 44% and planted garjan trees mostly occupied this class. For

creating ecotourism facility, 12 km road network present inside the Safari Park. Natural

forest within the Safari Park falls under the tropical evergreen and semi-evergreen forest

bio-geographic zone (Khan, 1990). However, like other natural forests, vegetation of the

Dulahaza Safari Park was also variable in composition, coverage and height growth in

different parts of the natural forests. Therefore, soil profiles were studied and soils



collected from each horizon representing all variations of vegetation in the natural forest

of Dulahazara, as described below.

Old deer breeding area: This part of natural forest was in old deer breeding area on high

land at 9 m elevation having gentle slope ranging from 0% to 4%. This forest site lies at

21o40΄09΄΄N latitude and 092o05΄18΄΄E longitude. In this natural forest, vegetation was

the mixture of Dipterocarpus spp. (garjan), Syzygium grande (dhaki jam), Mangifera

indica (aam) and Macaranga peltata (meda) with their proportion of 68, 17, 10 and 5,

respectively. Tree canopy coverage of the forest was 40% and undergrowth coverage

varied from 70% having no grass vegetation, but 96% land covered with litter. At this

area bamboo clump covered 80% land during vegetation survey in 2007 and

Dipterocarpus spp. (garjan) and Aquilaria agallocha (agar) together covered 20% land.

All bamboo clumps were found to disappear in September 2012 during final visit to this

forest area due to natural succession of the vegetation. Mean diameter of garjan trees in

this part of the natural forest ranged from 60.50 cm to 66.25 cm and mean height from

21.70 m to 27.50 m. Mean height of S. grande ranged from 16.50 m to 25 m in this part

of the forest. The number of trees varied from 125 to 200 with mean of 167 stems per

hectare. Litter cover was almost uniform over the forest of depth 7.6 cm and weight 6490

kgha-1. Cimmamomum spp. (tejbahal) rarely present as undergrowth. At this site soil

profile comprised of A1, A2, B1 and C horizon and soil texture up to B1 horizon i.e. up

to 76 cm depth, was sandy clay loam and in the C horizon of 76 cm to 96 cm+ contained

sandy clay texture.

West of Birds Avery: This part of natural garjan forest was to the west of Birds Avery

on high land at 9 m elevation having a gentle slope ranging from 0 to 4%. This forest site

lies at 21o40΄10΄΄N latitude and 092o05΄02΄΄E longitude. In this part of natural forest,

vegetation was the mixture of bamboo, bet and others. Tree canopy coverage in the forest

was 30% and undergrowth coverage 90% having no grass vegetation with litter coverage

of 70-96%. Bamboo constituted 80% during vegetation survey in 2007, and cane and

other species 20% as undergrowth. Similar to above described area bamboo was absent at

this part of the forest also in September 2012. The mean diameter of garjan trees ranged

from 46.5 cm to 66.0 cm and mean height varied from 23.83 m to 24.5 m with tree



densities ranging from 100 to 225 and mean of 168 numbers ha -1. The height and

diameter of S. grande (dhaki jam) were 16 m and 60 cm and of Alstonia scholaris

(chatim) 10 m and 6 cm, respectively. Litter cover was almost uniform over the forest of

depth 3.67 cm and weight 5323 kgha-1.

Asian and African Herbivores Animal Enclosure: This part of natural garjan forest

was in Asian and African Herbivores Animal Enclosure on high land at 10 m elevation

having a gentle slope ranging from 0 to 4%. This forest site lies at 21o40΄11N latitude and

092o05΄30E longitude. This site within the natural forest was fully covered by planted

garjan trees. Three strata from lower to upward in the garjan plantation were 5 m, 8 m

and >10 m height. Tree canopy coverage of the forest was 70% and undergrowth

coverage 50% having no grass vegetation and 90% land covered with litter. Garjan

constituted 80% as tree cover and Melastoma malabathricum (bon tezpata) and other

herbs and shrubs constituted 20% as undergrowth. In the forest, mean diameter of garjan

trees ranged from 9.81 cm to 12.95 cm and mean height varied from 8.15 m to 8.53 m

with tree densities between 3100 and 3700 with mean of 3400 stems ha -1. Litter cover

was almost uniform over the forest of depth 7 cm and weight 4607 kgha-1.

North east of Lion Enclosure: This forest part was to the north east of Lion Enclosure

on high land at 10 m in elevation having a gentle slope ranging from 0 to 2%. This forest

site lies at 21o40΄24΄΄N latitude and 092o05΄17΄΄E. This natural forest area was fully

covered by garjan tree. Tree canopy coverage of the forest was 50% and undergrowth

coverage varied from 40-70% having no grass vegetation and 80% land covered with

litter. Syzygium grande (dhaki jam) constituted 60% as tree and others such as

Cimmamomum spp. (tejbahal) and cane as undergrowth constituted 40%. In the forest,

mean diameter of garjan trees ranged from 52.5 cm to 58.22 cm and mean height varied

from 17.25 m to 17.72 m with tree densities ranging from 200 to 400 and mean of 275

stems ha-1. Two S. grande trees were also found at this forest part. The mean diameter

and height of S. grande were 49.5 cm and 14.5 m, respectively. Litter cover was almost

uniform over the forest of depth 4.5 cm and weight 6297 kgha-1.

West of observation tower: This natural garjan forest area was to the west of high

observation tower and above branched lake on high land at 8 m elevation having gentle



slope ranging from 0 to 4%. This forest part lies at 21o39΄52΄΄N latitude and

092o05΄38΄΄E. This forest area covered with garjan trees. Tree canopy coverage of the

forest was 10% and undergrowth coverage 100% having no grass vegetation and fully

(100%) covered with bamboo clump. Similar to other parts of the forest bamboo clumps

were found to disappear from this forest part also during final field visit in 2012.

Syzygium grande (dhaki jam) constituted 60% and other vegetation such as

Cimmamomum spp. (tejbahal), cane constituted 40% as undergrowth. In the forest, mean

diameter of garjan trees ranged from 18.50 cm to 45.50 cm and mean height varied from

13 m to 17.5 m with tree density 200 numbers ha-1.

Deforested land: The deforested land possessed in the past similar ecological

characteristics as exists in natural forest vegetation of Dulhazara Safari Park. In the near

past, the whole area of Dulahazara was covered with dense evergreen forest dominated

by tall trees such as Anisoptera glebra (boilam), Dipterocarpus spp. (garjan), Artocarpus

chaplasha (chapalish), Hopea odorata (telsur) etc. Then diversity and density of the plant

species was very high with the presence many wild animals such as Royal Bengal tiger,

Chitabag, elephant, deer (Choudhury et. al., 2004). Survey done on February 2007

showed that the land comprised of small sized scattered distribution of Hollarrhena

antidycenterica (kuruz), Dipterocarpus turbinatus (telia garjan), Emblica officinalis

(amoloki), Cimmamomum spp. (tejbahal), Ficus benghalensis (bot) and Syzygium

fruticosum (puti jam) with herbs and shrubs of 1-2.5 m height giving coverage of 30-

40%. Only about 24 garjan trees of 10 m – 20 m height class and only 3 trees > 20 m

height class on about 800 ha deforested land. No litter coverage was found on the floor

due to complete burning in places. The land was disturbed through collection of forest

products such as fuel-wood, small sized construction timber, grasses and other products

by people residing inside and around the forest and clearing of forest areas in some places

for the cultivation of seasonal agriculture crops. Deforested land is thus unprotected.

The deforested land 1 was on low hill top at10 m elevation of gentle slope ranging from

0 to 4% to the 3 km north-east of Dulhazara Safari natural Park. This site was at

geographical position of 21o40΄08N and 092o04΄53E and possessed similar ecological

characteristics except the vegetation. The deforested land with slope of 2-10% contained



no trees and vegetation consisting of herbs and shrubs of height 1.0 m – 2.5 m with

coverage of 30-40% and litter coverage 30%. During survey on February 2007, the land

was barren and burnt for agricultural practice, but about 30 years before this area

possessed Dipeterocarpus spp. (garjan) forest, as informed from local people and similar

to existing Safari natural Park, and now fully destroyed due to illicit felling. Litter depth

of this site was 1 cm and weight 400 kgha-1.

The deforested land 2 with slope of 0 to 4% contained no trees and vegetation

consisting of herbs and shrubs of height 1-2.5 m having coverage of 30-40%. This site

was at geographical position of 21o39΄55N and 092o05΄50N having no litter coverage

because of complete burning and ashes present on surface soil.

The deforested land 3 was at geographical position of 21o39΄58N and 092o05΄50E on 0

to 4%, land contained no trees and vegetation consisting of herbs and shrubs of height 1.0

m – 2.5m having coverage of 70%. Litter coverage was 60% with depth of 2.33 cm and

weight 1440 kg ha-1.

3.1.2 Tonkawati

Tonkawati forest is situated in the transition zone of Bandarban Hill District and

Chittagong District. This forest covers Tankawati Beat under Padua Range of Chittagong

South Forest Division and Tankawati Range of Bandarban Forest Division. This forest

lies between 21057´8´Ń and 2209´13´Ń latitudes and between 9207´32´É and 92012´22´É

longitudes. Tankawati forest covers five moujas, of which four in Chittagong district and

one in Banderban district. The four moujas under Lohagara Upazilla of Chittagong

district are Paharchada, Maijbilla, Rajghata and Charamba. Tankawati is the name of

Mouja as well as Range in Bandarban Sadar Upazilla of Bandarban district.

Natural forest: Tankawati natural forest covered 1741 ha land, of which 810 ha to 1012

ha compact high reserved forest. The forest was characterized by the presence of

dominant species such as Dipterocarpus turbinatus (garjan) and Artocarpus chaplasha

(chapalish) to the top storey and Pterospermum acerifolium (mose) as middle storey and

Meloanna baccifera (muli) clump present as undergrowth. Tree canopy coverage of the

forest ranged from 10% to 70% and undergrowth coverage varied from 40% to 100%.



Tree size varied greatly in this natural forest. Mean height of the dominant species was 30

m with close canopy coverage. Litter cover was almost uniform over the forest with

depth of 10 cm giving mean litter weight 5500 kgha-1.

Natural forest 1: This was a good natural D. spp. (garjan) forest on northern aspect at

21°58′702″N and 092°11′745″E geographic position having large and well crown

coverage and completely covered with litter on a medium high hill having 12% slope.

This part of forest comprised of 60-70% trees and 30-40% other vegetation. This part of

forest was mostly occupied by Dipterocarpus turbinatus, (telya garjan - 100 stems ha-1),

Dipterocarpus gracilis (dhulia garjan- 75 stems ha-1) and other tree species included A.

chaplasha (chapalish), Tetrameles nudiflora (chandul), Quercus spp. (batna) etc. giving

70% tree canopy coverage. Combining all tree species in this part of forest had 375 stems

ha-1. Forest floor was fully covered with 8 cm thick litter giving accumulation rate 4620

kg ha-1. From ocular observation this part of forest was found free from soil erosion.

Natural forest 2: This part of natural forest on northern aspect was on 15% slope, where

13 tree species recorded. Among these, dominant tree species were tellya garjan (100

stem ha-1) followed by Dipterocarpus gracilis (dhulia garjan), Illex godajam (godajam)

(75 stem ha-1), Castanopsis indica (batna), A. chaplasha (chapalish), Brownlowia elata

(moch) (50 stem ha-1). All other tree species in this part of forest had 25 stems ha-1.

Combining all, 313 trees ha-1 was existed in the forest. The maximum dbh were found at

this part for Dipterocarpus turbinatus (teliya garjan) D. gracilis (dhulia garjan) and B.

elata (moch). Here, top storey coverage was 90%, middle storey 60%, and ground storey

coverage 60% with no grass vegetation. Forest is of 3 storied, being upper story 26-30 m,

middle 12-15 m and lower one 5-7 m. Both depth and litter fall accumulation were

variable within the forest. Litter depth varied from 2 to 7 cm with accumulation of 4080-

4600 kg ha-1 with mean of 4280 kg ha-1 and depth of 4.83 cm. The northern aspect of this

forest also contained natural bamboo as under growth of D. spp. (garjan) trees. From

ocular observation this site was found free from soil erosion. Tankawati natural forests

were rich in natural regeneration and distribution of different trees quite good. The

regeneration of Dipterocarpus spp., Swintonia floribunda and Artocarpus chaplasha are

satisfactory by area, number and age class in different portions of the forest.



Deforested land: The natural forest consisted of Dipterocarpus turbinatus (garjan),

Artocarpus chaplasha (chapalish) with several other tree species on low hill, although a

major portion has been deforested due to illicit felling. Topography of the land is

moderately steep on western aspect. Soil profile was dug on a patch of barren/deforested

land at lower part on 20% hill slope on western aspect. On both sides of the deforested

land were natural forest and the site lied in between agricultural land on valley and

natural forest. In this area, very few under growth were present, 80% land grass covered

and litter almost nil.

3.1.3 Chunti Wildlife Sanctuary:

Chunuti Wildlife Sanctuary is under Chunuti Forest Range of Chittagong South Forest

Division. The sanctuary is located at 22008'N latitude and 91058' to 92005'E longitude,

about 70 km south of Chittagong City and to the west side of Chittagong-Cox’s Bazar

highway (WCMC, 1998 and Khan, 1990). This sanctuary covered a total area of 7764 ha

of reserved forest (Rahman, et. al., 2000). There were 8 forest Beats in Chunuti Wildlife

Sanctuary (Rahman, et. a.l., 2000) and the study area located at Chunuti Beat.

Administratively, the land is situated at Aziz Nagar Union under Lohagara Upzila in

Chittagong district. Each pair of land consisted of a Wildlife Sanctuary land and a

deforested land situated side by side on similar topographic position. The sanctuary area

is generally hilly to mountainous with shallow to deep gullies with gentle to steep slopes.

Surface soils on the alluvial plain and valley are mainly silt loam to silt clay loam,

moderately to strongly structured with neutral to medium acid subsoil (Rahman, et. al.,

2000).

First pair of land:

25 year old deforested land: The Chunuti wildlife sanctuary was established in 1986.

Deforestation and encroachment has already destroyed a major portion of this sanctuary

during the last decades (Rahaman, et al., 2000). The rate of deforestation was severe after

the liberation war of Bangladesh. The distance of this deforested land from the Arakan

Road is about 300 m and lies at an elevation of 25 m. According to the record of Chunuti

Forest Range, this land was completely deforested in the beginning of 1980 and thus, the

age of this deforestation land became 25 years.



Wildlife sanctuary land1: The adjacent compared forest land in the sanctuary was 200

m apart from the deforested land. Once the sanctuary was composed of about 477 plant

species of evergreen and semi-evergreen trees, shrubs, and herbs, but during the study

species composition and condition much changed compared to the past time. In this

sanctuary, only 20% species constituted natural and the remaining 80% planted species

by the Forest Department in 1978. The dominant tree species of this land was

Dipterocarpus turbinatus (telya garjan).

Second pair of land:

27 year old deforested land: The deforested land was 500 m apart and to the west of the

first deforested land. The topography of this land was also hilly and lied at an elevation of

20 m. The distance from the adjacent wildlife sanctuary land was 180 m and to the east of

the first deforested land. According to record of Chunuti Forest Range, the site was

deforested at the beginning of 1978 and therefore, deforestation age of this land was 27

years.

Wildlife sanctuary land 2: On this land, only 20% species was natural and 80% species

artificially planted by Forest Department in 1977. The land was hilly with an elevation of

30 m. The dominant species of this land was Dipterocarpus turbinatus (teya garjan).

3.1.4 Batali hill

The area was planted with Acacia auriculiformis in 1997 under the financial and

supervision by the Chittagong City Corporation. Only northern side of the hill was

planted leaving the southern, eastern, and western side barren. The top of the hill was also

not planted. The spacing was 2 m X 2 m in acacia mono-plantation. The growth of the

trees was better. Most of the trees already reached to a height of 12 m to 15 m and

diameter at breast height (dbh) between 12 cm and 18 cm. The height and diameter

increment were more vigorous in valley than that of mid slope and upper slope.

The encroacher built house on valley and top of the hill illegally without permission from

the proper authority. The settlers mainly came from Noakhali, Comilla, Feni and Barisal

districts. Hill cutting was recorded in the area by the encroacher for making houses.



3.1.5 Hazarikhil

This study area was at Hazarikhil Forest Range in Chittagong North Forest Division for

determination of effects of deforestation. This Forest Range is situated 45 km north of

Chittagong city and administratively at Harualchari Union under Fatickchari Upazilla in

Chittagong district. The area possesses sub-tropical climate with a long dry season

extending from October to May. Total forest area of this Forest Range was 4255 ha, with

legal status of reserve forest. Sampling sites both in deforested and natural forest covered

an area of 4 ha in two Forest Blocks, namely, Hazarikhil and Rangapani, lying between

22040N and 22043 N latitudes and between 90039.5E and 91042 E longitudes. About

50 years back, Hazarikhil area was rich in forest. The forest consisted of a mixture of

many tropical evergreen and deciduous species occurring in association with each other

and with bamboo jungle. Most of the area is now deforested with the presence of hardly a

few valuable forest species (SRDI, 2002).

With the objective to select representative study sites, a preliminary survey was done first

in Hazarikhil natural forest and its surrounding deforested area under Fatickchari

Upazilla. The survey also included identifying respondents and rapport building with the

local leader and interactive association with Hazarikhil Forest Range office to collect

factual information related to natural forest and deforested land. For selection of study

sites, personal contact was made with office of Chittagong North Forest Division and

base map collected from the office. To get more information about Hazarikhil Natural

forest, land acquisition records were searched in the office of Fatickchari Upazilla. No

record was found on deforested area of Fatickchari Upazilla, contact therefore, made with

Hazarikhil Range Office and local people, particularly old aged persons, to find out the

age of deforested lands. Map was consulted in detailed with Forest Range Officer of

Hazarikhil Range. He and his office staff helped to locate all the study sites in the field.

Thus, 5 sites from Hazarikhil natural forest and 5 sites from deforested area were selected

for collection of data on various aspects related to the study. Thus, selected five

deforested sites were of 15, 23, 33, 38, and 43 years old. Sampling points in the natural

forest and deforested land were at least 50 m inside from the boundary to avoid

interaction between the two land use types. Natural forest consisted of a mixture of

different species in association with bamboo jungle having 97% vegetation coverage. In



deforested land coverage was 20%, each for trees, shrubs and herbs. At Hazarikhil soil

sampling was done from 0-5 cm and 5-15 cm depth digging mini profiles. Hazarikhil was

under Chittagong North Forest Division. This location contained 5 pair sites representing

natural forest and deforested land. The deforested sites were of 15, 23, 33, 38, and 43

years old. Sampling points in the natural forest and deforested land were at least 50 m

inside from the boundary to avoid interaction between the two land use types.

3.1.6 Mandakini

To determine effect of deforestation this study was conducted at Mandakini Forest Beat,

Hathazari Forest Range in Chittagong North Forest Division. Two sites, one in plantation

at Mandakini Forest Beat and the other in adjacent deforested area, were selected for the

study. Sampling area both on deforested land and plantation of this Forest Beat covered

25 ha. Mean monthly temperature of this area varied from 19.8ºC in January to 28.6ºC in

May with mean annual temperature is 25.6ºC and mean annual rainfall of 2914 mm

(SRDI, 1991).

Plantation: This was a 9 year mixed plantation of Acacia auriculiformis (akashmoni) and

Acacia mangium (mangium) with 70% canopy coverage situated on the southern side of

Mandakini Forest Beat office on land with 15% slope. Undergrowth covered area was not

uniform over the whole plantation. Undergrowth in this plantation consisted of Mimosa

pudica (lajjabati), Caealpinia cristael (kootumkanta), Hyptic sauveolens (tokma),

Eupatorium odoratum (assamlata) etc. with a number of vines and creepers.

Deforested land: In deforested land had no tree and undergrowth consisted of Mimusa

pudica (Lajjabati), Caealpinia cristael (Kootumkanta), Eupatorium odoratum

(Assamlata), Mikania cordata (Tarakanta) etc. At Mandakini soil sampling was done

from 0-10 cm and 10-30 cm depth both from plantation and deforested land.

Degraded natural forest: This site was in degraded natural forest of Sitapahar at 49 m

elevation of a flat hill top on north-western aspect with adjacent very steep hill slope at

Rampahar Forest Beat, Kaptai Forest Range, Rangamati South Forest Division with



geographical position 22o29΄41N and 092o10΄20E. Vegetation consisted of few valuable

species like, Dipterocarpus spp. (garjan), Castanopsis tribuloides (lal batna) and

Swintonia floribunda (civit) with admixture of herbs, shrubs and important climber,

Entada phaseoloids (gilalata). Top storey canopy coverage of the forest was 30%,

undergrowth coverage 100% and ground vegetation coverage 18% in the forest. Forest

floor was uniformly fully (100%) covered with 11 cm thick litter layer giving mean

weight 1093 kg ha-1. However, forest contained good regeneration of tree species like

Syzygium grandis (jam), Mangifera longipes (uriam), Alastonia scholaris (chatim), D.

spp. (garjan), Lannea coromandelica (bhadi), Mucuna prurens (bandarhula) etc.

Different sized 12 tree species in 2 plots of diameter ranged between 6 cm and 55 cm and

between 3 m and 30 m with 225 stems ha-1in this degraded natural forest. Tree species in

the forest consisted of Pothos scandens (hatilata), M. longipes (uriam), Schima wallichii

(konak), L. coromandelica (bhadi), Diospyros peregrina (gab), D. spp. (garjan), A.

scholaris (chatim), S. grandis (jam) and Castanopsis indica (batna).

3.1.7 Jahajpura

Jahazpura is one of the oldest garjan sample plot of more than 200 years covering an area

of 700 m to 1300 m wide and 2 km long strip on almost flat land with 2% slope on north-

western aspect at 4 m elevation above MSL situated between sea and hills at Shilkhali

Forest Beat and Range, under Cox’s Bazar South Forest Division. According to personal

communication to Cox’s Bazar South Forest Division Office in September 2012 it was

known that Garjan Sample Plot covers 30 ha land and total land area under Shilkhali

Forest Beat covered 303.56 ha. This forest is about 10 km away from Teknaf lying at

21o1΄429΄΄N latitude and 92o11΄253΄΄E longitude. In this forest tree density was more in

the middle part and density decreased both in northern and southern part. From a

complete enumeration in Shilkhali garjan forest 5069 trees were found to grow having 27

different species. The dominant tree species in the forest was Dipterocarpus turbinatus

(telya garjan) the number of which 4760 constituted 93.30%. The next occurring species

was Hopea odorata (telsur) having 118 trees constituting 2.33% in the forest. The other

tree species that grew in the Silkhali forest from higher to lower or equal in proportion

were L. speciosa (jarul), Mangifera indica (am), Syzygium cumini (kalo jam), T. grandis

(teak), Bombax ceiba (tula), A. auriculiformis (akasmoni), Dillenia pentagyna (hargoza),



G. arborea (gamar), Terminalia belerica (bohera), Terminalia chebula (horitaki),

Macaranga denticulata (foke), Albizia lebbeck (kalo koroi), A. chapalasha (chapalish),

Ficus benghalensis (bot), Dillenia indica (chalta), Vitex peduncularis (arsol), Erythrina

variegata (madar) and Albizia chinensis (chakua koroi) constituting proportion between

0.73% and 0.02%. Other vegetation like grass, shrub and climber also grew as

undergrowth in the forest along with numerous naturally regenerated seedlings of garjan,

telsur, dhakijam, uriam etc.

Good garjan forest: Geographical position of this site was at 21o1΄429N and 092 011΄253E. At this soil sampling site surrounding canopy coverage by garjan tree was 80%

and jam 20% with undergrowth coverage of 90% including 30% grass vegetation and

20% herbs and shrubs. Number of garjan trees of diameter varying from 45 cm to 50 cm

and height from 23 m to 31m ranged between 175 and 200 ha-1 having 5.5 cm thick litter

accumulation of weight 1.05 kg ha-1.

Degraded garjan forest: At this soil sampling site, no garjan tree was present, but

adjacent site contained few medium sized garjan trees. However, vegetation composition

consisted of mainly herbs which changes seasonally. This site was at geographic position

of 210 01’784N and 92011.057’E at 4 m elevation. This site was a patch on flat to gentle

slope (2%) land.

Denuded land: The denuded land was a small hill top of 2.5% slope on sandy loam soil

having vegetation consisting of herbs and shrubs without any trees. In the past this site

possessed similar ecological conditions as exists in good garjan forest. However, existing

vegetation here was not static and changed repeatedly due to cattle grazing and growing

of agricultural crops by the settlers. No litter coverage was found on the floor, because

the previous garjan vegetation had been completely removed due to illicit felling over the

time. Human habitation was on this small hill and managed for household purpose.

3.1.8 Medakacchapia mature garjan forest:

Medakacchapia was a mature more than 100 years old natural garjan forest declared in

2005 as National Park situated 40 km north of Cox’s Bazar town beside Cox’s Bazar-

Chittagong Road. Administratively, Medakacchapia is a Forest Beat under Fulchari



Forest Range, Cox’s Bazar North Forest Division.This land is on 0-8% low hill slope at

14 m elevation above M.S.L. Canopy coverage of garjan trees in the forest ranged from

80% to 85% with undergrowth coverage of 70% to 80% having no grass vegetation.

Height of D. turbinatus varied from 23 m to 25 m and diameter from 64.43 cm to 72.57

cm with mean height of 24 m and diameter 69 cm showing little variation both in size

and density varying from 175 to 200 stems ha-1with mean of 183 stems ha-1. Litter cover

was almost uniform over the forest providing mean depth of 2.83 cm and mean weight

4033 kgha-1.

Deforested land: Deforested land is located at 0.6 km south from the above described

natural forest situated at Boroitoli with geographic position 21o48΄03΄΄N and

92o04΄43΄΄E. This deforested land contained 2 -3 garjan trees ha-1 on hill top only with

about 95% undergrowth coverage of height ranging from 1 m to 1.5 m with few grasses.

Litter depth was variable over the area with a mean depth of 1.83 cm and mean weight of

1033.3 kg ha-1. Soil profile was dug on lower part of the hill slope ranging from 5 to 25%.

3.1.9 Napitkhali:

General description: Napitkhali Forest Beat is situated about 35 km away from Cox’s

Bazar town, under Cox’s Bazar North Forest Division. The Beat possessed 974 ha forest,

of which 946 ha reserved and 28 ha protected forest. Topographically the forest area is

hilly having gentle to steep slope. In the area annual rainfall is very high being 4581 mm

in 2003. To select representative study sites, a reconnaissance survey was made covering

500 ha land at Napitkhali Beat to find out a pair site representing plantation with adjacent

deforested area.

Site description: In the plantation of the pair site, tree coverage was 78% and

undergrowth coverage 69%. However, their coverage was not uniform over the area. Tree

covered area ranged from 60% to 90%, while undergrowth coverage ranged from 60% to

80%. The plantation was a mixture of several species viz. Acacia hybrid, Acacia

auriculiformes, Syzygium spp. Etc with mean height of 9.51 m and dbh of 5.75 cm. The

dominant planted tree species were Acacia hybrid and Acacia auriculiformis. The



adjacent deforested site had no tree, grass and undergrowth, except some scattered fruit

trees planted by the owner.

3.1.10 Boroitali:

Natural forest: Boroitali Forest Beat is located by the side of Chittagong-Cox’s Bazar

Road, 85 km away from Chittagong city under Chunoti Forest Range in Chittagong North

Forest Division at geographical position of 21048΄005΄΄N latitude and 92004΄740΄΄E

longitude. This was a mixed forest comprised of tall natural garjan and replanted garjan

and jam species. Other associated species in this forest were Michelia champaca

(champa), Syzygium fruticosum (khudijam/banjam), Lagerstroemia speciosa (jarul)

Artocanpus chapalasha (chapalish) etc. Tree canopy coverage ranged from 80 to 95%.

Undergrowth coverage consisted of herbs and shrubs ranged from 70-80% with no grass

vegetation. Among tree vegetation Dipterocarpus spp. (garjan) constituted 80% and

Syzygium spp. (jam) and other trees covered about 20% in this forest. Mean diameter of

Dipterocarpus spp (garjan) trees was 36 cm and height 21 m. Diameters of

Dipterocarpus spp. (garjan) ranged from 12 cm to 95 cm and height from 12 m to 29 m.

Height of dominant trees was 18 m -29 m and shrub height 0.5 m -1.2 m. Density of trees

in the forest was not uniform and varied greatly ranging from175 stems ha-1 to 325 stems

ha-1 with a mean of 258 stems ha-1. Herbs, shrub and other vegetation as undergrowth

coverage were 60%. Litter cover was almost uniform on forest floor of depth 1.67 cm and

weight 783.3 kg ha-1.

3.1.11 Soil and water conservation centre in Bandarban

The Bandarban Soil and Water Conservation Centre is situated by the side of Bandarban-

Chittagong Road and 5 km to the south of Bandarban City. It lies between N

and N latitudes and between E and E longitudes. This

centre covers 27 ha land having elevation ranged from 92 m to 133 m above MSL. The

centre is abundant with numerous plant as well as animal species. The major timber tree

species are Tectona graandis (teak), Bombax ceiba (shimul), Ficus hispida (dumur),

Dalbergia sissoo (sisoo), Melia sempervirens (ghora neem), Azadiracahta indica (neem),

Swietenia mahagoni (mahagoni), Leucaena diversifolia (ipil ipil), Murraya paniculata

(kamini), Erythrina variegata (mandar), Albezia procera (koroi), Delonix regia



(krishnachura), Anthocephalus cadamba (kadam), Cassia fistula (sonalu), Dipterocarpus

turbinatus (garjan), Artocurpus chaplasha (chapalish), Syzygium spp. (jam), Dhabanga

grandifolia (bandarhola), Michelia champach (champa), Toona ciliata (toon),

Lagerstromia speciosa (jarul), Gmelina arboria (gamar) etc. Moreover, there are fruit

species, bamboo, cane, climbers, fern, medicinal plants and shrub species such as

Cleodendrum indicum, Mussaenda roseburghii, Melastoma malabatricum etc. Among

the mammals Macaca mulatta (monkey) and Panthera pardus (Indian leopard) are

common, while among the reptiles Ophiophagus hanna (king cobra), Varanus salvator

(monitor lizard) and Varanus bengalensis (Bengal monitor lizard) noteworthy.

Selected 8 land covers: More than 25 land covers were present in Bandarban Soil and

Water Conservation Centre. In the present study 8 land covers were selected to determine

variations in soil properties and other features. The 8 selected land covers were (1)

Mangifera orchard planted in 1995, (2) Syzygium orchard planted in 1995, (3) One year-

old fallow land, (4) Pineapple cultivated area, (5) Bushy land, (6) Natural bamboo forest,

(7) Natural forest, and (8) Deforested land. All the selected sites were situated side by

side on relatively homogenous land, except deforested land. In absence of deforested land

within the centre, one deforested land was selected adjacent to the centre having similar

topography and site conditions. From each site, soil as well as litter samples were

collected and then analyzed in laboratory for the physical and chemical properties.

Besides, vegetation study was also conducted and described for each land use. The staff

working in the centre helped in providing information related to past management of each

land use.

1995 mango orchard: The mango orchard was situated to the north side of Syzygium

orchard covering an area of 2.3 ha. The land possessed moderately very steep (40-46%)

slope from east to west. During planting, fertile top soil and compost at a ratio of 1:1, and

fertilizers like urea, triple super phosphate (TSP) and murate of potash MP were used at

a ratio of 2:2:1 and at a rate of 250 g per pit. Tree canopy covered area on the land was

about 90% with 600 stem density ha-1 with 10% ground coverage. Height of trees was

9.98 m and dbh 17.79 cm. The Surface soil in this orchard was covered by fresh,



partially decomposed litter and humus, but possessed severe to very severe erosion

hazard to the downward slope. The land possesses severe drought in the dry season.

1995 jam orchard: The Syzygium orchard covered 3.3 ha land was situated to the south

side of Mangifera orchard on moderately very steep (40-46%) slope from east to west.

During planting, fertile top soil and compost at a ratio of 1:1, fertilizers like urea, TSP

and MP were also used at a ratio of 2:2:1 at a rate of 250 g per pit as basal dose. The

orchard was covered by fresh, partially and completely decomposed leaf litter. Tree

canopy covered area was about 85% with stem density of 500 ha-1 of 11.96 m height and

19.55 cm dbh. The land possessed 40% ground coverage.

Fallow land: The fallow land covered 4.5 ha land and situated to the south-east side of

meteorological station of the soil conservation center. No trees, herbs, shrubs and bushes

were present on the land but enormous stones without litter present on the soil surface.

This land was previously cultivated with HYV paddy of BR-26 on gently undulating

(15%) land and BR-27 on moderately steep (25%) slope in 2003. The slope direction was

from south to north. Paddy was grown on the hill slope without any sort of land

disturbances like leveling of land, cutting of earth etc. The land experienced severe soil

erosion hazard.

Pineapple cultivated land: This land covering an area of 2.4 ha was planted with

pineapple in January, 2006 situated to the north-eastern side of meteorological station.

During planting of suckers, 2.5 g TSP and 2.5 g MP per plant was applied as basal dozes.

Afterwards before and after rainy seasons urea, TSP and MP were applied at a rate of 2.5

g, 1.5 g and 1.0 g per plant, respectively, This site was located on nearly level to very

steep (35%) medium high hills at an altitude of 153-181 m above MSL. The slope

direction of the land was from south to north. Pineapples were planted along the contour.

Narrow spaced pineapple suckers in the row acted as compact vegetation hedge barrier

and arrested eroded soil material efficiently. Very few grasses with no litter were present

on the land.

Bushy land: The bushy land covered by an area of 1.6 ha was situated to the south of

Syzygium orchard with 44% slope. The site was well-drained. The soil was dark



yellowish brown to strong brown with a pH of 4.23. Very few grasses were present on the

site covered with litter accumulation. Some of the undergrowth species found in the area

were bhat (Clerodendrum viscosum), lajjabati (Mimosa pudica), assamlata (Eupatorium

odoratum), kootumkata (Caeslpinia cristael), tokma (Hyptic suaveolens), taralata

(Mikinia cordata) with a number of vines and medicinal plants.

Natural bamboo forest: This bamboo forest covered 2.5 ha land and situated to the east

side of bushy land. Slope percentage varied from 36% to 46% from west to east. The

naturally bamboo grown site was moderately well-drained. Bamboo covered area was

about 90% with no undergrowth. The number of culms/clump in this site was 32667ha -1

of height 10 m. Presence of fresh and partially decomposed bamboo leaves on the land.

Natural forest: Natural forest covering an area of 5.3 ha was on the northern aspect

situated to the north side of meteorological station. The slope of this forest land was steep

(30-42%) from east to west. The forest was covered by fresh, partially and completely

decomposed leaf litter and well-drained. Undergrowth vegetation consisted of a number

of herbs, shrubs and climbers. Both tree canopy coverage and ground coverage was about

80% and tree stem density of 800 ha-1of various species in the forest. Tree height and dbh

were 18.57 m and 29.43 cm, respectively.

Deforested site: The site deforested long before was irregular with an average slope of

42%. The soil was well-drained. Soil erosion occurred on the land evenly because of

huge disturbances of the villagers and cattle grazing. Undergrowth consisted of a number

of herbs providing 15% ground coverage having no tree species and litter.

3.2 CLEAR FELLED AND BURNING AREA:

3.2.1 Hasanabad block:

Fatikchhari is a natural mixed forest of Dipterocarpus spp. (garjan), Syzygium grande

(dakijam), Michelia champaca (champa), Shorea robusta (sal), Albizia richardiana

(rajkoroi), Swietenia macrophylla (mehogoni), Terminalia arjuna (arjun), Emblica

officinalis (amloki), Terminalia chebula (hortoki), Terminalia belerica (bohera) and

Litsea monopetala (meda) at Hasnabad block, Chittagong North Forest Division.



Natural forest: This site was a patch of 10 year old natural garjan forest on flat hill top at

37 m elevation near Hasnabad Forest Range office. Previously this forest area was under

mixed forest of Dipterocarpus turbinatus (garjan), Syzygium grande (dhaki jam) and

Artocarpus chaplasha (chapalish). Canopy coverage of the patch of natural garjan forest

was 90% with few scattered undergrowth. Undergrowth was mainly of Calamus guruba

(jalibet) and seedlings of Dipterocurpus turbinatus. Forest floor was covered with thick

layer of fresh and partially decomposed litter.

Clear felled area: This clear felled site was 50 m west of natural garjan patch having

similar elevation and topography. Previously clear felled area was covered with garjan,

which felled in 2006. Canopy coverage of clear felled area was 10% with few scattered

undergrowth, mainly of Calamus guruba (jail bet). Litter coverage and thickness at this

area was lower compared to natural forest.

3.2.2 Hyanko block:

Hyanko Forest Block was situated at Chittagong North Forest Division. This contained a

pair of site, representing one plantation and one clear felled area.

Plantation: This plantation was situated at the southern part of the Koila Bazaar under

the Hyanko Block and Beat in Korerhat Forest Range. This was 25 year old garjan

plantation, established in 1982. This site was on middle part of 19% hill slope. Canopy

coverage of site was 90% and undergrowth consisted of Calamus guruba (jalibet),

Melastoma malabathricum (bon tejpata) and different kinds of herbs.

Clear felled area: This was a 2003 clear felled area, 200 m south side of garjan

plantation. Before clear felling 40 year old teak plantation was present there and then

planted with teak, garjan, mahagoni, dhaki jam, champa, chickrassi, arjun, haritaki etc.

This site was on middle of 15% hill slope. This site possessed 60% canopy coverage with

undergrowth mainly of Imperata cylindrica (sungrass), Melastoma malabathricum,

Calamus guruba etc.

3.2.3 Feni block: Feni Forest Block was also in Chittagong North Forest Division. This contained a pair

site, representing one plantation and one clear felled area.



Plantation: This plantation was situated at the southern side of the Bhanga tower under

the Feni block at Korerhat sadar Beat and Range. This was 41 year old Tectona grandis

(teak) plantation and established in 1966. Plantation site was lying on the middle part of

17% hill slope. Coverage of plantation was 60% with Imperata cylindrica (sungrass) as

characteristic undergrowth in the plantation. Other under growth species were bhat,

dhumki etc.

Clear felled area: This was a 2007 clear field area, 70 m west of teak plantation. Before

clear felling of this site, 40 year old teak plantation was there, which felled in 2007. This

site was also on mid hill of 20% slope. Tree canopy coverage at this site was 8% and

undergrowth mainly Imperata cylindrica (sungrass), dhumki and Citrus lemon (lemon).

3.2.4 Ichamati:

The study area for determination of clear felling effects on soil properties was at Ichamati

Range under Chittagong North Forest Division. Ichamoti Forest Range is divided into

three Forest Beats viz. Ichamoti, Bogabil and Nischintapur, covering an area of 2948.76

ha. Sampling sites both at 1956 teak plantation and clear felled area were situated in

Thandachori Forest Block of Ichamoti Beat. Administratively, this site is situated at

Rajanagar Union under Rangunia Upazilla in Chittagong District. Rangunia Upazilla lies

from 22018N to 22038 N latitudes and from 91058 E to 9209 E longitudes. About 70

years back, Rangunia Upazila was rich in forest, consisted of a mixture of many tropical

evergreen and deciduous species occurring in association with bamboo jungle as

undergrowth. Following widespread deforestation in Chittagong Forest Division,

artificial plantation was started in 1949 with Tectona grandis (teak), Dipterocarpus spp.

(garjan), Terminalia chebula (horitaki), Terminalia bellirica (bohera), Terminalia arjuna

(arjun), Lagestroemia speciosa (jarul), Hopea odorata (telsur), and Shorea robusta (sal),

which till now continued.

3.2.5 Chittagong University campus:

Chittagong University campus contained following 3 pair sites for determination of clear

felling effect on carbon storage, which are described below:



Clear felled area with adjacent 14 year mixed plantation: This site contained clear-cut

area and adjacent 14 year old mixed plantation of Garjan, akashmoni and eucalyptus. The

clear-cut area was on eastern aspect situated to the north of Forestry garage, Chittagong

University with the geographical position 22027′890″N and 091047′785″E. The area was

previously covered with 14 year old Akashmoni plantation. It was a moderately steep hill

(18%) like other sites with ground coverage of 40%, scattered covered with creeper,

herbs and grasses etc.

The adjacent mixed plantation of Garjan, Akashmoni and Eucalyptus was 14 year old.

The plantation hill was facing the Southeastern aspect and slope was 25%. The canopy

coverage of the area was 75% with ground coverage of 35% mainly, covered by grass

and herbs mainly by bhat with little or no litter.

Clear felled area with adjacent 16 year mixed plantation: This pair site contained

clear-felled area of 2007 and adjacent 16 year old mixed plantation of Chickrassi

(Chickrassia tebularis) and Jarul (Lagerstroemia speciosa). Geographical position of this

clear-cut site was 22027′939″N and 091047′769″E facing eastern aspect situated to the

South of Paharika housing society, Chittagong University. The area was previously

covered with 14-year-old Akashmoni plantation. It was a moderately steep hill (15%)

with ground coverage of 40%, scatteredly covered by creeper, grasses and herbs mainly

bhat.

The adjacent mixed plantation of chickrassi and jarul was 16 year old. Slope was 20%

and site was facing the eastern aspect. The canopy coverage of the area was 70% with

ground coverage of 45% mainly, covered by climbers, bhat, grass etc. with little or no

litter.

Clear felled area with adjacent 20 year mixed plantation: The clear-cut area was on

northeastern aspect situated to the west of the Nipobon school in Chittagong University

located between 22028′148″N and 091047′612″E. This was clearfelling area of 2007 with

adjacent 12 year old mixed plantation of mahagoni and koroi with similar edaphic

conditions. The area was previously covered with 14-year-old akashmoni plantation. It



was a moderately steep hill (24%) with ground coverage of 50%, covered by scattered

bhat (Clerodendrum viscosum), asamlata (Eupatorium spp.) and grasses.

The adjacent mixed plantation of Mahagoni and Koroi was of 20 years old. Slope and

aspect were similar to clear felling area. The canopy coverage of the area was 75% with

ground coverage of 80% mainly, covered by climbers, grass and herbs mainly bhat

having litter of 2cm depth.

Burning:

Hilly land within the Chittagong University campus is brought under forest through

plantations during the last two decades. On the other hand, people from nearby villages

used to cultivate hills outside campus from long before generation to generation.

Therefore, to investigate effects on soil properties selected forest lands were within the

University campus and burnt land situated adjacent to the campus. On adjacent land of

the Chittagong University campus farmers do cultivation on hilly land after clearing the

forest vegetation consisting of thickets, bamboos and grasses of the past time. Such a

managed land situated to the north-west corner and beside the botanical garden area of

Chittagong University was studied to see the effect of burning on some soil physical and

chemical properties. The pair site representing burnt and no burnt land was as follows:

Burnt area: In the burnt area all the vegetation of the land were slashed in December-

January and after drying burnt in mid February - March, i.e. in pre-monsoon time. Thus,

no tree was present in the burning area except some thickets and grasses.

No burnt land: The vegetation in no burnt area was highly disturbed due to biotic

interference such as human interference, grazing etc. The land contained secondary

vegetation such as thickets, along with a few scattered trees, thatching grasses and some

bamboos.

3.2.6 Fulchari:

This study area for determination of clear felling effects was at Fulchari Beat

and Range, under Cox's Bazar North Forest Division. Fulchari Range had total

area of 3573.66 ha of which Reserved Forest comprises 3505.67 ha and the rest

67.99 ha protected forest. Fulchari Forest Range includes five Forest Beats,



namely Fulchari, Medhakachapia, Khutakhali, Napitkhali and Rajghat.

Administratively, the Fulchari Beat is situated at Chokoria Upazilla in Cox's

Bazar District. The topography of the area is irregular consisting series of

ridges (Das, 1980). Soil in the study area varies from clay to clay loam on level

land and from sandy to coarse sandy on hilly land (Chowdhury, 1969). The

forest area has four main geological formations, namely: Pleistocene, Pliocene,

Mio-Pliocene and Miocene (Balmforth and Howlader, 1988; Mabud, 2001).

The forest area is generally hilly with gentle to steep slopes. Locally sandy

loam on ridges and silty clays in basins occupy small areas having strongly

acid reaction. Some of the higher valley soils are moderately well-drained with

brown, loamy, moderately structured and very strong acid sub-soil (Mabud,

2001). The natural forest is characterized by the presence of dominant species

such as Acacia hybrid, Acacia acuriculiformes, Syzygium spp., and others,

shrub species like Cleodendrum indicum, Mussaenda roseburghii, Melastoma

malabatricum and others. The natural forest habitat found in the study area is

generally poor in quality. Unfortunately, collection of forest products such as

fuel-wood and others by the people residing inside and around the forests and

clearing of forest areas for the cultivation of agricultural crops have been

adversely affecting the quality of vegetation.

3.3 SHIFTING CULTIVATED AREA:

The land area of Chittagong Hill Tracts (CHTs) is 13180 km2 with a population of

1587000 (BBS, 2011) and constitutes about 75% of the total hills of Bangladesh (Khisa,

1997). Administratively, CHTs consist of Rangamati, Khagrachari and Bandarban

district and possess 10% landmass of Bangladesh. This hill tracts region provides biggest

share of forest resources owing second largest reserve forests (322,331 ha or about 24%

of the region). Demographic and environmental conditions are changing rapidly in this

mountainous region. Due to scarcity of suitable land, the traditional slash and burn

farming system, locally known as Jhum cultivation, is becoming unsustainable. This

cultivation system combined with other factors such as over exploitation of the forest is



the cause of increased land degradation, such as soil erosion, nutrient decline and

decreased biodiversity.

Most of the hills in CHTs are of Tertiary age and contain high hill ranges (350 m – >1000

m above MSL). The hills comprise the higher parts of major anticline and possess steep

slope (>40% to over 100%). In the high hill ranges, rocks are semi-consolidated to

consolidated possessing Surma and Tipam formations of Oligocene to Miocene age. In

the hills, rocks are mainly shale, siltstone, sandstone and some conglomerate, and

considerably folded, faulted and uplifted. In the region, the anticlines form the hills and

the synclines form the valleys. The intensity of the folding is greater towards east,

causing higher topographic elevation in the eastern CHTs. Tipam formation has a

thickness of about 1,200 m to 2,500 m and the Surma formation of about 3,500 m to

4,500 m. Surma formation is probably the most important stratigraphic unit in

Bangladesh represented by great thickness and forms the backbone of the eastern hilly

areas of Bangladesh. The hills consist of a series of anti-clinical ridges lying parallel to

one another. The ridges are aligned approximately north-northwest to south-southeast.

The three major rivers: the Karnafuli, the Sangu and the Matamuhuri along with their

tributaries form the drainage system in this mountainous watershed with a total

catchments area of approximately 1400 km2. The drainage of the Karnafuli river has been

greatly affected by the construction of Kaptai dam in 1962 for hydro-electricity

generation, submerging about 922 km2 of the Karnafuli river system and converted into

an artificial lake.

The river Karnafuli divides this upland area into nearly two equal parts. In the northern

part of the river 5 major hill ranges separated the valley of Feni, Chengi, Maini,

Gangaram, Kassalong and Sajek Rivers, while in the southern part five main ranges

separated the valley of Bakhhali, Matamori, Sangu, Ringkheong and Thega Rivers. These

river-valleys are mostly narrow with a wide belt of hills of varied elevation on both sides.

The highest peak of Bangladesh is situated in Bandarban, named as Tajindong (1230 m).

All hill ranges are very steep with slope> 400. The eastern side of the ranges is steeper

than the west. This steepness contributes greatly to the serious problems of erosion. The

mountain ranges of the CHTs are characterized by a huge network of trellis and dendrite



drainage ending into the Bay of Bengal. Within CHTs the Karnafuli has several important

tributaries, of which Chengi, Kasalong and Rainkhiang are the main ones. The hill ranges

and the river valleys are generally longitudinally aligned. Four ranges, with an average

elevation of 330 m from west to east are Phoromain, Dolajeri, Bhuachhari and Barkal

with highest elevation of 463 m, 429 m, 611 m and 735 m, respectively. Seven main

mountain ranges from west to east namely Muranja, Wayla, Chimbook, Batimain, Politai,

Saichal-Mowdok and Saichal are situated to the South of the Karnafuli River with highest

peaks between 526 m and 1,003m. Saichal range contains the highest peaks of

Bangladesh situated on the border with Myanmar. Some hill ranges also contain

important geological structures such as Semutang, Sitapahar, Matamuhuri and Bandarban

anticlines to form excellent structural traps for natural gas accumulation. Rainkhiangkine

and Bagakine natural lakes and Kaptai artificial lake are situated in CHTs.

Under shifting cultivated land topsoil is from 0- 20 cm, subsoil from 20 – 50 cm and

substratum from 50 - 80 cm with variable depth from place to place, particularly hill

position such as, hill top, middle and bottom. The substratum occurs at a variable depth.

The texture varies widely from sandy clay loam to clay, depending on the type of parent

rocks. Soils at all depth are well drained formed on sandstones, siltstones and shale parent

materials. Under forest vegetation the color of the topsoil becomes dark yellowish brown

to very dark grey and in the substratum becomes strong brown. Under shifting cultivated

land the color of the topsoil becomes dark olive brown to brown, in subsoil olive yellow

and in the substratum yellowish brown. Under forest topsoil is very strongly acid (pH

4.6) and under shifting cultivated soil very strongly acid to strongly acid (pH 3.98 – 4.88)

with slight increase in pH with depth. In surface soil C/N ratio ranges from 10 – 14 and in

the substratum 6 - 9. In the surface soil available P ranges from 1.6 – 12 mg/kg soil,

available Ca from 2.3 - 6.5 mg/kg soil, available Mg from 0.5 – 1.6 mg/kg soil with

increase in subsoil and decrease in substratum.

The climate of this mountainous watershed is characterized by tropical monsoon with

mean annual rainfall 282 cm in Kaptai and 257 cm Rangamati (UNEP, 2001). This area

experiences long dry season from October to May and monsoon wet season from June to

September. Cyclones are frequent during May to October. Over 80% of the rainfall



occurs between May and September. The dry and cool season is from November to

March when temperatures range from 80C to 150C, pre-monsoon season from April-May

very hot and sunny when temperatures range from 240C to 350C, and monsoon season

from June to October warm, cloudy and wet when temperatures range from 200C to 360C.

The relative humidity ranges between 65% in the dry season and 90% during monsoon.

In recent years, the weather pattern has been erratic, with a reduction of the cool, dry

season and late rainy season, which may be beginning of long-term changes due to global

warming caused by greenhouse gases.

The annual stream flows of the Karnafully, the Sangu and the Matamuhuri rivers are 3.67

million hectare meter, 0.66 million hectare meter, and 0.44 million hectare meter,

respectively. During the driest month in March, about 92% flow of the Karnafuli River is

coming from the Kaptai reservoir.

In CHTs only 6% land suitable for intensive production of agriculture (Khisa, 1997).

Within CHTs Unclassed State Forest lands occupy 10,121 km2, Kaptai Lake and other

water area 535 km2 and the rest 2,581 km2 under reserved forest. In CHTs only 3-5%

lands have few limitations for crop production occupying valleys of the region used for

variety of field crops, 20% of the lands possess moderate to severe limitations to crop

production and suitable for horticulture and the rest 75% vulnerable hill slopes of steep to

excessively steep have severe limitations for general crop production. The major land

uses in CHTs are shifting cultivation, horticulture crops, tea, rubber, yam and ginger on

different parts of the hill slope without considering soil loss in many cases (Shoaib,

1997). Most parts of hill are under teak plantation and managed by Bangladesh Forest

Department.

Previously population pressure was confined only in the lowland watershed and at

present population density is increasing in the hilly region at alarming rate because of

migration of people from plain land in scarcity of traditional agricultural land. Population

in CHTs in 1872 was 0.063 million and in 1998 became 1.1 million (Khisa, 1997).

During the period from 1872 to1991, indigenous population rose from 0.062 million to

0.501 million, while non indigenous from 0.002 million to 0.473 million.



3.3.1 Kark Mohajon Para:

Shifting cultivated soil:

Ready for jhumming: Kark Mohajon Para is located on Khagrachari to Diginala Road

under 26 No. Perachara Mouja. This site is about 11 km away from Khagrachari Sadar

Upazilla and to the west side of Chiakhola. This area was on 28% hill slope. On this hill

3 soil profiles were dug on hill top near Chitakhola, an important feature for locating the

place.

1 year old jhum cultivated area: One soil profile was dug in 1 year old rubber

plantation where paddy grown as jhum crop last year. During soil sampling paddy straw

was present on soil surface of one year rubber plantation. This site was to the south east

of teak plantation. Above this sampling site 13-year old rubber plantation present on hill

top and hill slope.

Forest soil:

8 year old teak plantation: The 8-year old teak plantation was situated adjacent to

shifting cultivated site to the east of ChitaKhola. The hill had 40% slope on the top

portion, but lower portion >80% on southern aspect. In teak plantation no undergrowth

was present. Shifting cultivation was done at this teak plantation area previously at least

more than 3 times. Two soil profiles were dug on hill top in this 8 year old teak

plantation. Earthworm activities were frequent in this profile.

4 year old gamar plantation: Two profiles slightly away from teak plantation were dug

in four year old rubber plantation on bottom part of hill slope.

3.3.2 Simina Para:

Following two land covers, one representing shifting cultivated land and the other by a

patch of natural forest, were studied in this area:

Ready for jhum cultivation: The area is located on Khagrachari to Dighinala road at

Simina Para, which about 15km away from Khagrachari Sadar Upazilla with a

geographical position of 23°12.041'N and 92°01.967'E. The area was ready for jhum



cultivation during sampling date on 25 April 2007. Three profiles were dug in this

jhuming area.

Forest land: This hill was covered with different vegetation types on different parts of

the slope. Vegetation on valley consisted of kalichari (Gigantochloa andamanica) 50%,

Neohouzeana dullooa (dolu) 20%, Melocanna baccifera (muli) 30%. Vegetation on hill

slope consisted of Syzygium fruticosum (puti jam), Aphanamixis polystachyd (rahunia),

Abroma augusta (ulot kambal) toprin gach, which is used by bird as food materials,

Qurcus spicata (batna), Artocarpus chaplasaha (chapalish), Tectona grandis (segun),

Alstonia scholaris (chatim) etc.

3.3.3 Milan Karbari Para:

Milan Karbari Para is located beside Khagrachari to Dighinala Road at Milan Karbari

Para in Khagrachari Sadar Upazilla with a geographical position of 23°12.250'N and

92°01.749'E. This is a hilly area with an elevation of 201 m. Soil samplings were done

from profiles of the following described pair site:

Ready for shifting cultivation: This area was brought under banana plantation after

slashing and burning. Previously jhum was done at this site four times. Now, this area

was brought under rubber plantation and banana also planted in places.

Forest land: This profile was on flat hill top, in a patch of bush. In this area jhum

cultivation was done 20 year ago, but during soil sampling the area covered by different

species mainly of Mecarenga scandea, Melastoma malabalthricum Linn., sulakhari etc.

3.3.4 Alutila:

Demonstration plot on Sloping Agricultural Land Technology (SALT) of Chittagong Hill

Tract Development Board (CHTBD) was located at Alutila under Matiranga upazila of

the Khagrachari district. Chittagong Hill Tracts Development Board (CHTDB)

established this farm in July 1993 as a pilot project under SALT. It was one of the

programmes of International Centre of Integrated Mountain Development (ICIMOD) at

Kathmundu, Nepal. The total project area was about 20.61 ha, of which 18.94 ha for the

SALT demonstration farm and 1.67 ha for the intended farmers (SRDI, 1991).



Soil samples from the site were collected on May, 2003. The project manager of

Chittagong Hill Tracts Development Board (CHTBD) helped to select four different hill

farming sites including modern and traditional farming system to make a comparison of

jhumming effects on soil properties. The description of each of these sites is given below:

SALT abandoned area where no jhumming done before: This site situated on the east

aspect, was one of the SALT demonstration plots which brought under SALT in 1994. In

this plot no jhumming and any other form of cultivation was done before. Here, the soil

surface was covered with litter fully (100%). Naturally coming tree species were

Kanchan (Bauhinia spp) of height 6.1 m, Rubber (Hevea brasiliensis) of height 19.14 m

and Bogamedula (Indigofera spp) of height 1.5 m. This plot was also covered fully

(100%) by the tree species and 50% land with herbs. This site having no jhumming

before acted as control over the other three sites.

8 year old SALT adopted site, but abandoned in 2002: This SALT demonstration plot

facing to the west aspect was under shifting cultivation until 1993 and brought under

SALT in 1994. This land elapsed 8 years under modern salt technology upto 2002, after

which left as abundant land from SALT cultivation. During the sampling on May, 2003

the land was covered with annual crop, horticultural and forest tree species along with

100% grass coverage. Horticultural crops included guava (Psidium guajava), litchi

(Litchi chinensis), lebu (Citrus aurantifolia) and other fruit tree species. The main tree

species in this plot was sada koroi (Albizia procera) of about 11 m height. However, this

land was abandoned in 2002 from SALT. That means, this plot was not managed by

SALT after 2002 due to completion of project period.

Land ready for current jhumming: This site was outside the SALT demonstration plot.

During sampling on 26 May 2003, the land was ready for jhumming and supposed to sow

seeds in June of the same year. The site faces to the east aspect with 55% hill slope. Soil

sampling was done on middle part of this hill slope. It was a burnt area, ready for shifting

cultivation after necessary soil work having no litter, herbs, shrubs and trees. The site was

kept fallow for three years from 2000 to 2003.



Jhumming done in 2002: This SALT demonstration plot was fallow for the last one year

situated on the west aspect of a steep hill slope. The site was covered with vegetation

like, many flowering plants, few sungrasses, vegetables and naturally grown tree species.

Vegetation included banana (Musa sapientum), Eupatorium odoratum and Mikania

scandans and naturally grown tree species were Jangli begun (Solanum melongena),

Dumur (Ficus roxburghii), Cycas ( Pnetum ula), Gamar (Gmelina arborea) and Koroi

(Albizia spp). Very few Koroi trees were also present on this site. This land would be

kept fallow for another two years after which land would be used for jhum cultivation

again.

3.3.5 Sukurchhari

Sukurchari under Kutukchari Forest Range is located beside Rangamati-Manikchari-

Mohalchari-Khagrachori Road, about 7 km from Manikchari. Reconnaissance survey was

first conducted at Sukurchari to find out pair land having shifting cultivated area of

different years and natural vegetated land side by side. Survey showed that such pair site

was absent in the area. For this reason following five different hills were selected at

Sukurchari on north-west aspect, situated on west side only of the road.

Shifting cultivated land: This site was one year old shifting cultivated land on medium

high hill on eastern aspect at geographical position of 22040′522″N and 092007′235″E.

Paddy residues of the last year was still existed on the land with 75% grass vegetation

and 15% ground coverage, mostly of asamlata of 80% (coverage cm in height).

Mixed plantation: Adjacent to this shifting cultivated area mixed plantation of litchi,

jackfruit, gamar, teak, supari and jam were present on upper part of the medium high hill

at 22041′545″N and 92006′242″E geographical position. Tree canopy coverage of this

plantation was 80% with full ground coverage and 4 cm litter depth.

3.3.6 Muralipara:

Murali Para is located beside Gagra-Kaptai Road, Phulgaji Range under Jhum control

division at Mulari Para under 100 No. Wagga Mouja, Kaptai, about 3 km from Gagra.



One family has been residing permanently on lower part of hill slope at this shifting

cultivated area and used to do shifting cultivation on the hills. Here, the whole hilly area

was under shifting cultivation rotationally. On shifting cultivated land on hill slope

having 65% gradient on western aspect major crops were turmeric (Curcuma longa),

zinger (Zingiber officinale), sajina (Moringa oleifera), arum (Abrus precatorius) and

banana (Musa paradisiaca).

Shifting cultivated land: This site was 2 year old slashed and burnt area, situated at

Mulari para on the way to Gagra, Kaptai Road, under Phulgaji Range and Jhum Control

Division. In this shifting cultivated area vegetation was wild banana on medium high hill

facing the eastern direction at geographical position of 22034′942″N and 092006′229″E.

Sungrass was the only ground vegetation in this land with 15% coverage.

Mixed plantation: The area was a patch of forest, adjacent to the shifting cultivated area.

The land was under 25 year old jackfruit, blackberry and mango tree plantation along

with bamboo and sun grass (Imperata cylidrica) as undergrowth. On this hill, tree canopy

coverage was 30% and undergrowth coverage 70%.

3.3.7 Burburichhara

Shifting cultivated land: This site was located in Barkal upazila of Rangamati district

with the geographical position of 22043′703″N and 92021′219″E. This was a hilly area

having 100 % slope with an elevation of 364m on the north-west aspect. Shifting

cultivated crops were paddy, turmeric, gamar and banana with the presence of some

grasses in patches.

Mixed plantation: Adjacent land was a mixed plantation of koroi, gamar, tula, and teak

along with bamboo, sungrass, baruna, wild banana etc. This site was on steep (100%)

high hill on north-west aspect at 22043′699″N and 92021′150″E geographical position. In

this plantation tree canopy coverage was 98% and undergrowth coverage 80% having 4

cm forest floor.

3.3.8 Maijchhari



Shifting cultivated land: Maichchari shifting cultivated area was located in Barkal

upazila of Rangamati district at geographical position of 22043′612″N and 92019′695″E.

This was a hilly area having 80 % slope facing the south-western aspect. In this shifting

cultivated area crops were paddy, turmeric and banana.

Mixed plantation: The adjacent mixed plantation was of teak, jam, vadi, jarul and hijal

on medium high hill of 90% slope on south-west aspect at 22043′606″N and 92019′745″E

geographical position. Tree canopy coverage in this plantation was 70% with 30%

undergrowth.

3.3.9 Longadu:

Shifting cultivated land: The shifting cultivated land in this pair site was situated at

Longadu upazila to the north-western part of Rangamati district at geographical position

220 50′614″ N and 92017′417″ E on steep high hill facing south eastern aspect. Shifting

cultivated crops were paddy, banana, turmeric etc. with no undergrowth.

Mixed plantation: Adjacent mixed plantation of teak and gamar was on steep high hill

(100% slope) on south–eastern aspect at 22045′512″ N and 92018′545″ E geographical

position. Tree canopy coverage on this hill was 70% with 40% ground coverage, mostly

of herbs with very little or no litter.

3.3.10 Betchara:

Betchara is located on Bandarban-Chimbuk Road at 314 No. Soalok Mauza, 9 miles

away from Bandarban Sadar district. The site is under Betchara Forest Range of

Bandarban Forest Division with geographical position of 22º07′45″ N and 92º13′42″E.

This is a hilly area having 10-24 % slope and an elevation of 364 m on the north-west

aspect. Soil sampling was done on first week of February 2007 at upper part of the slope.

Reconnaissance survey was conducted first to find out pair lands having jhuming area of

different years and natural forest/ natural vegetated areas side by side. In absence of

natural forest and shifting cultivated area on the same hill, soil samplings were done from

three different hills having slashed area, 1-year shifting cultivated area and forest area on

three separate hills.



Shifting cultivated soil: Reconnaissance survey was conducted first to find out pair lands

having jhuming area of different years and natural forest/ natural vegetated areas side by

side. Betchara is located on Bandarban-Chimbuk Road at 314 No. Soalok Mauza, 15 km

away from Bandarban Sadar district under Betchara Forest Range of Bandarban Forest

Division with the geographical position of 22°07.45' N and 92° 13.42' E by the side of

Bandarban Chimbuk Road. At Betchara no natural forest was found and comparison

made between slashed area and one year jhum cultivated area. Here, three profiles were

studied in slashed area on three hill positions - top, middle and bottom, and 3 profiles on

1 year old jhum cultivated area on different hill positions. Site descriptions of slashed and

1 year shifting cultivated are given below:

Slashed area: This was a three year old shifting cultivated area, which slashed again for

jumming. This was a round topped hill having 10-24 % slope on the north-west aspect.

Slashing is the first stage of shifting cultivation in which all the previous vegetation on

the land is cut down and allowed to dry, after which land burnt. The vegetation during

soil sampling was consisted of only a few bamboo, banana, papaya etc. On this hill three

profiles were dug - one on the hill top, second one on the middle part of the hill and third

one on hill bottom.

One year shifting cultivated area: One year old shifting cultivated area was on

separate several hills slightly away from slashing hill at 314 No. Soulok Mouza, 15 km

from Bandarban Sadar. Hill slope was 12% on north-west aspect and around this hill,

steep hill slope present. Soil profiles were dug on this hill at top, middle and bottom

part.

Forest soil: This site was located on a different hill near to shifting cultivated site with a

geographical position of 22°07' 19 N and 099°13'41 E. Slope at hill top was 16% with an

elevation of 350 m and at middle to lower part 26% slope on north-west aspect. Forest

vegetation was mainly of bamboo with few shrubs and climbers.

3.3.11 Tarasa:

Shifting cultivated soil with bushy land: Khanshama para, Tarasa is located on

Bandarban to Ruangchari Road under Tarasa Forest Range of Bandarban Forest Division,



with a geographical position of 22°12.20' N and 92°15.38' E. This was a hilly area with a

slope of 12 % on north-west aspect. This was a long hill, having absence of any forest,

for which comparison done with naturally grown sporadic bushes. On this hill, three

samples were collected from shifting cultivated area and three from bushy area at a depth

of 0-6 cm. Three soil samples from each land use are mixed together to make a composite

sample. The area was jhum cultivated one year before.

3.3.12 Thanchi:

Selection of soil sampling sites: Two paired sites, one on 55% slope and the other on

35% slope, were selected in orange growing area at Bolipara under Thanchi Upazilla. In

each pair, one part represented orange orchard and the other forests, being adjacently

located on similar slope to avoid initial variation in soil properties between the two, due

to topographic differences. To provide clear idea description of two paired sites is given

below:

On 55% slope:

Orange orchard: This hill slope faces eastern aspect. Northern part of this slope was

under orange (Citrus aurantaneum) orchard and the southern part under forest cover.

Orchard floor was covered by orange (Citrus auruntaneum) trees fully (100%) along with

herbs as undergrowth. The undergrowth comprised of various grasses including lojjaboti

(Mimosa spp.). The mean height of the orchard was 3.5 m with an average diameter of

4.7 cm planted with a spacing of about 2.5 m × 2.5 m. Other naturally growing species in

the orchard was banana (Musa sapientum). The orchard was subjected to partial weeding

which included shrub cutting and the land possessed black colored top soil with

earthworm activities.

Forest land: On this slope, forested area was fully (100%) covered by herbs, shrubs and

bushes. In absence of large trees the land lacked abundance of litter. This forest land was

subjected to severe erosion. The naturally growing shrubs were ashamlota (Eupatorium

odoratum) and lantana (Lantana camera) with an average height of 1.20 m.



On 35% slope:

Orange orchard: The site faces eastern aspect of the hill. Orchard floor was covered by

orange (Citrus auruntaneum) trees (100%) along with herbs as undergrowth. The

undergrowth comprised of various types of grasses including lojjaboti (Mimosa spp.),

lantana (Lantana camera) etc. The height of the orchard was 3.1 m with an average

diameter of each tree 3.9 cm planted with a spacing of 2.5 m × 2.5 m. Other conditions in

this orchard were similar to previously described orchard grown on 55% slope.

Forest land: This part containing forests was also covered by herbs, shrubs, bushes along

with a few trees, which were dispersed over the area and the forest floor without litter.

The naturally growing species were ashamlota (Eupatorium odoratum), lantana (Lantana

camera), lojjaboti (Mimosa spp.), koroi (Albizia procera), dumur (Ficus spp.) etc. The

average height of shrubs was 1.25 m and of Koroi (Albizia procera) tree 6.35 m and

Dumur (Ficus spp.) 3.10 m. Similar to previous forest land (on 55% slope) this part was

also eroded.

3.3.13 Bandarban Sadar:

The study was done in Bandarban hill district of Bangladesh where local people practice

shifting for their livelihood. To select representative study sites, a preliminary survey

done in the shifting cultivated areas and its adjacent natural forest of Bandarban Sadar

Upazila. During the preliminary survey local tribal people and FD officials were

interviewed to find out the study sites based on years of shifting cultivation practices and

presence of natural vegetation adjacent to it. Thus, three pair lands were selected namely

1 year, 2 year and 3 year of shifting practices, respectively, and their adjacent natural

forest in Bandarban hill district. A brief description of the three pair lands is given below:

1 year shifting cultivated area with adjacent natural forest: This site was situated on

the middle position of a hill slope at Na-mile village under Bandarban Sadar Upazila. The

average slope was about 28 %. In this site shifting cultivation was done 1 year before.

The tree species of shifting cultivation included gamar, segun, and goiree, covered 45 %

of the land by crown.



Natural forest was situated adjacent to the shifting site. Bamboo, banana, gamar, siyez, sil

koroi, goda, dakudum, banlata and other unknown trees, shrubs and herbs were present in

the natural forest. Canopy coverage of the trees was 100 %, ground vegetation occupied

70 %, and grasses occupied 20 % of the total area. Presence of litter coverage was 40 %

of the total area.


the middle position of a hill slope at Shoalok village under Bandarban Sadar Upazila. The

average slope was about 35 %. In this site shifting cultivation was done 2 years before.

The crops of shifting cultivation included paddy, marfa, papya, pumpkin, banana etc.

During soil sampling in shifting cultivation had no vegetation coverage.

Natural forest was situated adjacent to the shifting site. Bamboo and other unknown trees,

shrubs and herbs were present in the natural forest. Canopy coverage of the trees was 90

%, ground vegetation occupied 58 %, and grasses occupied 10 % of the total area.

Presence of litter coverage was 30 % of the total area.


the middle position of a hill slope at Aat-mile village under Bandarban Sadar Upazila.

The average slope was about 34 %. The shifting site was jhumed 3 years before. Long

period and short period crops were found in shifting site. The crops of shifting cultivation

included paddy, sesame, papya, cotton, maize, jack fruit etc. however underground

coverage 50 %.

Natural forest: Natural forest was situated adjacent to the shifting site. Bamboo, konak,

goda, seuli, sil-koroi, banana and other unknown trees, shrubs and herbs were present in

the natural forest. Canopy coverage of the trees was 100 %, ground vegetation occupied

75 %, and grasses occupied 30 % of the total area. Presence of litter coverage was 35 %

of the total area.

3.4 Soil sampling: For determination of bulk density, 3 undisturbed soil cores or more in

some places were collected in the field from 0 – 5 cm depth by pre-weighed cores. Cores

were driven vertically into soil using wooden hammer. The cores were then carefully dug

out using a sharp knife and excess soil at both ends removed. Then both the ends of the

cores were wrapped with two small pieces of cloths and rubber bands, and carried in a



labeled plastic bag to the laboratory for subsequent analysis. The field moist soil cores

then weighted, allowed drying in an oven 1050C for 8 hours, cooled in a desiccators and

reweighed. Both the field moist and oven dry weights of the cores were divided by the

volume of each core (100 cm3) to determine wet and dry bulk density, respectively.

3.5 Determination of organic carbon in soil

For the determination organic carbon in soil, washed silica crucibles were dried in oven

at 1050 C for 30 minutes and cooled in desiccators and then weight were taken. Dried

soils were grind by pistol and then exactly 5g of grind soils were kept in silica crucibles

and weighted by an electric balance. The crucibles with soils were then transferred to an

electric muffle furnace for igniting at 8500 C for one and half an hour. Then crucibles

with soils were cooled in a desiccators and reweighted to determine the percent loss of

ignition (LOI%)

LOI was expressed relative to the weight of oven dry soil and % of moisture relative to

the weight of field moist soil. Percentage of LOI was calculated as follows:

LOI (%) = w1 / w2 × 100

w1 = loss in weight and

w2 = weight of oven dry soil

Percentage of carbon calculated from the following relationship (Hoque and Alam, 2005)

Organic carbon (%) = 0.476 × (% LOI – 18)

3.6 Calculation of C storage in soil:

Organic carbon concentration of plantation area in 0-20 cm soil depth was 2.67% and for

20-30 cm soil depth 3.30%. From these values carbon storage were calculated as follows:

i) For 0-20 cm soil depth:

1 ha soil with 15 cm depth weighs 2×106 kg



1 ha soil with 20 cm depth weighs

=2.67×106 kg

Now for, Organic carbon = 2.67%

That means, 100 kg soil contains 2.67 kg organic C

Therefore,1.6×106 kg soil contains organic C per ha

= ton organic C per ha

= 71.29 t/ha

ii) For 20-30 cm soil depth:

1 ha soil with 15 cm depth weighs 2×106 kg

1 ha soil with 10 cm depth weigh7s

=1.33×106 kg

Now for, Organic carbon = 3.30%

That means, 100 kg soil contains 3.30 kg organic C

Therefore, 1.33×106 kg soil contains organic C per ha

= t/ha

= 43.89 t/ha

Now, organic C content for 0-30 cm will be = (71.29+43.89) t/ha



= 115.18 t/ha

Thus, the amount of organic carbon was calculated from the following relationship for

the other soil samples:

ha

3.7 Calculation of CO2 sequestered in a standing tree:

Total green weight of a tree:

For trees with dbh < 11 inches

W = 0.25D2H (Richard, 1992)

For trees with dbh >= 11inches

W = 0.15D2H (Richard, 1992)

W = Weight of the tree in pounds

dbh = diameter at breast height (in inches)

H = Height (in feet) up to top of the tree

Depending on the species, the coefficient 0.25 is variable for dbh >11. D2 and H could be

raised to exponents just above or below 1. However, these two equations could be seen

as an “average” for all the species.

The root system weighs about 20% as much as the above-ground weight of the tree.

Therefore, to determine the total green weight of the tree, multiply the above-ground

weight of the tree by 120%.

Determination of dry weight of the tree: All species of the tree is contained 72.5% dry

matter or 27.5% moisture. To determine the dry weight of the tree, multiply the weight of

the tree by 72.5%.



Determination of C weight in tree: To determine the weight of carbon in the tree,

multiply the dry weight of the tree by 50%. Average C content is generally 50% of the

total volume of tree.

Determination of weight of CO2 sequestered in tree: CO2 is composed of one molecule

of C and 2 molecules of oxygen.

The atomic weight of C is 12.001115.

The atomic weight of O2 is 15.9994.

The weight of CO2 is C+2*O=43.999915.

The ratio of CO2 to C is 43.999915/12.001115=3.6663.

Therefore, to determine the weight of carbon dioxide sequestered in the tree, multiply the

weight of carbon in the tree by 3.6663.

3.8 Calculation of CO2 production (IPCC, 2001)

CO2= 12+ (16 x 2)

=44

12 t C produces 44 t CO2

So, 15.2475 t C produces (44 x15.2475)/12

= 55.9075 CO2ha-1

This study has been done in continuation of the works done by several authors (viz. Miah

et al, 2010; Haque et al., 2012; Haque and Karmakar, 2009 and Biswas et al., 2011 ) on

upland watershed in Bangladesh on several aspects of soil and vegetation, but they did

not work on C-sequestration in soil and forest vegetation. In this thesis, therefore, study

has been done on the effects of several human induced activities such as deforestation,

clear felling and shifting cultivation on C-sequestration in soil and forest vegetation of

Chittagong and CHTs regions.


