Assessment of Natural Regeneration Status and Diversity of Tree Species in the Biodiversity Conservation Areas of Northeastern Bangladesh

Abstract

A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (part of Sylhet Forest Division) to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic species. Data was collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots of 2m  2m in size and from 5 different habitat types namely; forest, roadside, homestead (surrounding forest dwellers house), fallow land and others (canals, streams and tea gardens side) represents a total of 55 regenerating species under belonging to 28 families with Khadimangar National Park having the highest number of species (43 species). Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed by roadside (23 species). Total 15 exotic species among 9 families were recorded and 40 indigenous species under 24 families. For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-winner diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance was found in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the country.

Full text

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Journal of Forestry Research (2011) 22(4): 551−559
DOI 10.1007/s11676-011-0198-0




Assessment of natural regeneration status and diversity of tree species
in the biodiversity conservation areas of Northeastern Bangladesh


Md. Habibur Rahman • Md. Abu Sayed Arfin Khan • Bishwajit Roy • Most. Jannatul Fardusi




Received: 2010-11-10 Accepted: 2011-02-09
© Northeast Forestry University and Springer-Verlag Berlin Heidelberg 2011

Abstract : A study was conducted at two-biodiversity conservation areas
of Northeastern Bangladesh (a part of Sylhet Forest Division) to assess
the species composition, diversity and density of natural regeneration of
tree species both indigenous and exotic species. Data were collected by
stratified random quadrate method during January 2010 to July 2010.
Totally 200 circular plots of 2 m×2 m in size had 5 different habitat types
of plants namely; forest, roadside, homestead (surrounding forest
dwellers house), fallow land and others (canals, streams and tea gardens
side), which included a total of 55 regenerating species belonging to 28
families. Meliaceae is the dominant family and shows the highest family
importance value (26.3), having six species, followed by Moraceae
(24.24). Among the five habitat types, forest (43 species) possess the
highest number of species, followed by roadside (23 species). Total 15
exotic species among 9 families and 40 indigenous species with 24 fami-
lies were recorded. For exotic species, Tectona grandis possess the high-
est relative density (11.7%) and relative frequency (10.5%); Senna sia-
mea had highest relative abundance (7.83%). In case of indigenous spe-
cies, Chickrassia tabularis possess the highest relative density (4.23%)
and relative frequency (4%); Dipterocarpus turbinatus had the highest
relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia
tabularis (10.8) had the highest IVI for exotic and indigenous species
respectively. Different diversity indices such as Shanon-Winner diversity
index, species diversity index, species richness index, species evenness
index, Simpson index and species dominance index, etc. were applied to
quantify definite diversity. The regeneration of species associated with
low levels of disturbance was in the exotic species. Study suggests that
proper protection from human disturbances and scientific management of

The online version is available at http:// www.springerlink.com
Md. Habibur Rahman1 • Md. Abu Sayed Arfin Khan1,2 • Bishwajit
Roy1( ) • Most. Jannatul Fardusi1
1 Department of Forestry and Environmental Science, School of Agricul-
ture and Mineral Sciences, Shahjalal University of Science and Tech-
nology, Sylhet-3114, Bangladesh; 2 Department of Disturbance Ecology,
University of Bayreuth, Bayreuth, Germany.
Email: ahir_sust@yahoo.com
Responsible editor: Zhu Hong

natural regeneration of two-study forests may lead a rich biodiversity site
in the country.
Keywords: biodiversity; exotic species; family importance value;
indigenous species; quantitative characters


Introduction

The nature of forest communities depends on the ecological
characteristics in sites, species diversity and regeneration status
of species. Micro-environmental factors vary with seasonal
changes, which affect the trees growth stage i.e. seedling, sapling,
coppice, and young trees that maintain the population structure
(Khumbongmayun et al. 2006). Natural regeneration is essential
for preservation and maintenance of biodiversity. Depending on
management objectives, it is important to maintain the process of
forest renewal by appropriate natural and artificial regeneration.
The clear felling accelerates loss of seedlings and saplings as
well as disturbs the natural condition of the natural forests and
hence the ecosystem (Haque et al. 1988). Knowledge about the
pattern of natural regeneration is important to answer the basic
question of forest management (Hossain et al. 1999).
Bangladesh vegetation is a part of the Indo-Myanmar region,
which is one of the ten global hot spot areas for biodiversity,
with 7 000 endemic plant species (Mittermeier et al. 1998) and
rich biological diversity, due to its unique geo-physical location
(Hossain 2001; Barua et al. 2001; Chowdhury 2001; Nishat et al.
2002). Muhammed et al. (2008a) mentioned that forests in Bang-
ladesh are deteriorating at an alarming rate due to various socio-
economic threats, biotic pressures and competing land uses. The
high degree of dependency that many people have on the forests
for their livelihoods has resulted in depletion of natural resources
and degradation of forest ecosystems countrywide (Muhammed
et al. 2008b). A few researchers (Hossain 2005; Khan et al. 2007;
Mukul 2007; Mukul et al. 2008; Chowdhury et al. 2010), esti-
mated that the total amount of forest cover of Bangladesh is
nearly about 2.53×106 ha, representing approximately 17.5% of
total surface area of the country. According to estimate by FAO
(2007), the total growing stock of Bangladesh’s forests is 30×106
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552
m3 and the total biomass 63×106 tons. However, in 2008, the
area of total forest land of Bangladesh from Bangladesh Forest
Department is 2.52×106 ha (BFD 2008). Rahman et al. (2000)
and Hossain (2001) found that the depletion of native species
was also accelerating at an alarming rate through the rapid loss
and degradation of forests in Bangladesh.
For conservation and management of tropical plant diversity
across the biodiversity conservation areas, the information on
plant diversity is considered as necessary because of its potential
usefulness and implications (Kadavul et al. 1999). Many re-
searchers (Pritts et al. 1983; Saxena et al. 1984; Khan et al. 1987;
Ashton and Hall 1992; Cao et al. 1996; Gunatilleke et al. 2001;
Uma 2001) have carried out various studies on population struc-
ture and regeneration status but these studies were limited in
different forest ecosystems in Bangladesh. Thus, the aim of this
study was to assess the natural regeneration composition, status
and diversity of tree species in two biodiversity conservation
areas namely Khadimnagar National Park and Tilagaor Eco-Park
of Northeastern Bangladesh. In both the study sites, the ground is
covered with herbs, ferns, bamboo, and rattan. Regeneration is
occurring mainly through dispersed seeds from the forest.


Materials and methods

Study sites

The study was conducted in and around biodiversity conserva-
tion areas namely, Khadimnagar National Park (KNP) and Tila-
gaor Eco-Park (TGEP). These areas were selected purposively
considering their unique geo-physical features in biological di-
versity. KNP (N 24º56'−24º58' and E 91º55'−91º59') and TGEP
(N 23º55'−25º14' and E 90º55'−92º31') are located at North Syl-
het Range-1 in Sylhet Forest Division under tropical evergreen
and semi-evergreen bio-geographic zone. KNP was declared as
National Park in 2006, which was formerly known as Khadim-
nagar Reserve Forest. Total area of KNP is 679 ha, surrounded
by three tea gardens, and submerged with several watersheds
locally known as “chara”. TGEP was declared as Eco-Park in
2006 with a total area of 45.35 ha. The hills of these areas are
generally low and gently sloping. Soil ranges from clay loams to
pale brown (acidic) clay loams on the hills. The tropical mon-
soon climate prevails in the area with an average maximum tem-
perature of 30.7 °C and average minimum temperature of 18.9°C.
The average annual rainfall is 3931mm, most of which falls be-
tween June-September (BBS/UNDP 2005). The forest areas are
undulating with slopes and hillocks, locally called tilla. The
study forests are semi-deciduous tropical forest type.

Methods

The present study was carried out from January 2010 to July,
2010. A stratified random quadrate method was used to deter-
mine the regeneration status of the tree species of KNP and
TGEP of Northeastern region, Bangladesh. Sample plots in the
study areas were selected from five different habitats namely;
forest, roadside, homestead (surrounding forest dwellers house),
fallow land and others (canals, streams and tea gardens side).
Total 200 sample plots (100 from KNP and 100 from TGEP) of 2
m×2 m in size. The characteristics of all seedlings/saplings and
coppices of both indigenous and exotic species were recorded.
Species density, frequency and abundance were calculated by the
methods of Shukla and Chandal (2000). The relative density,
relative frequency and relative abundance were calculated by the
methods of Misra (1968). Importance Value Index (IVI) were
calculated by the methods of Shukla and Chandal (2000). The
collected species were identified (Prain 1903; Brandis 1906;
Heining 1925; Das et al. 2001; Dey 2006). During the present
study, eight diversity and richness indices were analyzed to get a
clear picture of regeneration diversity tree species in the study
areas:
SDI=S/N (1)
where, SDI is the species diversity index (Odum 1971); S the total
number of species; N the total number of individuals of all the
species.
R= (S-1) / Ln (N) (2)
where, R is the species richness index (Margalef 1958); n is the
number of individuals of each species.
H = -∑ PiLnPi (3)
where, H is the Shannon-Winner diversity index (Michael 1990),
and Pi is the number of individuals of one species/Total number
of individuals in the samples.
Hmax=Ln (S) (4)
where, Hmax is Shannon’s maximum diversity index (Kent et al.
1992), S is the total number of species.
EH=H/Hmax (5)
where, EH is Shannon’s equitability index (Kent et al. 1992); H
the Shannon-Winner diversity index; Hmax the Shannon’s maxi-
mum diversity index.
E= H/Log (S) (6)
where is E is the species evenness index (Pielou 1966), H the
Shannon-Winner diversity index, and S the total number of spe-
cies.
D=∑ Pi
2 (7)
where, D is the Simpson index (Magurran 1988), Pi is the Num-
ber of individuals of one species/Total number of individuals in
the samples. As biodiversity increases, the Simpson index de-
creases. Therefore, it is worthy to get a clear picture of species
dominance.
D'=1- D (8)
where, D' is dominance of Simpson index.

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553
Fd (%) = Nf /Ti × 100 (9)
where, Fd is the family relative density (%) (Mori et al. 1983), Nf
is No. of individuals in a family; Ti is the total no. of individuals.
'Fr (%) = Ns/Ts×100 (10)
where, Fr is the family relative diversity (%); Ns is No. of species
in a family; Ts is the total number of species.


Results

Natural regeneration status of species in KNP and TGEP

In the two study sites, about 3818 individuals were found in 800
m2-sampled areas (Table 1). About 55 species under 28 families
with 43 genera were encountered in the two sites, with KNP’s
forest having the highest number of species (43 species), and
TGEP forest (31 species). In case of regeneration mode, almost
95% species were found to regenerate through seedling, sapling,
and rest 5% of the species was through coppicing. Twenty-nine
species occurred in KNP while rests were found in two sites.
About 72% families is represented by only one species, while
7% families is represented by two and three species and 14%
families comprises more than three species in the two study sites.
Families with high numbers of different species are Meliaceae (6
species), Moraceae (6 species), Mimosaceae, Myrtaceae, Com-
bretaceae and Euphorbiaceae every (3 species), Rutaceae, Caes-
alpiniaceae, Verbenaceae both (2 species in each) and rest of the
families comprise one species. Besides, three unidentified spe-
cies also were found in two study sites. Moreover, there were 15
exotic species in the study sites among 9 families (1 unidentified
species with family) where 40 indigenous species under 24 fami-
lies (2 unidentified species with families) recorded. In case of
exotic species, 55.56% family comprises only one species,
33.33% family with two species and 11.11% family with three
species. In case of indigenous species, 79.17% families comprise
only 1 species, 4.17% family with two species, 8.33% family
with more than three species.
Family importance value (FIV) index of recorded species is
also given in Table 1. The individuals number of species and FIV
were the highest for the recorded family of Meliaceae (individu-
als 550, FIV 26.3), followed by Moraceae (individuals 472, FIV
24.24), Combretaceae (individuals 241, FIV 12.3), Euphor-
biaceae (individuals 231, FIV 12), Mimosaceae (individuals 208,
FIV 11.4), Cassuarinaceae (individuals 29, FIV 2.7) and lowest
for Santalaceae (individuals 19, FIV 2.43). Results also revealed
that regeneration frequency of both indigenous and exotic spe-
cies was varied in five different habitats (forest, fallow land,
homestead, roadside, and others) (Table 2). Among these five
habitats, diversity of indigenous species was highest in forest (36
species), followed by roadside (11 species), fallow land (7 spe-
cies), others (5 species) and homestead (4 species) while it was
different for exotic species. Diversity of exotic species was high-
est in roadside (12 species), followed by fallow land (9 species),
forest (7 species), homestead (3 species) and others (2 species).
Results of this study also indicated that total fifty-five species in
forest had the highest number of species (43 species), followed
by roadside (23 species), fallow-land (16 species), others and
homestead (7 species in each). The composition and richness of
understory plant species in different habitats are presumably due
to their different responses to abiotic factors such as differential
light levels, nutrient availability, water availability, wind, and
temperature (Laska 1997; Svenning 2000; Siebert 2002).

Quantitative characters of natural regenerated species

The total seedling/sapling/coppice of exotic and indigenous spe-
cies were estimated 1238 and 2580 respectivey from two study
sites (Table 3, 4). For exotic species, the highest density was
recorded for Tectona grandis L.f. from both natural regeneration
and coppices (0.62), followed by Xylia dolabriformis Benth. (K.
kerrii) (0.45), and Albizia procera (L.) Benth. (0.43). But in case
of indigenous species, the highest density was found for Chick-
rassia tabularis Juss. (0.59), followed by Artocarpus chaplasha
Roxb. (0.58) and Terminalia arjuna Bedd. (0.57), and lowest for
Santalum album L. (0.1).
Exotic species had the highest frequency (34.5%) of T. gran-
dis, followed by X. dolabriformis (28.5%), and A. procera
(26.5%). On the other hand, the highest frequency of indigenous
species was calculated for C. tabularis (32.5%), A. chaplasha
and T. arjuna both contains (32%).
Some major exotic species with highest values of abundance
were for Senna siamea Lam. (1.88), T. grandis (1.78) and Uni-
dentified-1 (1.77). But indigenous species with highest abun-
dance are for Dipterocarpus turbinatus Gaertn. (2.7), Aquilaria
agallocha Lamk. (2.5) Zanthoxylum rhetsa (Roxb.) DC. (2.18),
Bombax ceiba Linn. (2.1) and Hydnocarpus kurzii King (2.08).
The relative density of T. grandis was the highest (11.7%),
followed by X. dolabriformis (8.47%), and A. procera (8.09%)
for exotic species. Furthermore, in indigenous species the rela-
tive density for C. tabularis (4.23%) was the highest, followed
by A. chaplasha (4.16%) while the lowest for S. album (0.69%)
respectively.
The relative frequency of T. grandis in exotic species was the
highest (10.5%), followed by X. dolabriformis (8.69%), Swiet-
enia mahagoni (Linn.) Jacq. (8.23%), A. procera (8.08%) and
lowest for Unidentified-1 (3.35%) respectively. In indigenous
species, the relative frequency of C. tabularis were highest (4%),
followed by A. chaplasha and T. arjuna together (3.93%) in that
order.
However, the relative abundance of S. siamea was the highest
value (7.83%), followed by T. grandis (7.44%), Unidentified- 1
(7.39%) in that order. In case of indigenous species, D. turbina-
tus (3.92%) has highest relative abundance, followed by A. agal-
locha (3.64%) Z. rhetsa (3.16%) and B. ceiba (3.05%) respec-
tively.
T. grandis had the highest IVI value (29.66), followed by X.
dolabriformis (23.67), A. procera (22.86) and Lagerstroemia
speciosa (L.) Pers. (22.66) respectively for exotic species. C.
tabularis has the highest IVI value (10.8) in indigenous species,
followed by A. chaplasha (10.7), T. arjuna (10.6), Michelia
champaca L. (10.1), Syzygium grande (Wt.) Wall. and Apha-

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554
namixis polystachya (Wall.) R. N. Park. (9.85 each).

Table 1. Species composition, species classification, mode of availability of regeneration, family relative density (FRD), family relative diversity
(FRDI), and family importance value (FIV) index of recorded species in KNP and TGEP of Northeastern Bangladesh

Family Scientific name Local name I/E*
Mode of available
regeneration*
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Naturalized
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Coppice
Coppice
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Coppice
Se, Sa
Se, Sa
Se, Sa
Se, Sa
Number of
individuals**
51
64
43
88
49
77
54
29
113
66
62
89
94
73
64
79
75
58
63
89
69
84
106
102
84
117
83
91
73
68
85
55
115
55
43
99
67
93
101
55
44
42
72
87
53
19
39
63
40
63
123
42
39
39
28
FRD (%) FRDI (%) **FIV
1. Anacardiaceae
2. Apocynaceae
3. Bixaceae
4. Bombacaceae
5. Caesalpiniaceae
1. Mangifera indica Linn.
2. Alstonia scholaris R.Br.
3. Bixa orellana Linn.
4. Bombax ceiba Linn.
5. Cassia fistula Linn.
6. Senna siamea Lam.
Aam
Chatim
Lotkon
Shimul
Sonalu
Minjiri
Kanchon
Jhau
Arjun
Horitoki
Bahera
Garjon
Bhubi
Amoloki
Chagalledi
Sissoo
Chalmugra
Nageswar
Menda
Lohakat
Tatul
Jarul
Champa
Pitraj
Neem
Chickrasi
Mahagoni
Kuma
Bokhain
Sirish
Malakanna
Akashmoni
Chapalish
Kanthal
Dewa
Dumur
Bot
Joggodumur
Dhakijam
Eucalyptus
Eucalyptus
Tal
Kadom
Bajna
Bel
Chondon
Bakul
Udol
Agor
Gamar
Teak
Shewra
I
I
I
I
E
E
I
I
I
I
I
I
I
I
I
E
I
E
I
E
I
E
I
I
I
I
E
I
I
E
E
E
I
I
I
I
I
I
I
E
E
I
I
I
I
I
I
I
I
E
E
I
E
I
I
1.37
1.72
1.16
2.37
3.39
1.92
1.92
1.92
1.92
3.85
3.3
3.65
3.08
4.29
7.24
6.Caesalpinoideae 7. Bauhinia acuminata Linn.
7.Cassuarinaceae 8. Casuarina equisetifolia Linn.
9. Terminalia arjuna W & A.
10. Terminalia chebula (Gaerth.)Retz.
11. Terminalia bellirica (Gaertn) Roxb.
9.Dipterocarpaceae 12. Dipterocarpus turbinatus Gaertn.
13. Baccaurea ramiflora Lour.
14. Phyllanthus emblica Linn.
15. Trewia polycarpa Benth.
11. Fabaceae 16. Dalbergia sissoo Roxb.
12. Flocourtiaceae 17. Hydnocarpus kurzii (King) Warb.
13. Guttiferae 18. Mesua nagassarium (Burn. f.) Kost.
14. Lauraceae 19. Litsea monopetala (Roxb.) Pers.
20. Xylia dolabriformis Benth. (K. kerrii) 15. Leguminosae
21. Tamarindus indica Linn.
16. Lythraceae 22. Lagerstroemia speciosa (Linn.) Pers.
17. Magnoliaceae 23. Michelia champaca Linn.
24. Aphanamixis polystachya (Wall.) R. N. Park.
25. Azadirachta indica A. Juss.
26. Chickrassia tabularis Juss.
27. Swietenia mahagoni (Linn.) Jacq.
28. Toona ciliata J.Roem.
29. Melia sempervirens (Linn.) All.
30. Albizia lebbeck (Linn.) Benth.
31. Albizia procera Benth.
32. Acacia auriculiformis Willd.
33. Artocarpus chaplasha Roxb.
34. Artocarpus heterophyllus Lamk.
35. Artocarpus lacucha Buch-Ham.
36. Ficus roxburghii Wall
37. Ficus benghalensis Linn.var.krishnae
38. Ficus racemosa Linn.
39. Syzygium grande (Roxb.) DC.
40. Eucalyptus camaldulensis Dehn.
41. Eucalyptus grandis Hill & ex Maiden.
22. Palmae 42. Borassus flabellifer Linn.
23. Rubiaceae 43. Anthocephalus chinensis (Lamk.)
44. Zanthoxylum rhetsa (Roxb.) DC. 24. Rutaceae
45. Aegle marmelos (Linn.) Correa.
25. Santalaceae 46. Santalum album Linn.
26. Sapotaceae 47. Minosops elengi Linn.
27. Sterculiaceae 48. Sterculia villosa Roxb.
28. Thymeleaceae 49. Aquilaria agallocha Lamk.
50. Gmelina arborea (Roxb.) DC. 29. Verbenaceae
51. Tectona grandis L.f.
30. Urticaceae 52. Streblus asper Lour.
53. Unidentified-1
54. Unidentified-2
55. Unidentified-3
1.45
0.78
6.49
1.92
1.92
5.77
3.38
2.7
12.26 8. Combretaceae
2.4
6.22
1.92
5.77
4.32
11.99 10. Euphorbiaceae
2.13
2.02
1.56
1.7
4.26
1.92
1.92
1.92
1.92
3.85
4.05
3.94
3.48
3.62
8.11
2.26
2.86
14.8
1.92
1.92
11.5
4.18
4.78
26.3 18. Meliaceae
19. Mimosaceae 5.6 5.77 11.37
20. Moraceae 12.7 11.5 24.24
21. Myrtaceae 5.39 5.77 11.16
1.13
1.94
3.77
1.92
1.92
3.85
3.05
3.84
7.62
0.51
1.05
1.7
1.08
5.01
1.92
1.92
1.92
1.92
3.85
2.43
2.97
3.62
3.0
8.86
1.13

1.92

3.05
Unidentified
Notes: *I/E, I is Indigenous and E is Exotics; Se is Seedling and Sa is Sapling; ** Unidentified species are not included.

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Table 2. Status of regeneration of species at different habitats in KNP and TGEP, Bangladesh
Species location
Species
Fallow land
N=16(29.09)
Forest
N=43(78.18)
Homesteada
N=7(12.73)
Roadside
N=23(41.82)
Othersb
N=7(12.73)
Indigenous, n=40 (100) 7 (17.5) 36 (90) 4(10) 11 (27.5) 5 (12.5)
Exotic, n=15 (100) 9 (60) 7 (46.67) 3(20) 12 (80) 2 (13.33)
Notes: Values in the parenthesis indicate the percentage and N (summation of n) indicates the total number of species; aHomestead indicates surrounding forest
dwellers house; bOthers indicates canals, streams and tea gardens, etc.

Table 3. Density (D), Frequency (F), Abundance (A), Relative density (RD) Relative Frequency (RF), Relative Abundance (RA), Importance
value index (IVI) of exotic regenerating species in KNP and TGEP, Bangladesh
Scientific name Density RD (%) Frequency (%) RF (%) Abundance RA (%) IVI
Acacia auriculiformis Willd.
Albizia lebbeck (Linn.) Benth.
Albizia procera Benth.
Cassia fistula Linn.
Senna siamea Lam.
Dalbergia sissoo Roxb.
Eucalyptus camaldulensis Dehn.
Eucalyptus grandis Hill & ex Maiden.
Gmelina arborea (Roxb.) DC.
Lagerstroemia speciosa (Linn.) Pers.
Mesua nagassarium (Burn. f.) Kost
Swietenia mahagoni (Linn.) Jacq.
Tectona grandis L.f.
Xylia dolabriformis Benth. (K. kerrii)
Unidentified- 1
0.28
0.34
0.43
0.25
0.39
0.4
0.28
0.22
0.32
0.42
0.29
0.42
0.62
0.45
0.2
5.23
6.47
8.09
4.66
7.33
7.52
5.23
4.19
5.99
7.99
5.52
7.9
11.7
8.47
3.71
18
20
26.5
17.5
20.5
25
18.5
14.5
22.5
26
18
27
34.5
28.5
11
5.49
6.1
8.08
5.34
6.25
7.62
5.64
4.42
6.86
7.93
5.49
8.23
10.5
8.69
3.35
1.53
1.7
1.6
1.4
1.88
1.58
1.49
1.52
1.4
1.62
1.61
1.54
1.78
1.56
1.77
6.37
7.09
6.69
5.84
7.83
6.59
6.2
6.33
5.84
6.74
6.72
6.41
7.44
6.51
7.39
17.09
19.66
22.86
15.84
21.41
21.73
17.07
14.94
18.69
22.66
17.73
22.54
29.66
23.67
14.46

Table 4. Density (D), Frequency (F), Abundance (A), Relative density (RD), Relative Frequency (RF), Relative Abundance (RA), Importance
value index (IVI) of indigenous regenerating species in KNP and TGEP, Bangladesh
Scientific name Density RD (%) Frequency (%) RF (%) Abundance RA (%) IVI
Aegle marmelos (Linn.) Correa.
Alstonia scholaris R.Br.
Anthocephalus chinensis (Lamk.) Rich ex.Walp.
Aphanamixis polystachya (Wall.) R. N. Park.
Aquilaria agallocha Lamk.
Artocarpus chaplasha Roxb.
Artocarpus heterophyllus Lamk.
Artocarpus lacucha Buch-Ham.
Azadirachta indica A. Juss.
Baccaurea ramiflora Lour.
Bauhinia acuminata Linn.
Bixa orellana Linn.
Bombax ceiba Linn.
Borassus flabellifer Linn.
Casuarina equisetifolia Linn.
Chickrassia tabularis Juss.
Dipterocarpus turbinatus Gaertn.
Ficus benghalensis Linn.var.krishnae (C.DC.)
Corner
Ficus recemosa Linn.
Ficus roxburghii Wall
Hydnocarpus kurzii (King) Warb.
Litsea monopetala (Roxb.) Pers.
Mangifera indica Linn.
0.27
0.32
0.36
0.51
0.2
0.58
0.28
0.22
0.42
0.47
0.27
0.22
0.44
0.21
0.15
0.59
0.45
1.92
2.31
2.6
3.69
1.45
4.16
1.99
1.55
3.04
3.4
1.95
1.55
3.18
1.52
1.05
4.23
3.22
17
23
19
30
8
32
16.5
14
26.5
27
18.5
15.5
21
14.5
7
32.5
16.5
2.09
2.83
2.34
3.69
0.98
3.93
2.03
1.72
3.26
3.32
2.27
1.91
2.58
1.78
0.86
4
2.03
1.56
1.39
1.89
1.7
2.5
1.8
1.67
1.54
1.58
1.74
1.46
1.39
2.1
1.45
2.07
1.8
2.7
2.27
2.02
2.76
2.47
3.64
2.61
2.42
2.23
2.31
2.53
2.12
2.02
3.05
2.11
3.01
2.62
3.92
6.27
7.16
7.69
9.85
6.07
10.7
6.44
5.51
8.6
9.25
6.35
5.48
8.81
5.41
4.92
10.8
9.17
0.34 2.42 24.5 3.01 1.37 1.99 7.42
0.47
0.5
0.38
0.32
0.26
3.36
3.58
2.71
2.28
1.84
26
27
18
15.5
19.5
3.2
3.32
2.21
1.91
2.4
1.79
1.83
2.08
2.03
1.31
2.6
2.67
3.03
2.96
1.9
9.16
9.56
7.95
7.14
6.14

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556
Continued Table 4
Scientific name Density RD (%) Frequency (%) RF (%) Abundance RA (%) IVI

Melia sempervirens (Linn.) All.
Michelia champaca Linn.
Minosops elengi Linn.
Phyllanthus emblica Linn.
Santalum album Linn.
Sterculia villosa Roxb.
Streblus asper Lour.
Syzygium grande (Roxb.) DC.
Tamarindus indica Linn.
Terminalia arjuna W & A.
Terminalia bellirica (Gaertn) Roxb.
Terminalia chebula (Gaerth.)Retz.
Toona ciliata J.Roem.
Trewia polycarpa Benth.
Zanthoxylum rhetsa (Roxb.) DC.
Unidentified- 2
Unidentified- 3

2.4
3.75
1.23
3.63
0.8
2.46
1.84
3.87
2.83
3.93
2.21
2.89
3.2
1.91
2.46
1.66
1.29

1.87
1.74
1.95
1.24
1.46
1.58
1.4
1.6
1.5
1.77
1.72
1.4
1.75
2.06
2.18
1.44
1.33

2.72
2.53
2.84
1.8
2.13
2.29
2.04
2.33
2.18
2.57
2.51
2.04
2.55
3
3.16
2.1
1.94

7.76
10.1
5.48
8.06
3.61
7.03
5.4
9.85
7.5
10.6
6.96
7.32
9.03
7.22
8.77
5.17
4.24
0.37
0.53
0.2
0.37
0.1
0.32
0.21
0.51
0.35
0.57
0.31
0.33
0.46
0.32
0.44
0.2
0.14
2.64
3.83
1.41
2.64
0.69
2.28
1.52
3.65
2.49
4.08
2.24
2.39
3.29
2.31
3.14
1.41
1.01
19.5
30.5
10
29.5
6.5
20
15
31.5
23
32
18
23.5
26
15.5
20
13.5
10.5

Biological diversity indices of regenerating species

According to Khumbongmayun et al. (2005), the species richness
is one of the foremost criteria in recognizing the importance of
an area for conservation of biodiversity. Rahman et al. (2000),
believed that higher the value of diversity, greater would be the
stability of community. Different biological diversity indices for
natural regeneration of indigenous and exotic species in KNP
and TGEP of Bangladesh are explored in Table 5. Diversity indi-
ces such as Species diversity index (SDI), Species richness index
(R), Shannon-Winner diversity index (H), Species evenness in-
dex (E), Simpson index (D) were analyzed to get a clear picture
about the regeneration status of both indigenous and exotic spe-
cies. Shannon-Winner diversity index (H), Shannon’s maximum
diversity index (Hmax), Species richness index (R) and domi-
nance of Simpson index (D') value were found to be highest for
indigenous species where Species evenness index (E) and Simp-
son index (D) value were highest for exotic species. However,
the value of Shannon’s equitability index (EH) and Species diver-
sity index (SDI) was same for both species. The results indicated
that the regeneration status of the two study areas were very
adequate and specify, which is converted into a diversity rich
forest through protection and scientific management of regener-
ating species as well as whole forest ecosystem.

Table 5. Different biological diversity indices for regeneration status
in KNP and TGEP, Bangladesh
Diversity index Species
H Hmax EH SDI R E D D'
Indigenous
Exotic
3.62
2.66
3.69
2.71
0.98
0.98
0.01
0.01
4.92
2.01
2.26
2.27
0.03
0.07
0.97
0.93
Notes: H is Shannon-Winner diversity index, Hmax is Shannon’s maximum
diversity index, EH is Shannon’s equitability index, SDI is Species diversity
index, R is Species richness index, E is Species evenness index, D is Simpson
index, D' is Dominance of Simpson index.

Discussion

Information on the species composition of a forest is essential for
its wise management in terms of economic value, regeneration
potential (Wyatt-Smith 1987) and ultimately may be leading to
conservation of biological diversity (Verma et al. 1999). Natural
regeneration potential is an important indicator for any forest
ecosystems. Nevertheless, very scanty or almost no information
is available on the composition, distribution and status of natural
regeneration species of the study forests. In two biodiversity
conservation areas (Khadimnagar National Park (KNP) and Tila-
gaor Eco-Park (TGEP)), a detailed survey of regeneration spe-
cies of trees was undertaken to provide complete information on
the species composition, distribution and quantitative structure of
species. However, in the present study, the number of species
recorded in KNP and TGEP was much higher than that recorded
in other natural and plantation forests of Bangladesh (Table 6).

Table 6. Summary of regeneration plant inventory in KNP and
TGEP, Bangladesh
Variable Indigenous
Exotic
Number of individuals
Number of species
Number of family
Number of genera
Disturbance scores*
2580
40
20
28
9
1238
15
11
15
6
Notes: *Disturbace score includes- pest and disease attack, human and wild
animals interference, loss of habitat and shelter for animals, drought, poor
drainage, low moisture, associated species, unsustainable collection of fuel
wood and medicinal plants, over-exploitation of species, etc.

Hossain (1994) recorded 52 tree species of 32 families in the
Sitapahar natural forest of Chittagong Hill Tracts (South) forest
division of Bangladesh. Ahmed and Bhuyian (1994) found 42

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Journal of Forestry Research (2011) 22(4): 551−559

557
known and few unknown regenerating species in the natural
forest of Cox’s Bazar Forest Division, Bangladesh. Hossain et al.
(2004) in a comparative study of natural regeneration of natural
forest and enrichment plantation in Chittagong (south) forest
division, Bangladesh recorded 64 species from natural forest and
40 species from enrichment plantations; Alamgir and Al-Amin
(2007) documented 39 species under 18 families in a proposed
biodiversity conservation area (Bamerchara and Danerchara) in
Chittagong, Bangladesh.
The various studies showed that open canopy might be in fa-
vor of seed germination and seedling establishment through in-
creased solar radiation on the forest floor (Khan et al. 1987; Ka-
davul et al. 1999). Regeneration is a critical phase of forest man-
agement, because it maintains the desired species composition
and stocking after disturbances (Duchok et al. 2005). In Bangla-
desh, there are approximately 5000 species of angiosperms (Nath
et al. 1998) and the regeneration density or regeneration capacity
of species is low in a high-competition environment, i.e. in grass
and ferns.
The Importance Value Index (IVI) of any species indicates the
dominance of species in a mixed population (Sharma 1979).
From the present study, it was found that Tectona grandis, Xylia
dolabriformis, Albizia procera, Lagerstroemia speciosa, Swiet-
enia mahagoni, Dalbergia sissoo Roxb., and Cassia siamea
Lam., were dominated in exotic species. In indigenous species,
the dominated species were estimated for Chickrassia tabularis,
Artocarpus chaplasha, Terminalia arjuna, Michelia champaca,
Ficus roxburghii, Baccaurea ramiflora, and Syzygium grande,
so on as well as these species are important from the both biodi-
versity conservation and commercial point of view.
On the family level, Moraceae and Meliaceae were the domi-
nant families for both exotic and indigenous species. Probably,
the dominance of these two families is due to the excellent dis-
persal capacities of their seeds, pollen grains, etc. by wind, water,
birds, mammals, bats, and humans. The natural growing of fruit
tree species like Aegle marmelos, Artocarpus chaplasha, Arto-
carpus heterophyllus, Artocarpus lacucha, Azadirachta indica,
Bixa orellana, Bombax ceiba, Borassus flabellifer, Ficus rox-
burghii, Ficus bengalensis, Ficus racemosa, Mangifera indica,
Terminalia chebula, Terminalia belerica, Phyllanthus emblica,
Tamarindus indica and Syzygium grande etc. species provide
food and natural habitat to the animal diversity.
Forest Department’s plantations strategy was considered as
one of the major causes for forest and biodiversity degradation.
The targeted plantation aimed at producing high valued timber
trees. In addition, exotic trees or mono species were planted in
these areas. Therefore, no biodiversity conservation strategy was
considered. Bamboo, rattan, and agar are also planted in an ex-
tensive area. The plantation practices, including clearing and
subsequent weeding of the proposed plantation areas have con-
tributed to biodiversity loss and habitat loss for the wildlife. Ma-
jor threat for natural regeneration in both sites is indiscriminate
collection of fuelwood by the surrounding people at sapling pe-
riod of tree species leaves. Another severe threat to the newly
regenerated tree species is grazing and trampling by the cattle of
the adjacent people. Therefore, a core area and a buffer zone
would need to be demarcated for forest resource management
and sufficient care is needed to implement various developmen-
tal activities related to forest management.
Public awareness has to be developed and special priority
ought to give to conserve and protect the regeneration of tree
species, which are facing tremendous pressure from increasing
population and urbanization. So, effective forest policies are
needed for sustainable management of forest ecosystem which is
not only to manage and conserve the existing the natural re-
sources, ecosystems but also for the restoration of natural ecosys-
tem through cooperation and support of local dwellers. A project
named Integrated Protected Area Co-management (IPAC) is
running since 2009 in KNP collaborated with the local people
that will be helpful to improvements in forest and resource con-
servation and buffer zone with some specific forest management
objectives. These two biodiversity conservation areas are rich in
regenerating species that could result in the establishment of a
diverse natural forest if the seedlings or saplings of the regenerat-
ing species are conserved according to proper management strat-
egy.


Conclusions

The findings of present study provide a complete view of regen-
eration status in the study areas and possess a rich regeneration
species composition, status and diversity. Data from five types of
habitats proved that they are also profound in their surrounding
locations. The present study suggests that disturbances such as
extraction of seedling/saplings for fuelwood, grazing, distur-
bance of seed dispersal, etc. has brought a decline in plant com-
munities. The present study in and around two-biodiversity con-
servation areas is a small sample for exploring the actual thing
for natural regeneration composition, status and diversity. Fur-
ther study is highly recommended to reexamine the present find-
ings. The study finally concludes that a proper protection from
human interferences and scientific management of natural regen-
eration of the study areas may lead a biodiversity rich site in the
country.

Acknowledgments
We are also thankful to the anonymous reviewers for insightful
comments on earlier versions of the paper. We are especially
grateful to the department of Forestry and Environmental Sci-
ences, SUST for literature support.


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