العدد الثاني

1. Jfuas No.2 December 2013
21
Composition and Structure of Boswellia papyrifera Stands
and their Sustainability in Jebel Marra, Western Sudan
Mohamed A. Khamis¹, Siegfried Uhlig² and Huberts Pohris²
1- Department of Forestry, Faculty of Environmental Sciences & Natural Resources,
University of Al-fashir
2- Institute of International Forestry and Forest Products, Tharandt‫و‬ Faculty of Forest, Geo-
and Hydro Sciences, Dresden University, Germany
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2. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
22
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Abstract
The present study was conducted in Boswellia papyrifera stands in
Jebel Marra area, which is located in the western part of the Sudan.
Boswellia Papyrifera (Del.) Hochst. is a multipurpose tree that grows
on the rocky shallow soils of the hilly elevated areas. It produces gum
resin that has various local uses, pharmaceutical and industrial
applications. In addition to the multiple uses of its wood, the leaves
are used as fodder and it appears to play a great ecological role. The
area covered in this study was 224 hectares. Systematic sampling
technique with camp unit was used. Where two clusters were
established and a total of 84 sample plots were obtained. Diameter and
height of the trees with diameter equal to and greater than seven
centimeter were measured in each plot. Boswellia stand characteristic
parameters such as species richness, species area curve, stem number,
basal area and importance value index (IVI) for the total stand were
analyzed. The results revealed about 28 tree species, 19 genera and 15

3. Jfuas No.2 December 2013
23
families in the sampled area. The analysis of species area curve
showed that the different species are not homogeneously distributed
throughout the stand. Boswellia papyrifera exhibited the highest
values of abundance (114), frequency (80), dominance (31.24), and
importance value index (184.8). Only three young seedlings were
observed for Boswellia papyrifera species in the sampled area, while
Dichrostaschys cinerea showed the highest percentage of natural
regeneration (68.1%) followed by Acacia gerrardii (6.7%), Grewia
villosa (5.3%), Combretum collinum (4.2%), Grewia
flavescens(3.9%), Acacia seyal (3.8%), Albizia amara (2.8%) and
Acacia Senegal (1.5%). The absence of regeneration of Boswellia
papyrifera trees and the domination of regeneration by Dichrostaschys
cinerea, as an invasive species, may jeopardize the future
sustainability of this stand. Also the domination of Acacias indicates
the direction of successional change of these stands towards the
Acacia wood land savannah, which requires the adoption of other
management strategies.
Key words: Boswellia Papyrifera; composition and Structure;
sustainability; important value index; Jebel Marra.
Introduction
Sudan is characterized by a diversity of natural woody perennials
which produce wood and non-wood forest products. However, gums
and gum resins are among the products that contribute significantly in
the livelihood of the local inhabitants and in the economy of the

4. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
24
country as a whole. Boswellia Papyrifera (Del.) Hochst. is one of the
important tree species, which is found in most states of the Sudan,
south of latitude 14° N (El Amin 1990, Vogt 1995, Wickens 1976
Khamis 2001 Adam 2004 and Khamis 2008). It is a multipurpose tree
that produces gum resin. In addition to the multiple uses of its wood in
local carpentry work and other wood related industries (match-boxes,
pencils, air-conditioning particles, etc.) the leaves are used as fodder
for livestock during the dry season. Despite its apparent ecological
and economic roles in rural areas of the Sudan, Boswellia papyrifera
stands lack adequate planning and proper management and utilization,
as is the case in other African countries. In Sudan, there are number of
factors, which jeopardize the development of the Boswellia papyrifera
stands such as fires, agricultural encroachment, uncontrolled grazing,
insects and diseases, which also affect the natural regeneration
(Ogbazghi, 2006, Eshete et al, 2012) .
Jebel Marra Forests (JMFs) is located in Western Darfur State in
Sudan. It was established in the 1950s as a division of the Forests
National Corporation (FNC), formerly known as Department of
Forests (DF), with the responsibilities of managing and conserving the
forest resources in the area. The most interesting feature of Jebel
Marra is its Island-like position amidst the lowlands of the Sahelo-
Sudanian transition zone, in the very heart of the African continent, in
the low rainfall Savannah zone (Wickens 1976). It receives average
annual rainfall that ranges between 500-900 mm, with a recorded
maximum of 1066 mm and minimum of 294 mm. The forests and

5. Jfuas No.2 December 2013
25
woodland savannah in Jebel Marra area cover an area of
approximately 196000 hectares (Khamis 2001). It constitutes a very
important element of the Sudan’s natural heritage and biological
diversity - hosting about 400 species of plants. Boswellia Papyrifera
(Del.) Hochst. is one of the important tree species, which occupies the
western sub-hills of Jebel Marra and covers an area of
approximately17500 ha. Reliable information about the stand
composition and structure and growing stock is lacking. Therefore no
management plans have been constructed for proper and sustainable
management of these stands. Also the present utilization practices
have led to severe deterioration of the Boswellia papyrifera stands.
This situation has been aggravated by improper tapping practices by
inexperienced people, which may lead to more deterioration of these
stands. Accordingly the aim of this study was to carry out an
inventory to assess the structure and composition of these stands and
their future sustainability. However, this study mainly emphasized on
the management of the Boswellia papyrifera stands with the objective
of providing reliable information about stand composition and
structure that form bases for adequate planning and proper
management of these stands.
Materials and methods
Jebel Marra is located between latitudes 12 º 30′ and 13º 30′ N and
longitudes 24º and 24º 30′ E, in the low rainfall Savannah zone in the
western part of the Sudan. It covers an area of about 196000 hectares

6. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
26
(ha). The average temperature range is 20-30º C. The rainfall in the
area ranges between 500-900 mm per annum fluctuating from year to
another. The soils in Jebel Marra are classified into three categories as
follows; first is the basement complex, Aeolian sands and the volcanic
mountain complex soils. The geology of the area is characterized by
the formation of the basement complex, which is over lied by the
volcanic massif. The area is covered by many small isolated or groups
of hills, which form the Jebel Marra Mountains (Andrew 1948).
The study area is relatively rich in vegetation cover with
considerably high diversity. It is characterized by montane vegetation
zone which consists of three groups of vegetation, namely; hill
savannah, upland steppe and meadow and gallery forests (Wickens,
1976). Boswellia papyrifera stands fall in hill savanna vegetation
group with Boswellia papyrifera trees dominating the hill catena,
either as pure stand or in association with other species such as
Sclerocarya birrea, Sterculia setigera, Acacia gerardii, Anogeissus
leiocarpus, Lanea fruticosa, Commiphora africana, Stereospermum
kunthianum, Terminalia brownii, Combretum golutinosum and Albizia
amara. The shrubby species include Dichrostachys cinerea,
Combretum molle, Combretum collinum, Grewia flavescense, G.
villosa, and Adenium obesum. The ground vegetation includes;
Eragrostis cilianensis, Pennnisetum pedicellatum, Acanthospermum
hispidum and Cenchrus biflorus.
Reconnaissance survey was carried out first covering the study area.
Observations concerning Boswellia papyrifera stands were made,

7. Jfuas No.2 December 2013
27
which include general stand condition, regeneration and the visible
factors affecting the stand. This was followed by management
inventory where systematic cluster sampling with camp unit was used
and two clusters were established. The area covered in this study was
224 ha and 84 sample plots were established. The sample plots are
circular in shape and with two radii; the first is 17.84 m (area = 0.1 ha)
where all trees with diameter at breast height (DBH) equal to and
greater than seven cm were measured. The second radius is five
meters (area = 0.008 ha) in which the number and heights of stems of
the regeneration were measured.
The measured variables in each sample plot included number of
trees, diameter at breast height (dbh), total height (th) for (trees with
dbh ≥7 cm) and the number of regeneration (dbh 7 cm).Then species
richness, species area curve (it is ƚŚĞ ŚŽŵŽŐĞŶĞŝƚLJ Žƌ ŚĞƚĞƌŽŐĞŶĞŝƚLJ
ŽĨ ƚŚĞ ĚŝƐƚƌŝďƵƚŝŽŶ ŽĨ ƚŚĞ ĚŝĨĨĞƌĞŶƚ ƐƉĞĐŝĞƐ ƚŚƌŽƵŐŚŽƵƚ Ă ĐĞƌƚĂŝŶ
ƐƚĂŶĚ͕ obtained by counting the number of species in each five sample
plots (0.5 ha)), stem number (Abundance (AB)), number of
individuals per species (Absolute abundance (AAB)), percentage of
each species of the total stem number per hectare (Relative abundance
(RAB)), occurrence or absence of a given species in a sample plot
(Frequency (FR)), percentage of occurrence of a certain species
(Absolute frequency (AFR)), percentage of the total of absolute
frequencies ;Relative frequency (RFR)), basal area ;Dominance
(BA)), the sum of the individual stem basal areas (Absolute
dominance (ABA)), the percentage of a given species of the total stem

8. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
28
basal area measured (Relative dominance (RBA)) and importance
value index (IVI) (sum of the relative abundance + relative frequency
+ relative dominance) for the total stand, as a measure of ecological
significance of a species in a certain forest type were analyzed,
according to Curtis and McIntosh, (1951) and Kershaw, (1978).
Results
The results of analysis of Boswellia papyrifera stands presented in this
study include; species richness, species area curve, stem number, basal
area and importance value index (IVI) for the whole stand. There
were 28 species in total (six species as regeneration), comprising 19
Genera and 15 Families, in the sampled area including the
regeneration (Figure 3). The highest number of species were found in
the first five sample plots which was seven species, followed by four
new species in the second five sample plots, then the number
decreased towards the end of the last five sample plots. Zero indicates
no further new species was found in five sample plots (0.5 ha), as
shown in (Table 1) and (Figure 1), dŚŝƐ ƐŚŽǁƐ ƚŚĂƚ ƚŚĞ ĚŝĨĨĞƌĞŶƚ
ƐƉĞĐŝĞƐ ĂƌĞ ŶŽƚ ŚŽŵŽŐĞŶĞŽƵƐůLJ ĚŝƐƚƌŝďƵƚĞĚ ƚŚƌŽƵŐŚŽƵƚ ƚŚĞ ƐƚĂŶĚ͘
Results of this analysis also included the abundance, absolute
abundance, relative abundance, frequency, importance value index,
the stem number and the basal area per hectare for all species in the
Boswellia papyrifera stands, for the trees with dbh ≥7 cm, as
presented in (Table 2). For Boswellia papyrifera, it shows the absolute
abundance of 956, abundance of 114, relative abundance of 75 %

9. Jfuas No.2 December 2013
29
(percentage of species) and it was found in 80 sample plots
(frequency), absolute frequency 95, relative frequency 30.9,
dominance of 31.24, relative dominance of 78.9 and importance value
index (IVI) of 184.8, which was the highest importance value index
(IVI) found in the sampled area. The co-dominant species are
Anogeissus leiocarpus, Acacia gerardii, Albizia amara, Sclerocarya
birrea, Sterculia setigera and Albizia amara with IVI of 30.9, 14.0,
11.9, 11.06, 10.77, 7.06 and 6.84 respectively. The rest of the species
showed IVI of less than 5, as shown in (Table 2 and Figure 2).
Results have also shown that the average number of trees per
hectare (abundance) for all species with dbh ≥ 7cm is about 152
trees/ha, of which Boswellia papyrifera constitutes 114 trees/ha about
75% (relative abundance). The average basal area per hectare for all
species was estimated to be about 39.6 m² per hectare (Table 2).
Concerning the natural regeneration, only 3 seedlings of Boswellia
papyrifera were observed in the sampled area. The regeneration was
dominated by the Acacias and shrubby species, namely
Dichrostaschys cinerea which showed the highest percentage of
natural regeneration (68.1%) followed by Acacia gerrardii (6.7%),
Grewia villosa (5.3%), Combretum collinum (4.2%), Grewia
flavescens (3.9%), Acacia seyal (3.8%), Albizia amara (2.8) and
Acacia senegal (1.5%). While the rest of the listed species exhibit less
than 1% regeneration. For Boswellia papyrifera species there was
almost total absence of regeneration (0.4%) (Figure 3).

10. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
30
Table 1: No. of new species discovered in each 5 plots for trees with dbh ≥ 7
cm in the sampled area of Boswellia papyrifera stand, Jebel Marra,
Sudan
Area (ha) Number of species Area (ha) Number of species
o.5 7 5 2
1 4 5.5 1
1.5 1 6 0
2 3 6.5 0
2.5 1 7 1
3 0 7.5 1
3.5 1 8 0
4 0 8.5 0
4.5 0 Total 22
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ϲ
ϲ͘ϱ
ϳ
ϳ͘ϱ
ϴ
ϴ͘ϱ
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ϭ
Ϯ
ϯ
ϰ
ϱ
ϲ
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ϴ
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ϭ Ϯ ϯ ϰ ϱ ϲ ϳ ϴ ϵ ϭϬ ϭϭ ϭϮ ϭϯ ϭϰ ϭϱ ϭϲ ϭϳ
ƌĞĂ ;ŚĂͿ
EƵŵďĞƌ ŽĨ ƐƉĞĐŝĞƐ
Figure 1: Species-area curve for Boswellia papyrifera stand, trees with DBH
≥ 7 cm in the sampled area, Jebel Marra, Sudan

11. Jfuas No.2 December 2013
31
Table 2: composition and structure, for trees with DBH ≥ 7 cm in the B.
papyrifera stand, Jebel Marra, Sudan.
Species A B C D E F G H I
Acacia gerrardii 43 5.1 3.30 23 27.4 8.92 0.73 1.8 14.0
Acacia nilotica 3 0.4 0.26 1 1.2 0.39 0.05 0.1 0.75
Acacia senegal 2 0.1 0.07 2 2.4 0.78 0.22 0.6 1.45
Acacia seyal 19 2.3 1.51 14 16.7 5.44 0.02 0.1 7.05
Albizia amara 29 3.5 2.30 20 23.8 7.75 0.77 1.9 11.9
Anogeissus leiocarpus 107 12.7 8.36 41 48.8 16 2.60 6.6 30.9
Azanza garkeana 1 0.1 0.07 1 1.2 0.39 0.01 0.03 0.49
Balanites aegyptiaca 5 0.6 0.40 5 6 1.95 0.21 0.5 2.85
Boscia salicifolia 2 0.1 0.07 2 2.4 0.78 0.06 0.2 1.05
Boswellia papylifera 956 114 75.00 80 95 30.9 31.24 78.9 184.8
Comb. glutinosum 13 1.5 0.99 6 7 2.28 0.21 0.5 3.77
Comb. molle 1 0.7 0.46 1 1.2 0.39 0.01 0.03 0.88
Commiphora africana 12 1.4 0.92 8 9.5 3.09 0.21 0.54 4.55
Dalbergia melanoxylon 6 0.1 0.07 5 6 1.95 0.08 0.2 2.22
Ficus glumosa 1 0.01 0.07 1 1.2 0.39 0.08 0.2 0.66
Lanea barteri 3 0.4 0.26 3 3.6 1.17 0.13 0.13 1.56
Lanea fruticosa 19 2.3 1.51 11 13 4.23 0.2 1.1 6.84
Sclerocarya birrea 26 3.1 2.03 15 17.9 5.83 1.26 3.2 11.06
Sterculea setigera 22 2.5 1.64 15 17.9 5.83 1.3 3.3 10.77
Terminalia brownii 1 0.1 0.07 1 1.2 0.39 0.03 0.07 0.53
Terminalia laxiflora 1 0.1 0.07 1 1.2 0.39 0.03 0.07 0.53
Ziziphus abyssinica 2 0.2 0.13 2 2.4 0.78 0.02 0.05 0.96
Total 127 152 307 39.62
Absolute abundance (A), Abundance (B), Relative abundance (C), Frequency (D),
Absolute frequency (E), Relative frequency (F), Dominance (G), Relative dominance (H)
and Importance value index (I)

12. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
32
Tree species
Figure2: Importance Value Index (IVI) for trees with DBH ≥ 7 cm in the
Boswellia papyrifera stand, Jebel Marra, Sudan.

13. Jfuas No.2 December 2013
33
Tree species
Figure3: Regeneration in Boswellia papyrifera stands, Jebel Marra, Sudan
Discussion
The species composition in the Boswellia papyrifera stands is
relatively rich compared to the rocky shallow poor soils of the hill
slopes. They were also comparatively rich in comparison to 37 species
in more or less similar stands in South Kordofan, as presented by
Khamis (2008).
It is obvious from the results above that the dominant species is
Boswellia papyrifera with 184.8 IVI, but it shows very low or total
absence of regeneration. While the domination of regeneration by
Dichrostaschys cinerea and Acacia gerardii (Acacias) indicates a
gradual change of this stand from Boswellia papyrifera stand to

14. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
34
Acacia and shrubby woodland in the future. Dichrostaschys cinerea
which is of low value, is considered to be an invasive species and
strong competitor in this stand and may jeopardize the growth and
future development of the valuable species.
Also as shown by the results, there were about 152 trees per hectare in
average for trees with dbh ≥ 7, which is higher compared to 60 trees
per hectare stated in (Khamis, 2008) in South Kordofan with more or
less similar environmental conditions, especially the Boswellia stands.
Boswellia papyrifera constitutes about 75% of the total number of
trees in the sampled area which is very high and indicates its
domination at the present time but the absence of its regeneration may
jeopardize its future sustainability, if no managerial intervention is
taken to reverse the situation.
The findings of this study also show that, there were about 98
seedlings per hectare as regeneration of different species. This amount
of regeneration is comparatively sufficient to sustain the stand in
mixed forest. But the domination of regeneration by the Acacias
indicates the direction of successional change of these stands towards
the Acacia woodland savannah. In conclusion, the stand of Boswellia
papyrifera is endangered by the absence of regeneration of this
species and invasion by non-economic ones.
However, the execution of prescribed silvicultural measures which
should include enrichment planting of Boswellia papyrifera trees,
after releasing the stands from the competing undesirable species, like
Dichrostachys cinerea and promoting an integrated management of

15. Jfuas No.2 December 2013
35
the valuable ones like Boswellia papyrifera for resin, Acacias for gum,
and Combretaceae sps. for wood, within the stands of Boswellia
papyrifera are highly recommended. Effective measures should be
worked out against forest fire, grazing and browsing, cutting and
chopping of trees and the other negative impacts. Also, the
requirement for encouragement, motivation and increasing the
awareness of the direct users of these forests who cause damage to
Boswellia papyrifera stands, through extension and training programs
to participate in planning, protection and sustainable management of
these stands.
References
1. Adam, A. A. 2004. Aspects of Ecology and Management of Boswellia
papyrifera in Jebel Marra mountain area, Ph D thesis, University of
Khartoum, Sudan.
2. Andrew, F. W. 1948: The vegetation of the Sudan. In Agriculture in
the Sudan, pages 32-61.
3. Curtis, J. and Mcintosh, R. P. 1951. Interrelation of certain analytic
and synthetic phytosociological characters. Ecology, 31, 434-445 pp..
(In: KERSHAW, K. A. 1978: Quantitative and Dynamic plant
ecology 2nd edition. ELBS and Edward Arnold (Publisher) Ltd).
4. El Amin, H. M. 1990. Trees and Shrubs of The Sudan, Ithaca Press,
Biddles Ltd, Guildford and Kims Lynn, England.

16. ‫اﻟﻔﺎﴍ‬ ‫ﺟﺎﻣﻌﺔ‬–‫ﻣﺠﻠﺔ‬‫اﻟﻌﻠﻮم‬‫اﻟﺘﻄﺒﻴﻘﻴﺔ‬-‫اﻟﻌﺪد‬‫اﻟﺜﺎين‬–‫دﻳﺴﻤﱪ‬2013‫م‬
36
5. Eshete, A., Teketay, D., Lemenih, M. and Bongers, F. 2012.
Effects of resin tapping and tree size on the purity, germination and
storage behavior of Boswellia papyrifera (Del.) Hochst. seeds from
Metema District, northwestern Ethiopia. Journal of Forest Ecology
and Management 269 (2012) 31–36
6. Kershaw, K. A. 1978. Quantitative and Dynamic plant ecology, 2nd
edition. ELBS and Edward Arnold (Publisher) Ltd).
7. Khamis, M. A. 2001. Management of Boswellia papyrifera stands for
Resin Production in Jebel Marra Area, Present Situation and Future
Prospects, M.Sc. Thesis, Dresden, Germany.
8. Khamis, M. A. 2008. Assessing the Potentials of Boswellia
papyrifera stands for Sustainable Management in Southern Kordofan
State, PhD Thesis, Juba University, Khartoum, Sudan.
9. Ogbazghi, W. 2006. The Distribution and Regeneration of Boswellia
papyrifera In Eritrea, British Ecological Society, Journal of Applied
Ecology, 43, 1188–1195
10. Vogt, K. 1995. A field worker’s guide to the identification,
propagation and use of common trees and shrubs of the Sudan; (SOS)
Sahel international London, UK.
11. Wickens, G. E. 1976. The flora of Jebel Marra (Sudan Republic) and
its geographical affinities.-Kew Bull. Add. Ser.5.-London