TREE SPECIES COMPOSITION AND ABOVE-GROUND BIOMASS OF SALENDA BRIDGE MANGROVE PATCH

A CASE STUDY OF SALENDA BRIDGE, ILALA, DAR-ES-SALAAM REGION

By Mrumba E. John

2014

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1.1 Background Information of mangrove forests

Mangroves are defined as an association of halophytic trees, shrubs andother plants growing in brackish to saline tidal waters of tropical andsubtropical coastlines (Mitsch and Gosselink 2007). Globally, there are atleast 68 mangrove-obligate species, In Tanzania it is believed that, thereare not less than 8 mangrove species which includes Avicennia marina,Bruguiera gymnorrhiza, Ceriops tagal, Heritiera littoralis, Lumnitzeraracemosa, Rhizophora mucronata, Sonneratia alba, Xylocarpus granatum,Xylocarpus molluccensis

The term Species composition refers to the contribution of each plantspecies to the vegetation. Botanical composition is another term todescribe species composition (Rangelands west, 2013).

Biomass is the total quantity or weight of organism in a given area orvolume (Dictionary.com, 2013).

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Problem statement and Justification

Despite that mangrove forests have major key role in providing fuel energy source for domestic and industrial

uses, building materials, traditional medicines as well as ecosystem sustainability and environmental conservation

particularly on soil conservation and atmospheric carbon sequestrations reduction in coastal regions.

Yet in Tanzania, tree species composition and above ground biomass for mangrove forests in some coastal areas

especially in Salenda bridge mangrove patch have not been well documented. This study was intended on

assessing species composition and above-ground biomass estimation consecutively to assess useful information

principally on carbon stock status of the mangrove forest for the most part of Salenda Bridge mangrove patch.

The findings of this study provides useful and considerable information on sustainable management and

conservation of the patch to the mangrove forests stake holders such forest institutions, Governments and

community as well as baseline information for ongoing projects particularly on environmental conservation such

as REDD+, which will be significant and enormous support of their implementations

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1.3 Objectives

1.3.1 General objective

To assess mangrove tree species composition and above-ground biomassestimation of Salenda Bridge mangrove patch

1.3.2 Specific objectives

To identify mangrove tree species composition of Salenda bridge mangrove patch

To determine mangrove tree species percentage composition of Salenda Bridgemangrove patch

To estimate mangrove tree species above-ground biomass and carbon stock ofSalenda bridge mangrove patch

Research question

1. What are the mangrove tree species compositions of the Salenda bridge mangrove

patch?

2. What are the percentage compositions of each mangrove tree species of Salenda

bridge patch?

3. What will be mangrove tree species above-ground biomass and carbon stock

quantity estimation of Salenda bridge patch?

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3.3 Methods

3.3.1 Sampling techniques

Stratified sampling was employed; since the area of the patch has been alienated by

Msimbazi River, therefore in order to include all individual tree species in measurement

the area was stratified into two strata; the left and right hand sides of the river, equal

sample size were taken where by a random sampling was engaged to allocate the first

plot in each stratified area respectively followed by systematic sampling plots.

Circular plot, 5 m diameter was employed, 12 plots were established. Along the

transect line, each plot was separated by distance of 6.5 m from one plot to another.

19.63 m 2 (1.963 × 10 -3 ha) and 235.62 m 2 (2.356 × 10 -2 ha) Sampling unit and total

sample size was covered each respectively. 117.81 m 2 (1.1781 × 10 -2 ha) was covered

in each strata

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Methods....................cont

Plot interval distance, Sample plot size, number of plots and total samplesize were calculated as follows:-

Plot interval distance (D) = √(Area of the forest / Number of sample plot)

Sample plot size: Circular Area of a plot = πR2; where R = radius of a circular plot

Total sample size = Sample plot size × Number of sample plot

Number of plot: n = TA × Si

PS × 100%

Where: TA = Total forest area; Si = sampling intensity, 50%; PS = plot size (πR2)

Both height and diameter were measured by using Blumeleiss and Calliper eachrespectively, specifically for above-ground Biomass and carbon stock estimationinformation elsewhere tape measure was used to measure distance. Data entryand Recording, A shit form titled “ecological survey summary” was used to capturedata in the field. Microsoft excel was used to analyse data.

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Methods....................cont

Above-ground Biomass and Carbon stock estimation: the following calculations

were required to compute both biomass and carbon stock:-

Basal area(g) calculation: g = πd2/40,000; where d = diameter at breast height, π =

3.14

Volume (V) calculation: V = ffgh; where ff = form factor, h = height

Biomass calculation: Biomass = Wood density × Volume; where wood density =

0.61g/cm3 for Avicinnia marina (Bibliotheca Alexandria-EOL Ar, 2013)

Carbon stock of an individual species: CABG = Biomass × 0.5 ( Bhishma P.S, 2010);

where CABG = Above-ground carbon stock per individual specie, 0.5 = conversion

factor

Carbon stock per single plot: CPLOT =∑ CABG; where ∑ CABG = summation of CABG

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4.0 RESULTS

4.1 Tree species identification

Giesen et al. (2007) reported that, there are at least 68 mangrove-obligate

species globally still it is not possible to find all the mangrove species in

one area. This proves as to why there are only about 10 mangrove species

in America (Mitch and Gosselink 2007). In Tanzania it is believed that there

are not less than 8 mangrove species.

Results showed that, only a single species of mangrove (Avicinnia marina)

found growing and colonizing the study area. The findings from this study

confirm that, it is not possible to get all the mangrove species in one area.

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RESULTS......................cont

Botanical description of Avicinnia marina

Specie name : Avicennia marina Family : Avicinniaceae Habitat: Coastal zone areas

Found on the high levels of swamps

Description:

It willow-like in general appearance and has a light yellowish green foliage

Vertically pointed pneumatophores arise from abundance from long,spreading, horizontal roots

The bark is smooth and greenish yellow when young and variegated greenand reddish in the older trees

USES:

The trunks are used for making small dug-out canoes, and the tree isgenerally used for building carts, for chow and canoe fittings and masts,for furniture such as bedsteads and chairs, and for fitting such as handles.

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RESULTS......................cont

Plate 2:Leaves morphology of Avicinnia marina

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RESULTS......................cont

4.2 Tree species percentage determination

In this study, the findings showed that, 100% of the entire mangrove forest patch was

Avicinnia marina.

4.3 Tree species above-ground biomass and carbon stock

In this study, the findings confer the information that; the total biomass and carbon

stock of Salenda bridge mangrove patch were 22.9tonnes and 11.8tonnes respectively.

According to this study, the findings revealed that, tree species above ground biomass

and carbon stock, per sample area as well as per hectare were 11t, 5.32t, 458.3t/ha and

221.67t/ha.

(Alongi, 2009) reported that, above ground biomass are generally between 150 and

350t/ha in well developed tropical mangroves

The results reflect that, Salenda Bridge area has well developed mangrove forests

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5.0 CONCLUSION AND RECOMMENDATION

5.1 Conclusion:

The study findings discovered that, it is impossible to find all the 68

mangrove species in one area. Only a single species of mangrove

(Avicinnia marina) found growing and colonizing the study area

The schoolwork showed that, the acknowledged tree species composed

and characterises the entire mangrove patch at Salenda Bridge vicinity;

100% was merely Avicinnia marina

Above ground biomass and carbon stock for Avicinnia marina mangrove

tree species were estimated to be 458.3t/ha and 221.67t/ha respectively,

which reflect the well developed mangrove forests at Salenda Bridge area.

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CONCLUSION AND RECOMMENDATION.................cont

5.2 Recommendations:

5.2.1 Forests protection and restoration

In order to enhance the level of biomass and subsequent carbon storage of mangrove forests at

Salenda bridge mangrove patch, efforts to protect the forests will be worthwhile for all stakeholders

including the Government and international institutions, NGO’s and local community.

The protection and restoration of the forests is significant for climate mitigation strategies and will

confer considerable economic benefits to Salenda bridge mangrove patch.

5.2.2 Researcher’s Support, Good Coordination and working Environment

Government, institutions, company, projects, program and other organizations should ensure

support, good coordination and working environment with research institutions and scholars

(researchers).

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CONCLUSION AND RECOMMENDATION.................cont

5.2.3 Mangrove Ecosystem dynamic change and Distribution

Further study should be done on tree species diversity by

other scholars, additional emphasizes should be focused on

studying mangrove ecosystem dynamic change and tree

species distribution in terms of spatial arrangement.

<<<= END....>>> =THANKS.......!

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