Khulna University Studies

KhulnaUniversityStudies3⁽2):537

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⁵⁴⁰

LIFESCIENCES

KhulnaUniversityStudies3(2): 537

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⁵⁴⁰

ASTUDY ON PHYSICAL PROPERTIES OF TWO^BAMBSOOSPECIES BORAK⁽Bambusa BalcooaROXB

.

^)AND

JAWA

⁽Bambusa SalarkhaniiALAM⁾

OF

BANGLADESH

M .

^O

.

Hannan^*

,

M

.

^N

.

^{Islam andM}

. N .

^Islam

Forestry andWood Technology Discipline

.

Khulna University,Khulna

-

^{9208,Bangladesh}

.

KUS

-

^01/09

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⁰²⁰⁵⁰¹

Manuscript received: May 2^,2001;Accepted:September 4^,2001

Abstract:Bamboo, a renewable naturalresourcein villagesandforestsof Bangladesh,is widely used in almost all purposes by the poorpeople.Shrinkage,greendensity, ovendrydensity^andmoisturecontentoftwo bamboospecies of Bangladesh-Borak⁽Bambusa balcooaRoxb)andJawa⁽Bambusa salarkhaniiAlam⁾werestudiedatdifferentheights⁽top

.

^{middle andbutt).}Shrinkage of both wall

-

thicknessand diameterwerecarried outand was found noticeable^atovendrycondition.Althoughpercentageofshrinkage decreased withthe increaseofheight,and therewas no significant differencebetween them.Maturebamboo had lower wallthickness shrinkage comparedtothatof immature bamboos.Againjawa had smaller shrinkage^valuesin bothwall

-

thickness and diameter compared^to thoseof borak.Densityvariation wasfoundamongall the parameters butnone^ofthemwassignificant.Moisture contentwasfoundto varybetween andwithin species.The differencewasfound tobe statistically significant in case of species and^maturity.

Key words:Shrinkage;Bambusabalcooa:Bambusa salarkhanii:Borak;Jawa;Bamboo

Introduction

Bambooisa perennial grass made up of woody stemsorculms

.

They

occur

mostlyin natural vegetation of tropical^, sub

-

tropical and temperate regions and they are abundant in tropical Asia (Purushotham 1963,

TewariandSingh 1979^,Tewari1981, George 1985⁾

.

Some bamboos have been recorded from the latitudeas far north

as 46

° and

as

far south as 47° and ^occurring at elevation

as

high

as 4000 m

⁽Soderstrom and Calderon 1979⁾

.

Thedistribution^{ofbamboo is}richin the

areas

between the Tropicof Cancer and^theTropic ofCapricorn^,especiallyforthe clumpformingbamboos(Uchimura 1987⁾

.

Bamboois the most versatile material usedforrural housingin Bangladesh

. It

isgenerally regarded as “poor man’stimber”

.

Itisusedin bothround and split formsⁱⁿrural construction work. Thickwalled bamboos are usedfor houseposts and rafters; andthin walled bamboos for walls^andframes

.

Over 70 million people of Bangladeshlive inhousesmadeofbamboo⁽Latifet al1987)

.

Unlike wood, bamboo starts shrinking during the initial ^stages of drying and has ^shown considerable shrinkage inwall thickness^,as wellas,in^diameterof theculm(Rehman andIshaq 1947^,Kishanetal1956⁾

.

Most of the defects that

appear

in bamboo during seasoning are caused due to excessive or unequal shrinkage

.

^So it is necessary^toknow the extentoftheshrinkagewiththe variationofdensity and moisture content of bamboo before

placing

it into actual

use .

But two most important bamboo species of ^Khulna region namely borak(BambusabalcooaRoxb

.

^)andjawa(Bambusa salarkhaniiAlam)have

no -

^{suchtype of}

literature. Thisstudy

was

carried outwith these two major bamboo speciesofwhich ^pnewas thick

-

^walled,

named borak ⁽Bambusa balcooa Roxb.) and theother was thin

-

^{walled, named jawa (}Bambusa salarkhanii Alam⁾

.

Materials and Methods

Investigations

were

carried out with borak andjawa as thesetwospeciesare relativelyimportant due totheir utilization in the Khulna region

.

Six mature and immature culms of each species were collected from Batiaghata, Khulna. Six culms

were

collected as a precaution of splitting^samples for diameter shrinkage while drying

in

the

oven .

The maturityofthebamboos

was

determinedarbitrarilyfrom their positions inthe clump

.

^Bamboosstanding inside^theclump were^{taken to}be matured^whilethose growingoutside theclump were consideredtobeimmature

.

Colorand condition of the branches^werealsoconsidered fordetermining the maturityofthebamboos

.

Thespecimens for^shrinkagestudy

was

collected from three different heights

-

^{butt,middleand topofthe}

culm

.

^Aftercutting the top portion^, samples

were

collected from bottom^, middle and topof the culm

.

^The

specimens for wall ^thickness shrinkage were in the form of 2.5

cm

long rings while thespecimens for diameter

-

^shrinkage

were 5

cm long ring of the culm of ^variouslengths. In thisway a total ofsix rings of

’Correspondingauthor:Tel:+88

-

⁽⁰⁴¹

> -

721971, 720171

-

^3;Ext

.

^{278;Fax: 88041}

-

^{731244;email:<forest@khulna.bangla.neO}

537

DOI: https://doi.org/10.53808/KU S.2001.3.2.0109-L

Hannanelal

.

,2001^;Astudyon physical properties of two^bambsoospecies borak⁽Bambusabalcooa roxb.⁾and jawa(Bambusa salarkhaniialam)ofbangladesh

which three were 2.5cmlong and the restwere5 cmlong fromeachofthe two bamboospeciesand thusa total of 36 rings of 2.5 cm^and36 rings of 5cmlong were^obtainedfromeachofthe species

.

W

,

^Wj

/ \ \ \

^W

,

w

.

D

=

^{(D|+D2)/ 2}

W

=

^{(W1+W2+W3+W4)/ 4}

(b

,

Fig

.

¹

.

^Theposition of^datacollection from a sample^,(a)Measurement^forwall

-

^thickness

-

^{shrinkage (b)}

measurementfordiametershrinkage⁽Talukder and^Sattar1980)

.

The wall thickness was measured at four perpendicularly positions to each other while the diameter shrinkage was measured along two diameters perpendicular to each other ⁽Fig. 1.). Wall thickness and diametermeasurementswere made^withaslide callipers to thenearest0.002cm

.

Therefore the samples were placedin an ^electric

oven

maintained^at60° Cand then temperaturewas gradually ^{raised to}103°C ± 2 in order toavoiddryingdefects

.

The sampleswereweighed at regularintervals after 24^hoursuntiltheweights became constant

.

^The measurements in ^wall thickness^anddiameter were ^{then taken}

.

Asmall numberof samples both diameter shrinkage and wall thickness shrinkage study wasfound^splitted whiledrying in the oven

.

Samplesfor moisture content anddensity determination were^taken intheform ofaspecimenof 5cmlong ringfrom top,middle^{and butt}

.

Density wasdetermined on ^{the basis}ofbothgreen and ovendrybasis.For determination of green volume^{the sample}was weighted just after^felling.Thedriedsamplewassoakedin meltedparaffin^{and the}ovendry^volumewasdetermined.The weight measurementswere^{taken inanelectric} balance toan accuracy of 0.001 gm.In boththecases^thevolumewasascertainedby the waterdisplacement method

.

Results andDiscussion

Shrinkageofwall thickness anddiameterwasexpressedaspercentageof green dimensions

.

Thedensity was articulatedasgm/c³.Theaveragevalueof wall

-

^thickness

-

shrinkage and diameter

-

shrinkage were 6.95^,17.86 forborak hence 7.85,11.23 for jawa respectively.Theaveragedensityof green^andovendry condition was 0.65^,0.52^and 0.76^{, 0.71gm/c3for borak and jawa}respectively

.

The average green moisture content was 102.44% for^borakand 84.34%^forjawa.

Shrinkageof wall

-

thickness percentage isshown in^Fig

.

^2.Shrinkage of wall

-

thickness^of jawaatdifferent heightof both mature^andimmature bamboo were not significant^atboth5%and 1%level of significance

.

For borak^, shrinkage of wall

-

thickness within mature and immaturebamboosatdifferent height positions wasnot significantly different

.

Although significant variations were observed^betweenspeciesat5^{% level}of significance

.

30

2^g DJawa ^Borak 20

15 10 5

0

tOr r r rOr

2

s

^,

I 1

1 s

I

Top

1 s

S

Middle

rtrtghtposttora

I , 1 I

Bun

Jawa

E

^»

\

!

^ra

!

V

1

-

&⁶

F

a4i

f ,

n*1

—

¹

—

Borak

S

i

Top

£

^fi_{«3 «3}

2

I I

Middle HdtftPCTiSam

§ a

s 1

E

e

Butt

Fig.2

.

^{The wall}

-

^thickness

-

^{shrinkageof bamboos Fig.3}

.

The diameter

-

^{shrinkageofbamboos at}

atdifferent maturity and different heightpositions differentmaturity anddifferent^heightpositions

538

Khulna University Studies3(2⁾:537

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⁵⁴⁰

Shrinkage of diameterpercentage is shown in Fig

.

3

. Mature

jawa at top showed the lowest diameter shrinkage and immature borak at buttshowed the highest diameter shrinkage

.

Diameter shrinkage hadshowed the same trend of

wall -

thickness shrinkage

.

Talukdar and Sattar ⁽1980) reported that height factor

was

not to be significant

on

wall

-

thickness shrinkage^forbariala(Bambusa^vulgaris)and mitinga(Bambusa tulda⁾

.

Density values⁽Fig

.

⁴⁾ wereperceptibly different between the values of mature and immature bamboos.Such differences were alsoobserved between thespecies

.

But thisdifference

was

not statisticallysignificant

.

Like shrinkage^,nostatisticalvariation

was

foundin

case

ofdensitywiththe change of height.

JawaGreen BorakGreen 50.8

JawaOvendry Borak Ovendry o u.o

10.7

80.6_0.5

lo

_0.3

8

0.2

o

^.i

0 _.

I i

:

Middle,

|

Butt Height positions

Fig

.

4

.

Thedensity of bamboos^atdifferent maturityanddifferent heightpositions

.

Jawa Borak

C1201

I

^®i

| i l :

₁

8 ⁴⁰

# ²⁰

0

si a

a

g | ^{3 3}

I 1 1 I e 1 1

Top Middle Butt

Height positions

Fig

.

5

.

Themoisturecontent percentage ofbamboos atdifferent maturity and different height positions

.

The moisture contentwasfound to vary betweenand within species(Fig

.

⁵⁾

.

Itvaried withheight andmaturity. The difference was found to be statistically significant in

case

of species and maturity at

5

% level of significance but not for different heights

.

^But none of the differences was however found to be statistically significant for bariala⁽Bambusavulgaris)andmitinga(Bambusatulda⁾⁽TalukdarandSattar 1980⁾

.

Table1

.

Variance analysis

on

variousproperties of^bamboo Shrinkage

Factors Wall

-

thickness Diameter Density Moisture content

Height NS NS NS NS

Maturity NS NS ^{NS *}

Species * * NS *

NS

-

Not Significant^,*Significantat5%level Conclusion

Density^,shrinkagepercentageand moisture content are themost importantphysical^properties fortheend

- uses

and thestudied bamboosarealso the most important species in the Khulna region. Fromthe study it

was

clear that shrinkage^,density and moisture content of borak⁽Bambusa balcooaRoxb

.

)and jawa⁽Bambusasalarkhanii Alam) were not significantly affected by ^{the height} of the culm whereas maturity of bamboo significantly affected only the moisture content

.

^{Shrinkage of both} wall thickness and ^diameter and moisture content of bamboodiffered significantly^withspecies but^densitydidn’ tdiffer significantly

.

References

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.

^,1985

.

Preservative of bamboo

.

In: W

. P .

K

.

Findly⁽ed

.

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Hannan^elat.,2001^;Astudyonphysical properties oftwo bambsoospecies borak(Bambusa batcooaroxb.⁾and jawa(Bambusa salarkhanii alam)of bangladesh

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.

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.

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