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BASIC CHARACTERISTICS OF RUBBER WOOD FOR SOME RECOMMENDED CLONES IN

INDONESIA

H. I. Boerhendy, D. Shinta AgustinaH. Suryaningtyas

SEMBAWA RESEARCH CENTRE

INDONESIAN RUBBER RESEARCH INSTITUTE

INTRODUCTION

Natural rubber plays important roles in Indonesia : export earning for the country, income for > 10 million smallholders, and more than 1.7 million labors working on the rubber industry

Rubber wood was initially used only for fire wood, but with improvement in wood preservation technology the economic value of rubber wood has increased

In many countries (Indonesia,

Malaysia, Sri Lanka, India) rubber

wood has been utilized for a variety of

products such as hard board, particle

board, furniture, fiber board, etc

Breeding program has been directed to

produce not only high latex yielding

clone but also high timber volume

This study was done with the objective

to determine the difference in basic

characteristics of rubber wood (in

relation to suitability for a variety of

products) among several clones

MATERIALS AND METHODS

Research was conducted at the

Experimental Field of Sembawa

Research Centre, Indonesian

Rubber Research Institute

Rubber clones : IRR 39, IRR 44,

GT 1, AVROS 2037, PR 255, PR

261, and seedling (28 years old)

Wood Sampling

Trees felling wood sample preparation

Wood preservation : painting each end of wood cut by

using TB 192 to prevent water evaporation

Analysis : physical, mechanical, chemical

characteristics

Physical and Mechanical

Characteristics

Wood cut (log) of 150 cm representing base, middle

and tip of tree

Testing method : ASTM D 143-94

Physical : bulk density, depreciation from wet to dry

(air and oven dried) - radial and tangential directions

Mechanical : strength (static bending, compression,

shearing, impact bending, cleavage, tension), and

hardness

Chemical Component of Wood

Wood chips of 5 cm thickness were allowed to air dry

milled to sawdust 40 mesh filter and accommodated

by 60 mesh filters

Chemical analysis : lignin and ash contents, solubility

in cold and hot water, holocellulose content (ASTM

1104-56), pentose (ASTM) by using gravimetric method

Fiber Dimension

Wood chips sizing match sticks

The samples were dipped into the organic solution (FPL Madison) for one night at 60oC temperature

After having been apart, fiber was filtered and colored using safranin

Measurement of fiber dimension : fiber length and diameter, lumen diameter, and fiber wall thickness

RESULTS AND DISCUSSION

Clones

Bulk Density Based on

Wt/Vol

(wet)

Wt oven dried/

Wet vol

Wt. oven dry/

vol. air dried

Wt./Vol.

(air dried)

Wt./Vol.

(oven dried)

IRR 39 1.00 0.60 0.61 0.66 0.64

IRR 44 0.94 0.56 0.59 0.66 0.60

GT 1 0.93 0.60 0.64 0.70 0.65

AV 2037 0.92 0.52 0.54 0.60 0.54

PR 255 0.90 0.55 0.60 0.66 0.60

PR 261 0.94 0.56 0.59 0.66 0.59

Seedling 0.93 0.57 0.59 0.66 0.60

Average 0.93 0.57 0.59 0.65 0.61

TABLE 1. AVERAGE OF BULK DENSITY

Clones

Depreciation (%)

Wet – Air dry Wet – Oven dry

R T T/R R T T/R

IRR 39 2.00 3.14 1.57 3.11 5.02 1.61

IRR 44 2.16 2.70 1.25 3.72 4.42 1.18

GT 1 2.62 3.39 1.29 4.04 5.17 1.27

AV 2037 1.62 2.39 1.47 3.15 4.08 1.29

PR 255 1.33 3.36 2.52 2.70 5.44 2.01

PR 261 1.30 3.29 2.53 2.72 5.23 1.92

Seedling 1.37 3.11 2.27 2.65 5.31 2.00

Average 1.77 3.05 1.84 3.16 4.95 1.61

Ramin *) 2.60 5.80 2.23 4.40 9.60 2.18

TABLE 2. AVERAGE DEPRECIATION OF RUBBER WOOD

Physical Characteristics

The bulk density varied from 0.60 to 0.70, could be to

genetic variation, agro-climatic growing condition

Bulk density of rubber wood (relates to strength) is

equivalent to Acasia and Ramin woods (in the category

of medium level) – higher bulk density, stronger

property

T/R rubber wood depreciation - stability of wood

dimension. High T/R (PR 255 and PR 261) require

careful drying process to avoid instability form likes

broken, curved, twisted

0

200

400

600

800

1000

1200

1400

1600

IRR 39 IRR 44 GT 1 AV 2037 PR 255 PR 261 Seedling Average

Clones

Rati

o o

f S

tren

gth

to

Bu

lk D

en

sit

y

MOR (kg/cm2)

Press (kg/cm2)

Radial Shearing (kg/cm2)

Tangential Shearing (kg/cm2)

MOR/BD

FIGURE 1. RATIO OF STRENGTH/BULK DENSITY OF WOOD

HIGHEST LOWEST

Mechanical Characteristics

Overall, all clone showed good strength properties. But

the ratio of strength/bulk density varied (811.63 –

1,368.29), the highest (IRR 39) and the lowest (PR 261)

Higher ratio (strength/bulk density) suitable for

construction material, and the lower ones suitable for

light constructions likes furniture, door frame,

handicraft

Chemical

Compone

nt (%)

Rubber Clones

IRR

39

IRR

44

GT 1 AV

2037

PR

255

PR

261

Seedli

ng

Averag

e

Holoselulo

se

66.89 67.40 67.44 67.65 67.89 67.27 67.10 67.38

Lignin 21.05 20.72 20.99 20.90 20.87 20.50 20.46 20.78

Pentose 17.80 17.30 17.90 17.60 17.90 17.30 17.00 17.54

Solubility

in cold

water

4.75 5.06 4.14 4.77 4.91 5.01 4.61 4.75

Solubility

in hot

water

8.46 8.93 7.86 6.65 8.58 9.01 7.98 8.21

Solubility

in 1%

NaOH

14.35 17.60 14.45 11.55 16.20 12.80 15.90 14.69

Solubility

in 1: 2

benzene

4.46 4.76 4.25 4.62 4.71 4.71 4.57 4.58

TABLE 3. CHEMICAL CONTENTS OF RUBBER WOOD

Chemical Components

All clones revealed similar chemical properties

Wood with high holocelluloses (mixed of cellulose and

hemicelluloses) content – suitable for pulp

Those with high lignin content is less desired – it

produces pulp with a low compression strength

properties and dark color pulp

Fiber dimension

(micron)

Clones

IRR

39

IRR

44GT 1

AV

2037

PR

255

PR

261

Seedlin

g

Averag

e

Length of fiber (L) 1,995

.00

1,657

.00

1,731

.00

1,575

.00

1,579

.00

1,571.

00

1,660.0

0

1,681.2

4

Diameter of fiber

(D)

23.68 27.17 25.02 23.14 23.58 23.25 22.30 24.16

Diameter of lumen

(I)

15.31 15.32 15.66 15.41 15.79 16.38 16.80 15.81

Thickness of cell

wall (W)

4.20 4.42 4.68 3.86 3.95 3.53 3.61 4.13

Runkel number

(2W/1)

0.55 0.58 0.60 0.50 0.50 0.43 0.43 0.61

Weaving strength

(L/D)

84.35 60.99 69.18 68.08 66.96 67.57 74.44 70.32

Ratio of Flexibility

(1/D)

0.646 0.637 0.68 0.67 0.67 0.70 0.75 0.67

Coeffi of Stiffness

(W/D)

0.18 0.16 0.18 0.16 0.16 0.15 0.16 0.16

Class of fiber II II II II II II II II

TABLE 4. FIBER DIMENSION AND ITS

DERIVATIVES

Note : *) stated in percent based on oven dry weight**)quality of fiber was stated as necessity of wood as pulp raw material

Fiber Dimension

Fiber dimension – relates to the strength of the paper

produced

Based on all the fiber dimension properties – rubber

wood is classified into second class in term of fiber

quality (produces pulp sheet with medium level of tear

and tension strengths)

CONCLUSSIONS

Based on physical and mechanical characteristics, rubber

wood was in the second class of strong wood, and no

differences among rubber clones

It could be used as construction materials, wooden

frames, door frame, furniture, and handicrafts, but it

requires proper preservation

Chemical component and fiber dimension of rubber wood

was classified into the second class of fiber quality, which

could be used for MDF