Pauh Kijang


INTRODUCTION

The Standard Malaysian Name for the timber of Irvingia malayana (Simaroubaceae). The ASEAN Standard Name for the timber, which is of Thai origin, is KABOK. Vernacular name for the tree, pauh kijang, is uniformly applied throughtout the country. Only one species, viz. I. Malayana, is recorded in this region. The sapwood is lighter in colour and is only moderately sharply defined from the heartwood, which is yellow-brown with a slight green tinge. A dark grey-brown striped core is found in some logs.

Also known as Cay and Chambak (Cambodia); Bongin and Pauh Kijang (Indonesia); Bok (Laos); and Kabok (Thailand).


DENSITY

The timber is very hard and very heavy with a density of 930-1,250 kg/m3 air dry. The timber is classified under Medium Hardwood in Malaysia.


NATURAL DURABILITY

Jackson (1965) recorded that a consignment of 40 test sticks were all destroyed within 6 years and gave an average life span of 3.1 years. The timber is thus classified as moderately durable. It is not durable in contact with the ground because it is readily attacked by termites but is slightly more resistant to fungi.


PRESERVATIVE TREATMENT

It is difficult to treat with preservatives.


TEXTURE

Texture is moderately fine and even, with shallowly interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group A (Burgess, 1958) or SG3 (MS 544: Part 2:2001).


Strength Properties of Pauh Kijang (I. malayana)

Test Condition

Modulus of Elasticity (MPa)

Modulus of Rupture (MPa)

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

Shear strength (MPa)

Green

-

-

59.0

5.45

13.2

Air dry

-

-

70.5

12.65

17.0


MACHINING PROPERTIES

It is slightly difficult to work when green and is difficult when dry. Planing is difficult but the planed surface is moderately smooth with some grain pick-up in the radial face.


Machining Properties of Pauh Kijang (I. malayana)

Test Condition

Sawing

Planing

Boring

Turning

Re-sawing

Cross cutting

Ease of planing

Quality of finish

Ease of boring

Quality of Finish

Ease of turning

Quality of finish

 Green

 slightly difficult

slightly difficult

 difficult

tangential smooth, radial rough due to picking up of grain

 easy

 rough

 -

-

Air dry

difficult

difficult

difficult

moderately smooth

-

-

-

-


NAILING PROPERTY

The nailing property is rated as poor.


AIR DRYING

The timber seasons slowly with moderate end-checking, surface-checking, insect and fungal attacks as the main sources of degrade. Slight bowing and cupping are also recorded. 13 mm thick boards take approximately 5 months to air dry, while 38 mm thick boards take 7 months.


KILN-DRYING

Kiln Schedule C is recommended.


Kiln Schedule C

Moisture Content (%)

Temperature (Dry Bulb)

Temperature (Wet Bulb)

Relative Humidity (%)

F

C

F

C

Green

105

40.5

101

38.0

85

60

105

40.5

99

37.0

80

40

110

43.5

102

39.0

75

35

110

43.5

100

38.0

70

30

115

46.0

103

39.5

65

25

125

51.5

109

43.0

60

20

140

60.0

118

47.5

50

15

150

65.5

121

49.0

40


SHRINKAGE

Shrinkage is rather high, with radial shrinkage averaging 2.7% and tangential shrinkage averaging 4.3%.


DEFECTS

Pauh kijang is free from defects although mature logs are liable to be hollow. The living tree is subject to borer attacks. 


USES

The timber is not often exploited due to the high buttresses and poor form. It is also very hard and difficult to work. The timber is, however, suitable for heavy construction if treated, piles, railway sleepers, heavy duty furniture, fender supports, flooring (heavy traffic), door and window frames and sills, posts, beams, joists, rafters, telegraphic and power transmission posts and cross arms, tool handles (impact), staircase (carriage, newel, riser, stringer, tread, bullnose, round end and winder) and vehicle bodies (framework and floor boards). The dark streaky core is suitable for decorative works, panelling, mouldings, joinery and cabinet making.


REFERENCES

  1. Burgess, H. J. 1958. Strength Grouping of Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 25. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 15 pp.
  2. Jackson, W. F. 1965. The Durability of Malayan Timbers. Mal. For. Ser. Trade Leaflet No. 28.  
  3. Menon, P. K. B. 1986. Uses of Some Malaysian Timbers. Revised by Lim, S. C. Timber Trade Leaflet No. 31. The Malaysian Timber Industry Board and Forest Research Insitute Malaysia, Kuala Lumpur. 48 pp.
  4. MS 544: Part 2: 2001: Code Of Practice For Structural Use Of Timber. Permissible Stress Design of Solid Timber.
  5. Wong, T. M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S. C. & Chung, R. C. K. Malayan Forest Record No. 30. Forest Research Institute Malaysia Kuala Lumpur. 201 pp.
  6. Zaitun Said. 1985. Malaysian Timbers - Pauh Kijang. Malaysian Forest Service Trade Leaflet No. 99. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 4 pp.