White Meranti


INTRODUCTION

The Standard Malaysian Name for the timber of the Anthoshorea group of Shorea (Dipterocarpaceae). Vernacular names applied include meranti (Peninsular Malaysia and Sarawak) with various epithets, melapi (Sabah) with various epithets and other localised names too numerous to list here. Major species include S. agami, S. assamica, S. bracteolata, S. dealbata, S. henryana, S. hypochra, S. lamellata, S. resinosa and S. roxburghii. The sapwood is white and is moderately sharply differentiated from the heartwood, which is almost white when fresh and becomes light yellow-brown on exposure.

Also known as White Meranti (Brunei); Lum-bao (Cambodia); Makai (India); Dammar putih, Dammar tenang putih, Kayu tahan and Meranti putih (Indonesia); Mai khae hom, Mai kheen fai and Mai kheen khan yon (Laos); Kyilan (Myanmar); Manggasinoro and Yellow lauan (Philippines); Dumala dun (Sri Lanka); Chan, Khiam Ka Nom, Khiem Kha Norng, Kiam Ka Nom, Phayom, Saya-khao, Sukrom and Takhian-Sai (Thailand).


DENSITY

The timber is a Light Hardwood with a density of 495-995 kg/m3 air dry.


NATURAL DURABILITY

The white meranti is classified as moderately durable under Malaysian conditions. Untreated timbers of white meranti of standard test dimensions of 50 mm x 50 mm x 600 mm were subjected to graveyard tests at the Forest Research Institute Malaysia (FRIM). The average service life for the four species of white meranti tested are respectively 2.6 years (S. bracteolata), 3.6 years (S. hypochra), 4.5 years (S. roxburghii) and 4.1 years (S. henryana). The sapwood of white meranti appears to be rather readily and rapidly attacked by 'pin-hole' borers after felling. The timber is not resistant to marine borer attacks even though it has high content of silica in the cells. Creosote/diesel fuel treated sleepers of white meranti (S. bracteolata) have been reported to last as long as 19 years at a colliery in Peninsular Malaysia (Thomas, 1949).


PRESERVATIVE TREATMENT

The timber is amenable to preservative treatment.


TEXTURE

Texture is moderately coarse and even, with rarely straight, usually shallowly interlocked or occasionally deeply interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group C (Engku, 1988b) or SG 5 (MS 544:Part 2:2001).


Strength Properties of White Meranti

Species

Test Condition

Modulus of Elasticity(MPa)

Modulus of Rupture(MPa)

Compression parallel to grain
(MPa)

Compression perpendicular to grain
(MPa)

Shear strength(MPa)

S. bracteolata

Green

12,700

63

33.8

2.6

6.1

Air dry

-

-

44.3

3.9

9.4

S.
henryana

Green

18,400

109

61.8

9.4

14.0

Air dry

19,400

132

67.1

11.0

14.2

S.
hypochra

Green

14,400

79

42.1

4.9

9.0

Air dry

15,700

97

51.7

5.9

10.0

S. roxburghii

Green

10,800

73

40.4

5.2

9.0

Air dry

11,500

90

47.7

7.0

10.6


MACHINING PROPERTIES

It is easy to slightly difficult to resaw in the green condition and slightly difficult to very difficult in the air dry condition. Cross-cutting is also easier in the green than in the air dry condition. Planing is easy to slightly difficult and the surface produced is smooth to rough.


Machining Properties of White Meranti

Species

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

S. bracteolata

Green

slightly difficult

easy

moderately easy

rough

easy

rough

-

-

Air dry

difficult

slightly difficult

moderately easy

rough

easy

rough

moderately easy

rough

S.
henryana

Green

slightly difficult

slightly difficult

easy

rough

easy

smooth

-

-

Air dry

very difficult

very difficult

slightly difficult

rough

difficult

moderately smooth

-

-

S.
hypochra

Green

easy

easy

easy

smooth

easy

rough

-

-

Air dry

slightly difficult

slightly difficult

slightly difficult

moderately smooth

moderately easy

rough

moderately difficult

rough

S. roxburghii

Green

easy

fairly easy

easy

smooth

easy

smooth

-

-

Air dry

slightly difficult

slightly difficult

slightly difficult

moderately smooth

easy

rough

moderately difficult

rough


NAILING PROPERTY

Nailing property ranges from good to poor depending on the species.


AIR DRYING

The seasoning characteristics of some species of white meranti are summarised below:

Species

Time to air dry (months)

Remarks

13 mm thick boards

25 mm thick boards

38 mm thick boards

S. assamica

-

3.5

-

Fairly slow drying.

S. bracteolata

2

-

3

Fairly fast drying; slight cupping, bowing, end-checking and surface-checking, insect and fungi attacks.

S. henryana

3

-

5

Fairly slow drying; only slight end-checks and staining.

S. hypochra

3

-

5

Fairly slow drying; only slight splitting and staining.

S. roxburghii

3

4

5

Fairly slow drying; no defects.


KILN-DRYING

Kiln Schedule J is recommended. The timber dries rapidly without any defects. 25 mm thick boards take approximately 5 days to kiln-dry from 50 to 10% moisture content. When drying timbers of thickness above 40 mm and up to 75 mm, the relative humidity of the original drying schedule should be 5% higher in each case and for timber of thickness greater than 75 mm, the relative humidity should be increased correspondingly by 10%.

Kiln Schedule J

Moisture Content (%)

Temperature (Dry Bulb)

Temperature (Wet Bulb)

Relative Humidity (%) (approx.)

F

C

F

C

Green

135

57.0

123

50.5

70

50

135

57.0

119

48.0

60

40

140

60.0

118

47.5

50

30

150

65.5

121

49.0

40

20

170

76.5

127

53.0

30


SHRINKAGE

The shrinkage of some species of white meranti is summarised below: 

Species

Shrinkage (%)
(Green to air dry)

Remarks

Radial

Tangential

S. assamica

1.1

2.9

Shrinkage rather high.

S. bracteolata

1.8

3.0

Shrinkage fairly high.

S. henryana

1.1

2.6

Shrinkage rather high.

S. hypochra

1.3

2.7

Shrinkage rather high.

S. roxburghii

0.6

1.7

Shrinkage fairly low.


DEFECTS

White meranti generally contains less defects compared with other forms of merantis. The incidence of borer attacks in heartwood of the timber is quite negligible. The sapwood is rather readily and rapidly attacked by 'pin-hole' borers. Similar to most white coloured timbers, white meranti is also liable to blue stain infection (particularly the sapwood portion) if the timber is inadequately ventilated. Old trees of this timber may contain brittle-heart or in more serious cases, hollow-heart. Compression failures or cross-breaks are commonly associated with the brittle or hollow heart. Logs appear to split very little after felling.


USES

The timber is suitable for light to medium construction, posts, beams, joists, rafters, door and window frames and sills, planking, staircase (carriages, newel, risers, sprandrel framing, stringer, railing, tread, bullnose, round ends and winders), panelling, mouldings, partitioning, furniture, flooring, decking, railway sleepers, tool handles (non impact), disposable chopsticks, vehicle bodies (framework, floor boards and planking), ship and boat building (keels, keelsons, framework and general planking) and plywood.


REFERENCES

  1. Choo, K. T. & Lim, S. C 1986. Malaysian Timbers - White Meranti. Timber Trade leaflet No. 102. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 12 pp.
  2. Engku Abdul Rahman Chik. 1998b. Basic and Grade Stresses for Strength Groups of Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 38. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 13 pp.
  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 Institute Malaysia, Kuala Lumpur. 48 pp.
  4. MS 544:Part 2:2001. Code of Practice for the Structural Use of Timber: Permissible Stress Design of Solid Timber.
  5. Tam, M. K. 1986. Unpublished report.
  6. Thomas, A. V. 1949. The Service Life of Sleepers in Malayan Railways. Mal. For. Vol:XII; 114.
  7. Wong, T. M. 1982. A Dictionary of Malaysian Timbers. Revised by Lim, S. C. & Chung, R. C. K. Malayan Forest Records No. 30. Forest Research Institute Malaysia, Kuala Lumpur. 201 pp.