Simpoh


INTRODUCTION

The Standard Malaysian Name for the timber of Dillenia spp. (Dilleniaceae). Vernacular names applied include simpoh (Peninsular Malaysia, Sabah and Sarawak) with various epithet. Major species include D. borneensis, D. excelsa, D. grandifolia, D. pulchella and D. reticulata. The sapwood is lighter in colour and merges gradually into the heartwood, which is red-brown, sometimes with a purplish tinge and darkens on exposure.

Also known as Poplea and San (Cambodia); Kukulava and Kulava (Fiji); Dillenia (India); Kendikara and Simpur jangkang (Indonesia); Phao and San kham (Laos); Mai-masan, Thabyu and Zinbyum (Myanmar); Dillenia and Majongga (Papua New Guinea); Katmon and Katmon-layugan (Philippines); Kapuchu and Mudi (Soloman Islands); Godapura (Sri Lanka); and Masan, San, San-Na and Tamasi (Thailand).


DENSITY

The timber is a Medium Hardwood with a density of 675-820 kg/m3 air dry.


NATURAL DURABILITY

Graveyard test on 38 sticks of simpoh (D. grandifolia) with dimension of 50 mm x 50 mm x 600 mm were carried out to determine the natural durability of the timber. All the test sticks were destroyed within the first year of test. Simpoh is therefore, classified as not durable (Jackson, 1965). The timber is also reported to be susceptible to powder-post beetle attacks (Desch, 1957).


PRESERVATIVE TREATMENT

Its amenability to preservative treatment is classified as average.


TEXTURE

Texture is coarse and uneven, with straight to shallowly interlocked grain.


STRENGTH PROPERTIES

The timber falls into Strength Group C (Engku, 1988b) or SG4 (MS 544:Part 2:2001). 


Strength Properties of Simpoh (D. grandifolia)

Test Condition

Modulus of Elasticity (MPa)

Modulus of Rupture (MPa)

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

Shear Strength (MPa)

Green

14,300

76

39

5

8


MACHINING PROPERTIES

It is fairly easy to resaw and cross-cut. Planing is easy to fairly easy and the planed surface produced is smooth.


Machining Properties of Simpoh (D. grandifolia)

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

fairly easy

fairly easy

easy

smooth

easy

slightly rough

-

-

Air dry

moderately easy

moderately easy

fairly easy

smooth

easy

slightly rough

easy

smooth


NAILING PROPERTY

The nailing property is rated as poor.


AIR DRYING

The timber dries moderately slowly, with cupping and splitting as the major defects. 13 mm thick boards take approximately 4 months to air dry, while 38 mm thick boards take 5 months.


KILN-DRYING

Kiln Schedule C is recommended. 25 mm thick boards take about 14 days to dry. Simpoh has been found to be very prone to surface-checking during drying and thus, due care should be taken to prevent any form of harsh treatment.


Kiln Schedule C

 Moisture Content (%)

Temperature (Dry Bulb)

Temperature (Wet Bulb)

Relative Humidity (%) (approx.)

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 high, with radial shrinkage averaging 2.2% and tangential shrinkage averaging 3.9%.


DEFECTS

Freshly felled logs are usually sound except for some heart shakes. The logs are liable to split badly soon after felling, frequently throughout the whole length of the logs. Sawn material of simpoh is prone to spring badly. Other degrades of the timber such as warping and twisting are common during seasoning. Some specimens of simpoh were found to be attacked by powder-post beetles.


USES

The timber has an attractive silver figure and is suitable for decorative works, plywood, interior finishing, panelling, mouldings, joinery, cabinet making, flooring, furniture and ornamental items. It is also suitable for posts, beams, joists, door and window frames and sills, railway sleepers, staircase (tread, stringer, apron lining, carriage, newel and riser), vehicle bodies (planking), ship and boat building (general planking), piling, columns (light duty), cooling tower (non-structural members) as well as telegraphic and power transmission posts and cross arms.


REFERENCES

  1. Desch, H.E. 1957. Manual of Malayan Timbers. Vol. 1 Malay. For. Rec. No.15.
  2. Engku Abdul Rahman Chik. 1988b. Basic And Grade Stresses For Some Malaysian Timbers. Malayan Forest Service Trade Leaflet No. 38. The Malaysian Timber Industry Board And Forest Research Institute Malaysia, Kuala Lumpur. 13 pp.
  3. Jackson, W. F. 1965. The Durability Of Malayan Timbers. Malayan Forest Service Trade Leaflet no.28.
  4. Lim, S. C. 1982. Malaysian Timbers - Simpoh. Malaysian Forest Service Trade Leaflet No. 67. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 8 pp.
  5. 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.
  6. MS 544: Part 2: 2001: Code Of Practice For Structural Use Of Timber. Permissible Stress Design of Solid Timber.
  7. 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.