Sena

INTRODUCTION

The Standard Malaysian Name for the timber of Pterocarpus indicus (Leguminosae). Vernacular names applied include angsana (Peninsular Malaysia and Sabah). Only one species is recorded for this country, viz. P. indicus. The sapwood is white or pale straw-coloured and is sharply differentiated from the heartwood, which is golden brown, occasionally streaked with darker stripes.

Also known as Narra (Brunei); Thimbi thimbi (Fiji); Andaman padauk, Bijasal, Padauk and Red sanders (India); Angsana, Linggoa, Oele, Sandana, Sonokembang and Tjempaga (Indonesia); Chan deng and Mai dou (Laos); Ansanah, Padauk and Sena (Myanmar); New Guinea rosewood (Papua New Guinea); Apalit, Narra and Vitali (Philippines); Gammalu (Sri Lanka); Pradoo, Pradu, Pradu-ban and Sano (Thailand); and Vermillion wood (United States of America).


DENSITY

The timber is moderately hard and moderately heavy with a density of 560-690 kg/m3 air dry.


NATURAL DURABILITY

Sena is moderately durable. Its sapwood is readily attacked by fungi and insects.


PRESERVATIVE TREATMENT

Sena is very easy to treat with preservatives.


TEXTURE

Texture is moderately coarse and uneven, due to the ring-porous structure. Grain is interlocked and sometimes wavy.


STRENGTH PROPERTIES

The timber falls into Strength Group C (Burgess, 1958). 


Strength Properties of Sena

Test Condition

Compression parallel to grain (MPa)

Compression perpendicular to grain (MPa)

 Side hardness(N)

Shear parallel to grain (MPa)

Green

31.2

6.14

4,540

9.0


MACHINING PROPERTIES

It is slightly difficult to resaw and cross-cut due to the presence of severely interlocked grain. Planing is easy but the finish is only moderately smooth with some grain pick-up in radial sawn material.


Machining Properties of Sena

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

easy

easy

tangential: smooth; radial: rough due to grain pick-up

moderately easy

smooth

-

-

Air dry

slightly difficult

slightly difficult

easy

moderately smooth

slightly difficult

smooth

moderately easy

smooth


AIR DRYING

The timber seasons fairly slowly, with very little degrade, except for some insect and fungal attacks on the sapwood. 13 mm thick boards take approximately 4 months to air dry and 38 mm thick boards take 5 months.


SHRINKAGE

Shrinkage is low, with radial shrinkage averaging 0.9% and tangential shrinkage averaging 1%.


DEFECTS

The logs are generally free from natural defects.


USES

The timber is one of the rare ring-porous timbers found in this country and as such is highly prized as a cabinet wood. The timber is suitable for all forms of decorative works, joinery, interior finishing, panelling, mouldings, high class furniture, plywood, flooring, staircase (apron lining, baluster, handrail, newel and sprandrel framing) and ornamental items.


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. 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.
  3. Sim, H. C. 1988. Malaysian Timbers - Sena. Timber Trade Leaflet No. 108. The Malaysian Timber Industry Board and Forest Research Institute Malaysia, Kuala Lumpur. 5 pp.
  4. Tham, M. K. 1985. Unpublished report.
  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.