Meranti

INTRODUCTION

The Standard Malaysian Name for the dark red and lightweight timber of the genusShorea (Dipterocarpaceae). Vernacular names used include meranti (Peninsular Malaysia and Sarawak) with various epithets, seraya (Sabah) with various epithets,nemesu (Peninsular Malaysia), nemusu (Peninsular Malaysia), seraya (Peninsular Malaysia and Sabah), obar suluk (Sabah) and also various local names too numerous to list here. Major species producing this timber include S. acuminata (partly), S. argentifolia, S. curtisii, S. ovata, S. monticola, S. pauciflora, S. platyclados and S. slootenii. The sapwood is pink with a grey tinge and is not clearly defined from the heartwood, which is medium red to deep red to deep red-brown.  

DENSITY

The timber is a Light Hardwood with a density of 415-885 kg/m³ air dry.

NATURAL DURABILITY

The standard graveyard tests on untreated specimens carried out by the Forest Research Institute Malaysia (FRIM) have classified dark red meranti as moderately durable with an average service life ranging from about 2.0 years (S. singkawang) to 3.9 years (S. platyclados). For the species S. curtisii, S. pauciflora, S. platycladosand S. acuminata, the heartwood is classified as moderately durable (with an average service life of 2-5 years). Similar tests on S. pauciflora at Princess Risborough (U.K.) have indicated that the timber is moderately durable with a service life of 10-15 years (under temperate conditions). The sapwood of dark red meranti is susceptible to dry-wood termite attacks, which may eventually spread to the heartwood. However, an initial invasion of the heartwood is less likely to occur. Untreated timber of S. curtisii was only slightly attacked by marine borers after eight months submergence at Port Klang (Thomas, 1933). Preliminary work done by Oliver & Woods (1957, 1959) have tentatively classified dark red merantias resistant to such attacks.

PRESERVATIVE TREATMENT

The timber is difficult to treat with preservatives. Generally, it was found that all forms of meranti (including dark red meranti) absorb less preservative than kempasand keruing when subjected to identical treatments.  

TEXTURE

Texture is moderately coarse and even, with interlocked grain. 

STRENGTH PROPERTIES

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

Strength Properties of Dark Red 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. acuminata	Green	10,500	54	27.4	2.41	6.3
	Air dry	-	-	-	-	-
S. curtisii	Green	12,800	69	36.3	3.86	7.2
	Air dry	13,900	90	45.4	5.03	8.0
S. pauciflora	Green	12,700	71	37.7	3.45	7.5
	Air dry	-	-	-	-	-
S. platyclados	Green	11,300	58	30.0	2.69	6.3
	Air dry	12,100	77	39.6	4.14	8.7
S. singkawang	Green	10,100	55	31.8	3.03	7.6
	Air dry	11,200	74	38.8	2.97	8.3

  
MACHINING PROPERTIES

It is easy to saw and work and produces a smooth planed surface.

Machining Properties Dark Red 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. acuminata(part only; the darker coloured varieties)	Green	easy	easy	easy	smooth	easy	smooth	-	-
	Air dry	easy	easy	easy	smooth	easy	smooth	easy	moderately smooth
S. curtisii	Green	easy	easy	easy	smooth to slightly smooth	easy	smooth	-	-
	Air dry	easy	easy	easy	moderately smooth	easy	smooth	-	-
S. pauciflora	Green	easy	easy	easy	smooth	easy	smooth	-	-
	Air dry	easy	easy	easy	smooth	easy	smooth	easy	smooth
S. platyclados	Green	very easy	easy	easy	smooth	moderately easy	smooth	-	-
	Air dry	easy	easy	easy	smooth	moderately easy	smooth	easy	smooth
S. singkawang	Green	easy	easy	easy	smooth	easy	rough	-	-
	Air dry	easy	easy	easy	smooth	easy	slightly rough	easy	smooth

NAILING PROPERTY

The nailing property is rated as good.

AIR DRYING

The seasoning properties of some species tested are summarised below:

Species	Time to air dry (months)		Remarks
	13 mm thick boards	38 mm thick boards
S. curtisii	2	3	Fairly fast drying; free from seasoning defects.
S. pauciflora	2.5	4	Fairly fast drying; free from seasoning defects.
S. platyclados	2	4	Fairly fast drying; free from seasoning defects.
S. singkawang	3	5	Fairly slow drying rate; free from seasoning defects.

KILN-DRYING

Kiln Schedule F is recommended. The timber dries rapidly without any degrade.

Kiln Schedule F 

Moisture Content (%)	Temperature (Dry Bulb)		Temperature (Wet Bulb)		Relative Humidity (%) (approx.)
	F	C	F	C
Green	120	48.5	111	44.0	75
60	120	48.5	109	43.0	70
40	125	51.5	109	43.5	60
30	130	54.5	109	43.0	50
25	140	60.0	115	46.0	45
20	155	68.0	124	51.0	40
10	170	76.5	136	58.0	40

 

SHRINKAGE

The shrinkage of some species tested is summarised below:

Species	Shrinkage (%) (Green to air dry)		Remarks
	Radial	Tangential
S. curtisii	2	4.1	High shrinkage
S. pauciflora	1.7	2.9	High shrinkage
S. platyclados	2.1	4.4	High shrinkage
S. singkawang	1.1	3.4	Fairly high shrinkage, especially in the tangential direction.

  

MOVEMENT IN SERVICE

The movement of seasoned timber is classified under Type I and Type II.

DEFECTS

All timbers in the meranti group are liable to be attacked by shot-hole and pin-hole beetles, but the attack is usually not serious in species of dark red meranti. Although most of these attacks take place in the living trees, any delay in extraction after felling may also lead to serious damage. Spongy heart is a common defect in the red meranti group. Timber with this defect is exceptionally brittle and may result in compression failure and the corresponding reduction in strength properties. In a study of logs of dark red meranti and light red meranti from Perak state, about 30 logs of seraya (S. curtisii), over 40 logs of nemesu (S. pauciflora) and more than 100 logs of light red meranti were found to contain varying degree of spongy heart. This presence of spongy heart was less severe and also less spread in dark red meranti than in light red meranti . But large sized logs of dark red meranti (bothseraya and nemesu) tend to rot away at the centre leaving a hollow core with active termite attack on the fringes (Mohd. Alwy, 1961). One prominent feature ofdark red meranti is the presence of exceptionally numerous and conspicuous lines of resin canals, which may be objectional to some user. Small resin pockets are present but they are seldom numerous. One case was noted in which abnormally large horizontal resin canals in S. ovata marred the appearance of the sawn timber.

USES

The timber is suitable for joinery, furniture, high class interior finishing, flooring, decking, panelling, partitioning, mouldings, skirtings, fancy doors, door and window frames and sills, staircase (angle blocks, rough bracket and tread), plywood, railway sleepers, posts, beams, joists, rafters, pallets (expendable type), vehicle bodies (framework, floor boards and planking), ship and boat building (keels, keelsons, framework and general planking), cooling tower (non structural members) and other light constructional works.