Mempisang wood

 

INTRODUCTION

The Standard Malaysian Name for the timber of the family Annonaceae. Vernacular names applied include akau (Sarawak), antoi (Peninsular Malaysia), jangkang (Peninsular Malaysia), karai (Sabah and Sarawak) with various epithets, kepayang babi (Sarawak), mangitan (Peninsular Malaysia), manitan (Peninsular Malaysia) and pisang-pisang (Peninsular Malaysia and Sabah). Major species include Alphonsea curtisii, A. elliptica, A. johorensis, A. maingayi; Cyathocalyx pruniferus, C. sumatranus; Mezzettia parviflora; Mitrephora maingayi, M. vulpina; Monocarpia euneura; Platymita siamensis; Polyalthia glauca, P. hypoleuca, P. sclerophylla, P. sumatrana; Xylopia ferruginea, X. fusca and X. stenopetala. The sapwood is normally not differentiated from the heartwood, which is light yellow-white or light yellow-brown, often with a green tinge.

Also known as Mempisang (Brunei); Mako (Fiji); Debdaru, Gauri and Nedunar (India); Banitan putih, Jongkong, Kepayong babi, Langolia maeto, Loera poete, Mahabai, Mandjat, Oenrolia wone, Salak, Semukau padi, Suluh, Tapal madu, Tepis and Uras lemah (Indonesia); Taw and Tawsagasein (Myanmar); Bolon, Dalinas, Kalai and Yellow Lanutan (Philippines); Netawa (Sri Lanka); and An-phong (Vietnam).

DENSITY

The timber is a Light Hardwood with a density of 370-975 kg/m3 air dry, although the majority of the timbers fall within the range of 515-720 kg/m3 air dry.

NATURAL DURABILITY

Mempisang has been classified as non-durable under exposed conditions in Malaysia (Wong, 1982). The above classification is mainly based on the findings by Jackson (1965) who tested the timber Monocarpia marginalis (formerly known as Cyathocalyx maingayi) under natural conditions and the timber was completely destroyed in slightly more than a year. Mohd. Dahlan et. al., (1987) tested the natural durability of three species of mempisang, namely Monocarpia marginalis, Xylopia fusca and Mezzettia leptopoda and they were found to be not durable. Desch (1957) reported that in Sumatra, the timber of Mezzettia leptopoda or a related species, when used for planks under cover or protected from rain are fairly durable. In India, Pearson et al. (1932) described the timber of Polyalthia as fairly durable for internal work and not very susceptible to insect and fungal attacks.

PRESERVATIVE TREATMENT

The timber is very amenable to preservative treatment.

TEXTURE

Texture is rather coarse and uneven due to the presence of the extremely large rays.

STRENGTH PROPERTIES

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

Strength Properties of Mempisang  

Species	Test Condition	Modulus of Elasticity(MPa)	Modulus of Rupture (MPa)	Compression parallel to grain (MPa)	Compression perpendicular to grain (MPa)	Shear strength(MPa)
Mezzettia leptopoda	Green	12,500	59	34.5	2.29	6.6
	Air dry	14,800	80	51.0	4.62	8.0
Monocarpia marginalis	Green	13,000	66	36.3	2.91	7.4
	Air dry	13,800	85	46.0	4.07	8.4
Xylopia fusca	Green	12,100	57	26.5	3.93	7.0
	Air dry	13,400	80	41.5	3.65	11.3

MACHINING PROPERTIES

The timber is easy to work and plane and the surface produced may not be perfectly smooth. Boring is easy but the surface obtained may be rough. Turning is easy and a smooth finish may be achieved.

Machining Properties of Mempisang (M. marginalis) 

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	easy	easy	easy	moderately smooth	easy	rough	–	–
Air dry	easy	easy	easy	moderately smooth	easy	rough	easy	smooth

NAILING PROPERTY

The nailing property is rated as poor.

AIR DRYING

The seasoning properties of the timber vary according to the species and are summarised below:

Species	Time to air dry (months)		Remarks
	13 mm thick boards	38 mm thick boards
Mezzettia parviflora	1.5	2	Very fast drying; moderate cupping and insect and fungal attack.
Monocarpia euneura	4	5	Fairly slow drying; moderate splitting; slight end-checking and surface-checking.
Xylopia fusca	3	5	Fairly slow drying; moderate cupping, bowing and staining; slight end-checking and insect attacks.

 

 

 

 

 

 

 

KILN-DRYING

Kiln Schedule H is recommended. However, the schedule is based on the test carried out on the species of Mezzettia parviflora, the density of which is about 670 kg/m3 air dry. When dealing with the heavier varieties of mempisang, e.g. Alphonsea elliptica (density: 975 kg/m3) and Polyalthia rumphii (density; 805-815 kg/m3), due care should be taken to use a milder schedule to prevent the occurence of drying defects.

Kiln Schedule H

Moisture Content (%)	Temperature (Dry Bulb)		Temperature (Wet Bulb)		Relative Humidity (%)
	� F	� C	� F	� C
Green	135	57.0	127	53.0	80
50	135	57.0	126	52.0	75
40	140	60.0	126	52.0	65
30	150	65.5	129	54.0	55
20	170	76.5	136	58.0	40

SHRINKAGE

The shrinkage of some species is summarised below: 

Species	Shrinkage (%) (Green to air dry)		Remarks
	Radial	Tangential
Mezzettia parviflora	4	4.4	Very high shrinkage.
Monocarpia euneura	1.5	2.7	Moderate shrinkage.
Xylopia fusca	2.8	4.5	Very high shrinkage.

 

 

 

 

USES

The timber is suitable for general light construction, plywood, pencil, match boxes and splints, ornamental items, bentwood, packing cases and crates. The heavier species can be used for flooring, joists (light construction), railway sleepers, ship and boat building (masts, spars, oars and helms), tool handles (non impact) and cooling tower (non-structural).