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Mengkulang Wood: Characteristics and Uses

Introduction
Mengkulang is the standard Malaysian name for the light timber derived from the Heritiera species (Sterculiaceae family). This wood is known by various vernacular names across Malaysia, including Mengkulang (Peninsular Malaysia), Jambu Keluang (Melaka), Kembang (Sabah), Melabu (Sarawak), and Melima (Peninsular Malaysia). The main species include H. albiflora, H. aurea, H. borneensis, H. globosa, H. javanica, H. simplicifolia, and H. sumatrana. The sapwood of Mengkulang is typically lighter in color than the heartwood, which ranges from red to red-brown or dark red-brown.

#### International Names
Mengkulang is also known by other names in different regions:
- *Australia*: Red or Brown Tulip Oak
- *Cambodia*: Bey Samlek and Don Chem
- *Brunei*: Mengkulang
- *India*: Sundri
- *Indonesia*: Mengkulang, Palapi, and Teraling
- *Laos*: Hao
- *Myanmar*: Kanazo
- *Philippines*: Lumbayao
- *Thailand*: Chum-praek and Chumprak
- *Vietnam*: Huynh

#### Density
Mengkulang is classified as a Medium Hardwood with an air-dry density ranging from 625 to 895 kg/m³.

#### Natural Durability
While Mengkulang is not durable when in direct contact with the ground due to susceptibility to termite damage and fungal infestation, it performs well in dry, well-ventilated environments free from termite exposure. Treated timber has shown serviceable durability, lasting up to 13 years in testing after treatment with preservatives.

#### Preservative Treatment
Mengkulang timber is moderately receptive to preservative treatments and is classified as "average" in treatability.

#### Texture and Grain
The texture of Mengkulang wood is slightly to moderately coarse but even. The grain is typically straight to shallowly interlocked, offering a smooth finish when properly worked.

#### Strength Properties
Mengkulang timber falls into Strength Group B (Engku, 1988b) or SG 5 (MS 544:Part 2:2001), making it suitable for various construction and furniture applications.

| Species | Test Condition | Modulus of Elasticity (MPa) | Modulus of Rupture (MPa) | Compression parallel to grain (MPa) | Compression perpendicular to grain (MPa) | Shear strength (MPa) |
| --- | --- | --- | --- | --- | --- | --- |
| H. javanica | Green | 10,600 | 68 | 31.8 | 4.21 | 9.9 |
| H. simplicifolia | Green | 13,700 | 75 | 37.8 | 3.86 | 8.2 |
| H. simplicifolia | Air dry | 15,990 | 91 | 52.1 | 5.38 | 10.8 |

#### Machining Properties
Mengkulang is difficult to saw and slightly challenging to plane, but it can yield a smooth finish with proper techniques.

| Species | Test Condition | Sawing | Planing | Boring | Turning |
| --- | --- | --- | --- | --- | --- |
| H. javanica | Green | Difficult | Slightly difficult | Smooth | Slightly difficult |
| H. javanica | Air dry | Difficult | Slightly difficult | Moderately smooth | Slightly rough |
| H. simplicifolia | Green | Slightly difficult | Easy | Smooth | Moderately smooth |
| H. simplicifolia | Air dry | Difficult | Easy | Smooth | Slightly rough |

#### Nailing Property
Mengkulang has good nailing properties, making it suitable for construction and carpentry applications.

#### Air Drying
Mengkulang timber seasons fairly rapidly, with slight cupping, end-checking, and surface-checking being the primary defects. Thinner boards (13 mm) take approximately 2 months to air dry, while thicker boards (38 mm) take about 3 months.

#### Kiln-Drying
Kiln Schedule D is recommended for drying Mengkulang. Boards with a thickness of 25 mm take around 7 days to dry.

| Moisture Content (%) | Temperature (Dry Bulb) | Temperature (Wet Bulb) | Relative Humidity (%) |
| --- | --- | --- | --- |
| Green | 105°F (40.5°C) | 101°F (38.0°C) | 85% |
| 60% | 105°F (40.5°C) | 99°F (37.0°C) | 80% |
| 40% | 105°F (40.5°C) | 96°F (35.5°C) | 70% |
| 35% | 110°F (43.5°C) | 97°F (36.0°C) | 60% |
| 30% | 115°F (46.0°C) | 97°F (36.0°C) | 50% |
| 25% | 125°F (51.5°C) | 101°F (38.0°C) | 40% |
| 20% | 140°F (60.0°C) | 105°F (40.5°C) | 30% |
| 15% | 150°F (65.5°C) | 112°F (44.5°C) | 30% |

#### Shrinkage
Mengkulang timber exhibits high shrinkage, with radial shrinkage averaging 1.5% and tangential shrinkage averaging 3.4%.

#### Defects
Mengkulang logs are generally free from defects, making them ideal for high-quality applications.

#### Uses
Mengkulang timber is versatile and suitable for various applications, including:
- Medium construction
- Decorative works
- Superior joinery and cabinet making
- Interior finishing and panelling
- Mouldings and general planking
- Furniture and plywood
- Flooring and decking
- Staircase components (angle block, rough bracket, baluster, handrail, etc.)
- Vehicle bodies and shipbuilding
- Railway sleepers and piling
- Cooling tower structural members
- Door and window frames and sills
- Posts, beams, joists, and rafters
- Telegraphic and power transmission posts and cross arms