January / February 2018 • Issue 1 • PANELS & FURNITURE ASIA 62 WOOD CLINIC Dear Mr Shim, I have just joined a small carpenter's shop that makes bar counters and stools. However, I do not yet know how to identify wood species. Can you offer some tips on identification? Our bar counters are made using 5-inch thick slabs of rift cut log and there are often large cracks. We use a mixture of ferrous glue and sawdust to fill these cracks. However the patched area tends to bulge after some time (Fig. 1). Can you advise us on these problems? Yours Sincerely, Mr Sarin Indonesia Mr Shim (Shen Yuxin) ASK MR SH IM HOW TO I DENT I FY INDONESIAN TIMBERS AND FILL UP CRACKS A READER'S EMAIL (I) IdenƟfying Indonesian Ɵmbers 1. Hardwood: Annual rings are generally less distinct; cells mainly consist irregular vessels, tracheids, wood rays, parenchymas and fibres. Hardwoods with medium or high density are the most common, although there are also low-density species. 2. SoŌwood: Also known as coniferous timbers, softwood’s annual rings are distinct; cells mainly consist regular-sized tracheids, wood rays and parenchymas. Wood is mostly soft; there are some species that have high density. Only two types of softwood are common in Indonesia: Merkusii pine and Philippine Agathis. 3. Characteristics: Observing the radial, lateral and cross section of the wood can help identify its species. i. Colour: Wood species such as Kapur has a light bluish yellow sapwood and pink heartwood (Fig. 2). ii. Odor: Timber such as kapur smells of camphor when sawn apart. iii. Specific gravity: Belain or Ulin, for instance, has an air-dry density of around 850-1100kg/m 3. iv. Annual ring: Indonesian hardwoods have less distinct annual rings, except a few species such as the lacquer tree (or Rengas). According to the d i st r i bu t i on o f t he ve s s e l s , hardwoods can be divided into diffuse porous hardwood and ring porous hardwood. For example, Dark Meranti and Merbau are ring porous hardwoods. Fig. 1: Glue line showing the patched area bulging out after patching with a mixture of ferrous glue and sawdust. Fig. 2: When Kapur is sawn apart, the sapwood is light bluish yellow, significantly different from the pink heart wood.