Physical properties of planted kelempayan (Anthocephalus chinensis) [Malaysia]
1992
Mohd Hamami Sahri (Pertanian Malaysia Univ., Serdang, Selangor (Malaysia). Faculty of Forestry) | Ismail Hj Jusoh
Six Kelempayan trees (Anthocephalus chinensis) were felled and sampled at three radial positions and at five different height levels to determine the wood specific gravity, green moisture content, and shrinkage properties. Two 2-metre bolts were also obtained to assess their drying characteristics and defects. Variation between and within trees indicate that all properties measured were statistically significant. Overall average specific gravity was 0.36 and there were significant differences between the specific gravities of the three radial positions and height levels. Specific gravities tend to increase from pith outwards and with height. Average green moisture content was about 175 and a reverse trend was obtained; decreasing from pith outwards and with height. The average means of tangential, radial, longitudinal and volumetric shrinkages were 6.46, 3.28, 0.47 and 9.90 respectively. Generally, innerwood (near pith) has a higher tangential and longitudinal shrinkage whilst middlewood has the least volumetric shrinkage. No general vertical pattern was observed for all types of shrinkages, although tangential shrinkage appears to decline with height. Tangential and radial movement (from 17 to 12 moisture contents) were also observed. Tangential movement was found to be about twice that of radial movement, i.e. 1.7 and 0.9, respectively, and showed no significant difference within and between trees. The average period of drying (in the forced-air dryer) down to 12-14 moisture content was 25 days for the 25 mm thick boards with minimal traces of drying defects such as surface cheeks, bow, spring and twist.
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Эту запись предоставил Universiti Putra Malaysia