| Publish Year：1996 |
Author：Jung-lei Tang |
| Keyword：wood variation, mechanical property, native wood in taiwan, hardwood, formosa alder, logn glans oak, formosan michelia. |
| Wood is a biological material and composed of cells of various shapes and sizes. These and the associated changes in the anatomical structure of wood play a major role in the property variations, such as between and within species, growth directions, etc., which have a great effect on the wood utilization. The main purpose of this study is to examine the within trunk variation in the wood strength properties of three important hardwood species native to Taiwan. They are Alnus formosana or Formosan Alder (FA), Cyclobalanopsis longinux or Long Glans Oak (LGO), and Michelia formosana or Formosan Michelia (FM). One tree with straight trunk and no signs of abnormal wood for each species was chosen. The measured DBH values were 60.5, 44.0, and 78.0 cm for FA, LGO, and FM, respectively. Small, clear and streight grained specimen was made from the wood taken from three different heights of each smaple tree trunk. It was found that the MOR of FM wood was stronger than that of LOG. The MOR of FA wood was the weakest among the three. For specific gravity and compression strength, they were shown in decreasing order as LGO, FM, and FA. No consistent variation patterns were found for various strength properties when comparing the results obtained from the different locations, i.e., north, south, east, and west aspect, of the cross section areas at the selected heights of a trunk. The wood strength for FM and LGO showed a decreasing trend with increasing in the trunk height. The reverse was true, however, for FA. From pith toward sapwood, a gradual increase in the strength properties was noted. In general, FA showed a faster rate of growth and larger variation than those of the other two hardwood species tested. |
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