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Frankincense, also called olibanum, is an aromatic resin used in incense and perfumes, obtained from trees of the genus ''Boswellia'' in the family Burseraceae, particularly ''Boswellia sacra'' (syn: ''B. carteri'', ''B. bhaw-dajiana''), ''B. frereana'', ''B. serrata'' (''B. thurifera'', Indian frankincense), and ''B. papyrifera''. The English word is derived from Old French "franc encens" (i.e., high quality incense).〔>〕 There are four main species of ''Boswellia'' that produce true frankincense. Resin from each of the four is available in various grades. The grades depend on the time of harvesting; the resin is hand-sorted for quality. ==Description== Frankincense is tapped from the scraggy but hardy trees by slashing the bark, which is called striping, and allowing the exuded resin to bleed out and harden. These hardened resins are called tears. There are several species and varieties of frankincense trees, each producing a slightly different type of resin. Differences in soil and climate create even more diversity of the resin, even within the same species. ''Boswellia sacra'' trees are considered unusual for their ability to grow in environments so unforgiving that they sometimes grow out of solid rock. The initial means of attachment to the rock is unknown, but is accomplished by a bulbous disk-like swelling of the trunk. This growth prevents it from being ripped from the rock during violent storms. This feature is slight or absent in trees grown in rocky soil or gravel. The trees start producing resin when they are about eight to 10 years old.〔(【引用サイトリンク】title=Omani World Heritage Sites )〕 Tapping is done two to three times a year with the final taps producing the best tears due to their higher aromatic terpene, sesquiterpene and diterpene content. Generally speaking, the more opaque resins are the best quality. Fine resin is produced in Somalia, from which the Roman Catholic Church purchases most of its stock.〔(BBC.co.uk )〕 Recent studies have indicated that frankincense tree populations are declining, partly due to over-exploitation. Heavily tapped trees produce seeds that germinate at only 16% while seeds of trees that had not been tapped germinate at more than 80%. In addition, burning, grazing, and attacks by the longhorn beetle have reduced the tree population. Conversion (clearing) of frankincense woodlands to agriculture is also a major threat. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「frankincense」の詳細全文を読む スポンサード リンク
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