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Hevea brasiliensis : ウィキペディア英語版 | Hevea brasiliensis
''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, or, most commonly, the rubber tree, is a tree belonging to the family Euphorbiaceae. It is the most economically important member of the genus ''Hevea''. It is of major economic importance because the milky latex extracted from the tree is the primary source of natural rubber. ==Rubber tree plantation==
In the wild, the tree can reach a height of up to . The white or yellow latex occurs in latex vessels in the bark, mostly outside the phloem. These vessels spiral up the tree in a right-handed helix which forms an angle of about 30 degrees with the horizontal, and can grow as high as 45 ft. In plantations, the trees are generally smaller for two reasons: 1) Trees grow more slowly when they are tapped for latex, and 2) trees are generally cut after 30 years because latex production declines as trees age, and they are no longer economically viable. The tree requires a tropical or subtropical climate with a minimum of about 1200 mm/yr of rainfall, and without frost.〔 If frost does occur, the results can be disastrous for production. One frost can cause the rubber from an entire plantation to become brittle and break once it has been refined.
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「Hevea brasiliensis」の詳細全文を読む
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