Harvesting and yield

Harvesting and yield

    By judging the amount of vegetative growth, the trees are coppiced when they are 6 to 8 years old.
    Coppicing involves pruning the trees at a height of 5 cm (2 inches) from the ground-level.
    The leftover stump regenerates to produce a large number of shoots, but only two or three of these are retained and allowed to grow further. The rest of the coppices are removed.
    A second coppicing is done 8-10 years after the first coppicing, where only about 2 to 3 shoots are left to grown further.
    The plants are uprooted in the 30th year when their vigor declines.
    The major harvest are obtained at the time of the first two coppicing and only little yield of bark is obtained from the dead and drying trees and pruning.

    Harvesting and Yield

    The first set of yields is obtained in the third year after planting.
    The bark is separated from the coppices by beating it with a mallet and is then peeled by hand or a knife.
    The peeled bark should be dried immediately to prevent the loss of alkaloids, preferably in the shade.
    In rainy weather, drying is done in special sheds or by means of artificial heat.
    In well-established plantation, drying is done in well-regulated ovens.
    For this purpose, hot air ovens, regulated by 700C, are employed.
    The long, strips of bark are cut into small pieces and fed into the upper end of a long, slightly inclined, rotating, cylindrical oven.
    The dried product contains 10% moisture; the dried bark is then packed in gunny bags.
    The dried bark is called ‘Druggists’ bark (quinine content 1.8-2%) in trade.
    During the first two coppicing, a yield of 4000 kg of dry stem bark per hectare is obtained. At the final stage of uprooting the tree, the yield of the bark may be about 6000 kg/ha.

    Isolation of Quinine
    The alkaloids are extracted from the powdered bark.
    Quinine is isolated from the total alkaloids of the bark as quinine sulphate.
    The commercial preparations contain cinchonidine and dihydroquinine also, and the quinine may be purified by recrystallizaiton to constant specific rotation.
    The crystalline, efflorescent trihydrate is a white, odourless, intenselybitter, micro-crystalline powder.



Last modified: Friday, 22 June 2012, 5:27 AM