Cinchona lost their plants when a wave took them off their ship. The Dutch sent Justus Hasskarl who brought plants that were then cultivated in Java from 1854. The English explorer Clements Markham went to collect plants that were introduced in Sri Lanka and the Nilgiris of southern India in 1860. The main species introduced were "Cinchona succirubra" or red bark, as its sap turned red on contact with air, and "Cinchona calisaya". The alkaloids quinine and cinchonine were extracted by Pelletier and Caventou in 1820. Later two more key alkaloids, quinidine and cinchonidine were identified and it became a routine
Bark pocket indicator of air pollutants during which the time they formed. They can be used to monitor heavy metals such as lead and copper, as dust or other matter deposited on the bark at the time of formation is still present. One study analysed the amount of polycyclic aromatic hydrocarbons (PAHs) present in bark pockets as a historical record of air quality, possible due to the interaction between PAHs and lipids in the bark. Bark pocket Bark pockets can be formed by inosculation, formation of a tree fork, encapsulation of a branch, joining together of an uneven trunk, or encapsulation of