Anatomical Response of Regenerated Bark in Terminalia arjuna (Roxb.) Wight & Arn.

Terminalia arjuna is a large tropical tree whose both original and regenerated bark is commercially exploited for medicinal purpose mainly to cure cardiac diseases. For sustainable supply of Arjuna bark, the regenerated bark of tree is usually harvested within 18–24 months with controlled wounding at different girth classes. During course of investigation, it was found that the biomass and rigidity of regenerated bark was higher than original bark in each girth-class of tree. To explore the reason for higher biomass and rigidity in the regenerated bark of Arjuna, a comparative anatomical investigation was carried out between original and regenerated bark from randomly selected trees of middle girth-class (50-75cm). Results showed that there was significantly higher proportion of phloem fibres and ray cells and lower proportion of sieve tubes in regenerated bark in comparison to original bark. Most of the fibre dimensions and ray parameters varied between original and regenerated bark and also between first and second harvest of the regenerated bark. The wounded tree gives first preference to the protection of the injured bark from surroundings rather than food conduction through sieve tubes.