- The arjuna tree (Terminalia arjuna) may be best known for its medicinal properties and its importance to the charismatic grizzled giant squirrel, but it plays a special role in the river-forests of Karnataka’s Cauvery Wildlife Sanctuary too.
- A higher number of trees specific to riverine habitats thrive under the canopies of old arjuna trees.
- The soil under these trees’ enormous canopies is also more moist and higher in organic carbon.
- This makes a case to recognize it as a keystone species — one that plays a crucial role in the landscape — and conserve large, old trees.
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- The arjuna is a large, buttressed tree that usually grows along river banks.
- With its interlocking roots and large canopy, does the tree influence the composition of plant communities under it?
- To find out, scientists at Bangalore University noted the plant species growing under the canopy of arjuna trees, as well as in areas without the trees.
- This revealed a higher species diversity (44 species; some like the mahua tree Madhuca latifolia grew only under the canopy of arjuna trees) under these trees, while similar riverine areas without arjuna trees housed only 26 species.
- Areas devoid of the trees also had more species that were not native to riverine stretches.
- Soil in areas under the canopy of the tree had higher organic carbon and moisture contents, probably due to the presence of the large canopy.
- Put together, these factors prove that the arjuna is a crucial tree in the landscape.
- Interestingly, the proposed Mekedatu project — that aims to provide drinking water to Bengaluru — could result in the submergence of numerous old arjuna trees.
- Given that the regeneration of the species is very low (there are very few young arjuna trees or its saplings in the area), this could be a cause for worry, he warned.
