Girdling of invasive tree species taken up in Nagarhole

BENGALURU:  The spread of invasive species of Cassia spectabilis (spectacular cassia) in the contiguous wildlife areas of Niligiri Biosphere Reserve in Karnataka, Kerala and Tamil Nadu has been posing a serious threat to the very survival of prey species and ultimately, the tigers. In a bid to stop the invasion of these flowering trees in Nagarhole Tiger Reserve, the state Forest Department has taken up ‘girdling’ of this species in a few patches — wherever it has grown to large proportions — on an experimental basis. With activists reporting instances of trees being girdled in Nagarhole and lodging a complaint with the PCCF, forest officials have clarified that girdling of spectabilis was taken up as it was the only method to arrest the fast spread of this species. 

What is girdling? Girdling involves complete removal of a strip of bark around the circumference of the tree. This portion contains both food vessels and part of water transporting vessels. According to tree experts, when the main trunk of a tree is girdled, the whole tree will ultimately die. Tree species that have been girdled can be observed between Kalhalla and Murkal in the Nagarhole Wildlife Range after Nittur as one enters the tiger reserved from Hunsur town. The decision to girdle these flowering trees was taken up by Manikandan, the late director of Nagarhole.

Tree Committee member Vijay Nishanth, who lodged a complaint with the PCCF adds, “After Lantana, this invasive species is a threat as it does not allow any other species to grow. We fully support the Forest Department’s efforts to curb the growth of this species. But I wish they had put this information in the public domain.” Meanwhile, a senior forest official clarified and said this species, which regenerates very fast, is spread across both Nagarhole and Bandipur

Cassia spectabilis
A medium to large tree from tropical America, spectabilis is listed in the ‘Global Compendium of
Weeds’ as an environmental weed,garden thug and naturalised weed.The species is extremely fastgrowing,
flowers profusely andsprouts readily when cut. It stifles native flora and affects the food 
availability of ungulates, thereby,increasing man-animal conflict.