SULTAN BATHERY: Muthanga has emerged as a model site in Kerala’s fight against senna spectabilis (manjakonna), an invasive South American tree species that has severely disrupted Wayanad’s forest ecosystem. The forest department’s ambitious eradication programme, launched in 2025 across 150 hectares in Muthanga and Tholpetty, has already restored 80 hectares of forest land in Muthanga, marking a significant ecological achievement.
Forest officials view the project as a major step towards reviving native biodiversity and restoring the region’s ecological balance. The department now plans to extend the initiative to the remaining affected areas.
“Senna spectabilis had spread aggressively across the Muthanga and Tholpetty forests, posing a serious threat to the natural ecosystem,” said South Wayanad divisional forest officer Ajith K Raman. “The species suppressed native vegetation, altered habitat conditions and contributed to groundwater depletion. As water and food sources declined within the forest, wild animals increasingly ventured into human settlements, leading to a rise in human-wildlife conflicts,” he said.
To tackle the problem, the forest department entered into an agreement with Kerala Paper Products Limited (KPPL), under which the company harvested approximately 5,000 metric tonnes of senna wood for use in paper pulp production.
“The project initially required KPPL to pay Rs 350 per metric tonne of senna wood removed. Later, the agreement was revised to focus on complete eradication measures, including debarking the lower portion of the trees and maintaining cleared sites to prevent regrowth,” Raman said.
According to him, the collaboration has enabled the successful removal of senna spectabilis from 80 hectares of forest land along the state highway in Muthanga. Native tree species have since been planted in the restored areas to accelerate ecological recovery.
Muthanga range officer K K Sundharan said long-term monitoring remains crucial because of the species’ exceptional ability to regenerate.
“After felling the trees, KPPL workers remove the bark around the root zone and cover it with soil to prevent regrowth.
The company is responsible for monitoring the sites for six months. However, that period alone is not sufficient because senna spectabilis has a very high regeneration rate, even when the tree appears dead,” he said.
Sundharan noted that forest guards and watchers conduct regular inspections to identify and destroy new saplings. “Apart from their routine duties, they continuously patrol the forest to ensure that the species does not re-establish itself,” he added.
While the eradication programme covers around 150 hectares across Muthanga and Tholpetty, progress has varied between locations. “In some areas the project has lagged due to insufficient follow-up measures. In Muthanga, however, we have ensured strict monitoring, which has helped prevent regrowth,” Sundharan said.
The ecological significance of the project extends beyond the removal of an invasive species. Introduced during social forestry programmes in the 1980s, senna spectabilis was promoted as an ornamental tree because of its bright yellow flowers. Saplings were widely distributed and planted across forest landscapes. Over time, the species escaped cultivation and spread rapidly through Wayanad’s forests.
Its dense growth suppressed native plants, reduced biodiversity and altered natural forest regeneration. Forest officials say the invasion also affected groundwater availability, further stressing wildlife habitats and contributing to increased human-animal encounters.
The restoration of 80 hectares in Muthanga is now being viewed as a key milestone in ecological recovery, offering a model for invasive species management and forest restoration efforts across Kerala and other South Indian states grappling with senna invasion.
5,000 tonnes removed
Senna spectabilis (manjakonna), an invasive South American tree species has severely disrupted Wayanad’s forest ecosystem
To tackle the problem, the forest department entered into an agreement with Kerala Paper Products Limited, under which the company harvested approximately 5,000 tonnes of senna wood for use in paper pulp production