Analysis | In Bengaluru's Landscape, Paper Mulberry Menace Grows Beyond Control

The invasive plant that releases allergens polluting the air while destroying native species in the garden city, writes Anubha Jain.

Paper Mulberry originated from East Asia, viz., China, Japan, and Mongolia. It was enriched for making bark tapa cloth and paper. For urban forestry it came to India in the 1880s and for the last 25 years, the plant has been invading the garden city of 'Bengaluru'. It initially grew in the core zones of the city and is now spreading to the periphery and open spaces of the city. In Bengaluru, 30% of the greenery is made up of paper mulberry groves.

Extensively spreading in the wide-open areas of Bengaluru, Paper Mulberry botanically known as Broussonetia papyrifera is an invasive and highly allergic plant. In Taiwan, Pakistan, and the US the tree is considered highly allergic.

Owing to people's unawareness of its adverse effects, the plant's greenery captivated the masses and made it famous as an ornamental tree. People aren’t much aware of the consequences of this root sucker plant that can kill native flora within no time. Cutting the tree is also harmful as it produces a great amount of milky latex, so it becomes creepy to cut the tree and the sticky juice is also not good for the eyes and skin as well.

Numerous experts express discontent regarding Bengaluru's preference for exotic species, including Tabebuia and Jacaranda. The trees that are popularly referred to as the blossoms of Bengaluru are predominantly species that have been introduced from other countries or continents. An environmentalist and retired forest officer AN Yellappa Reddyin a candid conversation stated that the native species, mainly those with medicinal values have disappeared from the landscape of the city. In contrast, the exotic species invaded. There is no monitoring of the situation where urbanisation has led to the import of invasive plants.

PhD holder in Forest Botany from FRI Dehradun NM Ganesh Babu, Associate Professor, Transdisciplinary University, a Bengaluru-based private university in an interview said there are male and female Paper Mulberry trees. Male trees produce an enormous amount of pollen and female trees produce fruits. Both the trees are vigorous. The tree gives fruits every six months and pollen from its large inflorescences is considered highly allergic and showed increased asthma symptoms.

Ganesh sadly said that the Bruhat Bengaluru Mahanagara Palike (BBMP) without seeing the ill effects has been planting wrong non-native species and exotic flowering plants like Paper Mulberry and Conocarpus lancifolius in the city. This cannot be done at the cost of human and animal health. It causes colds, coughs, asthma, and allergies among humans. This also spoils the ecosystem. The city administration does not consider what to plant where. The Gujarat government banned the planting of Conocarpus trees in January 2024. The reason cited was “the adverse impacts on the environment and human health”.

Sridhar Punathi, IFS Retired and former Principal Chief Conservator of Forests (Head of Forest Force) said that Bengaluru is 3,000 sq. ft. above sea level, and conducive to planting, with the right temperature, rainfall, and water availability, allowing many species, including those in the Western Ghats, to grow here.

Ganesh further said, "For the last 30 years, our organisation has been revitalising local medicinal native plants. Ayurvedic medicines are based on native medicinal flora." He disappointedly stated, "For over 20 years local flora has been vanishing. And in the coming time, as resources are depleted due to exploitation and illegal/informal trade, we won't get native flora for Ayurved practice."

Professor K. Ravikumar, a professional field Botanist, talked with me about this ornamental tree and said that around 75 years ago the tree was cultivated for decorative and ornamental purposes in the gardens and avenues for its attractive orange-yellow fruits and broad leaves. Now it is occupied in almost all Bengaluru city with excessive numbers and undesirably spreading all over.

The topsoil retains all micronutrients and growing these kinds of exotic trees will surely erode the soil nourishment. Ravikumar stated, "We have a natural ecosystem and we should grow more Indigenous trees and native plants which are available in our forests". He further added that this plant produces an enormous amount of pollen grains in the city which causes pollen allergy to the city dwellers.

He remarked that this will spread so fast by means of root suckers and said that this might have been introduced for testing low-quality paper and manufacture of and pulp industry. Though it has attractive fruits, avifauna seldom feed on it. Disappointed with the current scenario he sadly stated, "It's ironic that today the natural equilibrium has been disturbed and changed and indigenous plants are replaced exorbitantly with exotic ornamental plants."

Chaithrika Hegde, an Ayurvedic practitioner,said, "The paper mulberry tree is seen in a huge population in the entire city of Bengaluru. This tree species tends to grow together in large numbers in the same place and these trees don't allow other plants to grow. And therefore, no other plant can be seen near Paper Mulberry trees. Like, it is growing more than 100 in number, especially in Bengaluru's Sankey tank and the Palace ground areas."

She further said that they create pollen allergies, especially trigger asthma and cause urticarial rashes. "People are unaware of its side effects. So disappointed to see that environmentalists too are not coming forward to stop the growing population of Paper Mulberry," she added.

Senior officials of BBMP Forest Cell said, “We have noticed the plants in several places and will take necessary corrective action.”

Yellappa Reddy stressed that a committee of experts should assess the situation and issue directions on the plants permitted to be grown in a particular landscape.

In the end, Paper Mulberry is an invasive plant and shortly, the city will face the threat. Hence, with immediate corrective measures the plant needs to be replaced with native saplings. The introduction of non-native plant species poses a significant risk to local ecosystems and economic growth. Consequently, it is essential to implement proactive strategies to identify and tackle the problem of invasive alien plants, as early intervention is expected to be more economically viable than managing and eradicating them after they have established themselves.