Eucalyptus trees are a familiar sight across Karnataka, their silvery leaves lining Bengaluru’s streets and their oils often providing relief during colds and illnesses. Introduced from Australia, they were once celebrated as a source of timber and economic promise. Yet beneath this appealing facade lies a significant challenge. These trees, alongside other invasive species such as Prosopis juliflora and Lantana camara, are transforming India’s grasslands, depleting water resources, and displacing wildlife like blackbucks, lesser floricans, and Great Indian Bustards.
The British introduced eucalyptus to India in the 1840s, planting it in the Nilgiris for rapid timber production. Karnataka continued this practice in the 1960s, 1970s, and 1980s, converting vast areas into plantations. Today, the Karnataka Forest Department is reevaluating this approach, assisted by organisations such as Ashoka Trust for Research in Ecology and the Environment (ATREE), promoting Open Natural Ecosystems (ONEs) to demonstrate that grasslands are not barren wastelands but vibrant habitats that have sustained biodiversity and livelihoods for millennia.
Eucalyptus plantations are often at the centre of environmental controversies due to their significant ecological impacts. These fast-growing trees are known for their high-water demand, which can severely reduce groundwater recharge and alter local hydrological cycles. Studies highlight their allelopathic properties, which inhibit the growth of neighbouring plants and microorganisms, leading to soil nutrient depletion and reduced fertility. Eucalyptus plantations can also displace native vegetation, undermining biodiversity and replacing conventional forests with monocultures that offer limited ecological benefits.
Researchers from ATREE investigated the decline in surface flows into the Thippagondanahalli Reservoir, once a key source of Bengaluru’s drinking water. Their findings indicated that groundwater pumping and the expansion of eucalyptus plantations are one of the primary drivers of this loss. Fortunately, viable solutions exist to address this issue collaboratively.
During a recent visit to the Ranebennur Blackbuck Sanctuary, our team observed extensive encroachment of eucalyptus into grasslands, a critical habitat for blackbucks and rare bird species like the lesser florican and Great Indian Bustard. This invasion restricts the growth of native grasses essential for these species’ survival. Compounding the issue, other invasive species are spreading rapidly, further stifling biodiversity and degrading ecosystems. These combined pressures highlight the urgent need for sustainable management practices to protect grasslands and their unique wildlife.
Removing eucalyptus and other invasives also presents economic potential along with ecological benefits. The vast areas currently covered by eucalyptus can support livelihoods through their phased removal and usage for timber, which could take years given the scale of the plantations. At ATREE’s Bagepalli field site, researchers are offering a practical solution by converting invasives like Prosopis juliflora into biochar, a carbon-rich material that enhances soil fertility. Distributed free to farmers, this biochar is increasing agricultural productivity. Beyond local benefits, biochar holds promise as a tradable commodity for carbon credits, providing the potential for Karnataka to monetise carbon sequestration while restoring its landscapes.
The next step involves replanting native, palatable grass species to revitalise faunal diversity, as they provide essential forage for blackbucks, bustards, and other species. Coupled with biochar’s soil-enhancing properties, this approach creates a sustainable cycle: removing invasives improves water retention, replanting natives boosts biodiversity, and biochar supports agriculture. The Karnataka Forest Department has been actively clearing eucalyptus from sanctuaries since 2011, laying the groundwork for such efforts.
Karnataka’s stance on eucalyptus reflects a complex balance. In 2017, the state banned its cultivation, recognizing its toll on groundwater and ecosystems. However, a 2019 High Court stay, prompted by farmers’ concerns over livelihoods, paused enforcement. In 2024, the Department of Large and Medium Industries formed a committee to explore reintegrating eucalyptus, though its report remains pending. This deliberation suggests a willingness to adapt. The United Nations Convention to Combat Desertification (UNCCD) offers guidance here, advocating sustainable land management over water-intensive monocultures, a framework Karnataka could leverage to refine its strategy, especially relevant in the current UN Decade on Ecosystem Restoration.
The challenge extends beyond Karnataka. Tamil Nadu continues to clone eucalyptus for timber; and India’s forest cover statistics obscure reality by classifying plantations as forests, following a recent legislative amendment. This practice contradicts the guidelines laid out in the T. N. Godavarman judgment.
A Tamil Nadu State Planning Commission report mentions that only 10 invasive alien species, out of the 330 species that are known to be invasive in India, have inflicted economic damages exceeding Rs 10.5 lakh crore nationwide in the last 60 years. Yet, solutions like biochar and carbon credits present a pathway to offset these costs, aligning ecological restoration with economic incentives.
The question remains: how do we chart a different course? The answer lies in science, policy, and collaboration. The Karnataka Forest Department’s keen interest in removal efforts, alongside projects like ATREE’s Bagepalli initiative, provides a strong starting point. International conventions like UNCCD also offer solid frameworks to learn from. We need a scientific approach to assess the issue, grounded in strong principles, clear definitions and assessments; and implementable laws and policies. By clearing invasives, replanting native grasses, and optimising the use of biochar, Karnataka can protect its grasslands, support farmers, and redefine forest cover accurately.
Dr Abi Tamim Vanak, Director of the Centre for Policy Design at ATREE, estimates that ONEs, which encompass grasslands, savannahs, shrublands, deserts, and rocky outcrops span more than 10 per cent of India’s geographical area. That’s larger than the combined size of the Netherlands, New Zealand, Bhutan and the Maldives. These ecosystems, with grasslands as a vital cornerstone, form the backbone of India’s biodiversity and sustain millions of rural livelihoods.
Development and conservation need not be at odds. With the Forest Department’s dedication and collaboration with key stakeholders, we can convert the eucalyptus-dominated past into a resilient, balanced future. India has the opportunity and capability to safeguard its rich ecological heritage while forging a path where prosperity and nature thrive in harmony, setting a global example of coexistence. Let us come together this World Water Day and prioritize dynamic and long-lasting solutions for our joint futures.
Sachin Pernacca Sashidhar is a policy analyst at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru
Views expressed are the author’s own and do not necessarily reflect that of Down To Earth.