Eucalyptus Plant: A Resourceful Ally or Environmental Foe?

Eucalyptus, a fast-growing tree species originally from Australia, has been widely planted worldwide for its commercial value. It’s a genus of over 700 species of flowering trees and shrubs, is widely recognized for its economic and medicinal benefits. In addition, particularly to tropical and subtropical regions in globally. However, its natural habitat has sparked debates about its ecological impact, branding it alternately as a valuable resource and an environmental threat. This article explores the dual nature of eucalyptus cultivation and its implications for sustainable development.

Eucalyptus is a major source of timber, pulp, and essential oils. Its fast growth and adaptability to various climates make it ideal for commercial forestry. Eucalyptus plantations are highly profitable compared to other crops, providing higher income and a stable market even in remote areas (Dey et al., 2022). Eucalyptus timber is used in construction, furniture, and as fuelwood, while its pulp is a cornerstone of the paper industry. Due to its rapid growth rate, eucalyptus can be harvested within a short period (5-10 years), making it an attractive option for small-scale farmers looking for quick returns. The species' rapid growth allows for early returns on investment, which is crucial for small-scale farmers looking for quick financial gains (Zhang & Wang, 2021). Many farmers in Bangladesh prefer eucalyptus for its economic value and resilience in various soil types, particularly in rural areas with fewer alternative income sources (Bari et al., 2024). In Bangladesh, eucalyptus plantations have shown significant carbon accumulation, which can be monetized through carbon credits, enhancing the economic viability of these plantations (Azad et al., 2021).

Eucalyptus oil, extracted from the leaves, is celebrated for its therapeutic properties. It serves as an effective remedy for respiratory ailments, offering antibacterial and anti-inflammatory benefits (Wang et al., 2023). The oil's anti-inflammatory effects are enhanced when combined with synthetic drugs like flurbiprofen, reducing the need for higher doses of synthetic medications and minimizing side effects. The oil is a key ingredient in over-the-counter balms and inhalants, underscoring its importance in traditional and modern medicine (Sajid et al., 2023). Traditional medicine practitioners in many countries, including Bangladesh, recognize its effectiveness in treating colds and other respiratory conditions.

Eucalyptus can play a role in reforestation and combating desertification. Its ability to thrive in poor soils makes it an effective choice for degraded land restoration. Eucalyptus plantations can significantly deplete soil fertility, with a high abandonment rate due to soil degradation observed in other regions like China (Sete & Dagnew., 2023). Additionally, eucalyptus plantations act as carbon sinks, absorbing significant amounts of carbon dioxide and contributing to climate change mitigation (Gupta et al., 2019). Proper management practices, such as crop rotation and intercropping, can mitigate some of the negative impacts on soil fertility and improve the sustainability of eucalyptus plantations. Despite ecological concerns, eucalyptus plantations contribute to global timber supply and carbon storage, aiding in climate change mitigation (Sete & Dagnew., 2023). However, this benefit must be carefully balanced with its water consumption needs, which can stress local water resources.

Eucalyptus plantations are associated with a reduction in biodiversity. The replacement of native forests with eucalyptus can lead to habitat loss for local flora and fauna, disrupting ecosystems (Sarker, 2020). In Ethiopia, intensive monoculture plantations have led to a transformation of cultural landscapes and a loss of biodiversity, necessitating ecological improvement programs (Zhang et al., 2023). The expansion of Eucalyptus plantations often occurs at the expense of fertile cultivated lands, as observed in Ethiopia, which can further exacerbate biodiversity loss by reducing available habitats for native species (Tesfaw et al., 2022). This issue has raised concerns among environmentalists and policymakers in Bangladesh, where native species are vital to maintaining ecosystem resilience. 

One of the most significant criticisms of eucalyptus is its high-water consumption. Eucalyptus species, such as E. globulus and E. nitens, have been studied for their water use efficiency and sustainability. These species can consume between 350 to 900 mm of water per hectare annually, depending on the genotype and environmental conditions (Gashaw et al., 2023). This concern is particularly relevant for regions like Bangladesh, where groundwater availability is critical for agriculture and household needs. Studies show that eucalyptus trees deplete groundwater resources, posing challenges in water-scarce regions. The water use of eucalyptus is influenced by soil depth, with deeper soils leading to overestimation of water use efficiency, which can complicate assessments of their impact on water resources (Alain et al., 2022).

Eucalyptus leaves contain allelopathic compounds that can inhibit the growth of understory vegetation and disrupt soil nutrient cycling. Over time, these plantations can lead to reduced soil fertility and a decrease in native plant species, which negatively impacts biodiversity. Studies have shown that the buildup of eucalyptus leaf litter alters soil pH and microbial communities, making it less suitable for other plant species (Saif et al., 2023). The continuous accumulation of these compounds can lead to a decline in soil productivity, as seen in various studies where soil fertility and enzyme activity were negatively impacted by the presence of eucalyptus (Jian et al., 2023).

Eucalyptus trees are highly flammable due to the oil in their leaves. Climate change is increasing the frequency and severity of wildfires, as seen in various ecosystems, including eucalyptus forests (Michaela et al., 2023). In regions like southeast Australia, climate variability and long-term trends have led to unprecedented fire conditions, highlighting the need for improved fire management strategies (Hamish et al., 2022).

Eucalyptus cultivation in Bangladesh offers significant  economic benefits, particularly for farmers seeking low-maintenance and profitable options. However, the ecological implications of eucalyptus plantations necessitate careful regulation to prevent long-term environmental harm. Researchers and forestry experts advocate for sustainable practices, such as mixed-species plantations, to mitigate adverse effects on soil and water resources. This approach aims to balance economic gains with ecological sustainability. In Bangladesh, the decline in biodiversity due to the preference for exotic species like eucalyptus over native species is a significant concern (Alain et al., 2022).

To harness the benefits of eucalyptus while mitigating its adverse effects, sustainable practices are essential. These include:

1. Diversified Plantations: Integrating eucalyptus with Neem, Sal or others tree species can help maintain soil fertility and promote biodiversity.

2. Controlled Planting: Limiting eucalyptus plantations to areas with adequate water resources and avoiding ecologically sensitive zones.

3. Leaf Litter Management: Regular removal or composting of eucalyptus leaf litter can help balance soil pH and reduce allelopathic effects.

4. Regular Monitoring: Assessing the ecological and hydrological impact of plantations to ensure long-term sustainability.

The figure below illustrates the effectiveness of various sustainable practices for eucalyptus cultivation, including diversified plantations, controlled planting, leaf litter management, and regular monitoring.

This balanced perspective invites further discourse on the eucalyptus plant's role in sustainable development. By integrating evidence-based practices and ecological awareness, eucalyptus cultivation can be transformed into an asset for both economies and the environment.

Eucalyptus offers significant economic and medicinal benefits, making it a valuable resource for communities. However, its environmental impact, particularly in water-stressed regions, requires careful management. Bangladesh's experience with eucalyptus underscores the need for balanced forestry practices that align economic goals with ecological sustainability. By implementing mixed-species plantations and regulating plantation areas, the benefits of eucalyptus can be harnessed responsibly, supporting both livelihoods and environmental health.