Approximately two-thirds of India’s population of 833 million people resides in rural areas, with one-fourth of that population living below the poverty line. These individuals are forced to endure inadequate infrastructure, as well as poor access to services, resources, and markets. Rural connectivity during emergencies remains an important infrastructure need, which is particularly relevant for Northeast India, one of the most remote, underdeveloped, and ecologically sensitive areas of the country. Inhabited by Indigenous tribal communities and characterized by dense tropical forests, distinct orography, and heavy monsoon rains that often lead to flash floods and landslides, this region is at a threshold of transformation with the nexus between poverty, population explosion, and environmental degradation emerging as a critical threat. Community-based grassroots practices are being severely challenged and replaced with inappropriate solutions. One such threatened community-based and sustainable infrastructure practice is the Ficus-based living root bridge technology, pioneered by and unique to the Indigenous Khasi and Jaintia tribes of Meghalaya.1
Living Root Bridges
Locally known as jing kieng jri, living root bridges are cultivated from Ficus elastica in the dense subtropical moist broadleaf forest ecoregion of Meghalaya in the Northeastern Indian Himalayas. Ranging in span from 15 to 250 feet, these bridges are grown by the Khasi and Jaintia tribes over a period of 15 to 30 years and last for several centuries, demonstrating their exceptional endurance and resilience. With low cost, high robustness, remedial impact on the surrounding environment, keystone performance in local ecology, and support for other flora and fauna, Ficus-based living root bridge technology offers an exemplary model for sustainable infrastructure solutions and warrants further study in order to inform future living plant-based constructions.2
Study of the bridge growth process reveals the use of native, plant-based materials, handmade tools, and community expertise shared across multiple generations. This human–plant interaction instills a deep connection with the environment and reinforces a sense of interdependence. However, despite their many positive attributes, living root bridges are being gradually replaced with inappropriate solutions, such as steel suspension bridges and reinforced cement concrete bridges, which have an adverse effect on the fragile tropical ecosystems. Efforts to reverse this trend involve revitalizing plant-based knowledge through a socioscientific-entrepreneurial framework. Successful project implementation will ensure biodiversity protection, riverbank protection, soil quality improvement, and livelihood opportunities for the communities involved. This will gradually align Ficus ecology with socio-economic development, and ensure long-term socio-ecological resilience creating an exemplar for other tropical and subtropical regions around the world.
Understanding the underlying growth process of living root bridges is critical for improving its overall performance and value.3 The horticultural technique involves a four-stage process that can span up to three decades. This process includes the following: a) appropriate site selection and nurturing of Ficus plants on riverbanks; b) developing a temporary bamboo bridge and an Areca catechu root guidance system for nurturing and directing the young Ficus aerial roots;4 c) recurrent inosculation of aerial root fibers to create an integrated, seamless root network; and, d) successive addition of heavy stones, timber, leaves, and soil to plug gaps and improve the strength of the bridge. During this process, the bamboo scaffold is inspected annually to monitor its deterioration in wet conditions and repaired to address the increasing diameter of the Ficus roots. With time and use, the bridge develops exemplary strength and resilience, withstanding turbulent weather and eventually transforming into a living ecosystem for a range of flora and fauna.5
Rural Connectivity Project
As part of a statewide rural connectivity, conservation, livelihood, and learning project in Meghalaya that will be undertaken, four concurrent initiatives will be established to inform and advance each part. The rural connectivity initiative will focus on appropriate plantation and propagation of Ficus elastica along rivers and streams. This will be carried out in collaboration with local communities, with priority given to inaccessible, poverty-stricken, and vulnerable regions that are prone to flash floods, storm surges, and high soil erosion. These plantations will be nurtured over an extended time period to perform as robust bridges, creating a network of Ficus-based infrastructure solutions throughout the state.
The conservation initiative will focus on preservation and protection of these bridges through a precise ethnobotanical study of all the living root bridges in the state. The study will reveal the current state of these bridges and their relationship with the local communities, eventually creating a reference for subsequent research, development, and livelihood promotion.
The livelihood promotion initiative will create a green design cooperative that offers ‘living plant’-based development solutions that combine Indigenous plant knowledge with advances in contemporary science. These solutions can then be applied to other tropical and subtropical regions. Adapting the living root bridge as a biome for growing orchids, food, medicinal, and aromatic plants could increase the value of this horticultural technology for local communities and align local nutritional needs with Ficus ecology. Potential local food-based products that can be integrated with these bridges include honey, pepper, ginger, areca nut, cashew, strawberry, mushroom, and mandarin. Growth of medicinal and aromatic plants can create a platform for nature-based trade with potential markets in herbal medicine, cosmetics, and perfumes. Other possible interventions include redesigning the bridge to support non-powered vehicles and adaptation of the Ficus aerial root inosculation process for creating plant-based furniture, lamps, and woven sculptural artifacts.
The learning initiative will connect Indigenous communities with the scientific and academic community to study the growth, performance, and critical thresholds of the living root bridge technology. Focus will be on understanding the aerial roots of Ficus elastica and their relationship with the environment. Sharing the findings through a common platform will ensure community-based learning and feedback from all stakeholders. Key areas for scientific improvement include expediting the bridge growth process and ensuring structural safety during initial growth stages.3 Specific areas for experimentation include testing this horticultural technique for different inosculation methods and applying it to other tropical plant species, such as Ficus benghalensis, which could contribute to the application of this solution to a wider global region. The overall objective of the rural connectivity project is to demonstrate the potential of this horticultural technology and apply traditional knowledge for addressing contemporary challenges.
A research, demonstration, and experimentation field station has been proposed to initiate the rural connectivity project in Meghalaya. This station will serve as an essential link between all stakeholders and will provide continuous opportunities for collaboration and inclusion. Indigenous communities will work in close partnership with members from the conservation, entrepreneurial, scientific, and government communities to understand, improve, and replicate the living root bridge technology throughout the state. Various local, national, and international groups are currently being engaged to discuss and consolidate this project.
Living root bridge technology has extraordinary attributes, and its potential application for meeting rural connectivity can be achieved through a convergent vision. Combining conservation, research, and grassroots entrepreneurship can offer authentic solutions for revitalizing traditional knowledge and integrating it with contemporary needs.
- Ficus Missouri Botanical Garden [online]. http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/plant-finder/plant-details/kc/b597/ficus-elastica.aspx.
- Keystone species. National Geographic Society [online] (2016). http://education.nationalgeographic.com/education/encyclopedia/keystone-species/?ar_a=1.
- Shankar, S. Living root bridges: state of knowledge, fundamental research and future application. International Association for Bridge and Structural Engineering Conference: Providing Solutions to Global Challenges [online] (2015). http://www.sanjeevshankar.com/pdf/Living-Root-Bridges-by-Sanjeev-Shankar-IABSE-Conference-Geneva.pdf.
- Areca catechu (betel nut palm). Agroforestry.org [online] (2006). http://agroforestry.org/images/pdfs/Areca-catechu-betel-nut.pdf.
- Shanahan, M., So, S, Compton, SG & Corlett, R. Fig-eating by vertebrate frugivores: a global review. Biological Review 76, 529–572 (2001).