Prosopis juliflora: An Agroforestry Horror Story
Gather around, I will tell you a story of an agroforestry project in Tamil Nadu. Of course, no one may have known or predicted the terrible destiny of this particular agroforestry project. However, it is important that we understand and learn valuable lessons from this well-intentioned experiment gone horribly wrong. It is especially critical at this point in time when tree planting, agroforestry, social forestry, Miyawaki tiny forests, conservation agriculture, et al., are becoming popular once again.
In India, this water guzzling invasive alien harms entire ecosystems — posing threat to birds, degrading biodiversity in tiger reserve forests, increasing malaria transmission, and more. Apparently, Seemai Karuvelam tree is an invasive menace only in introduced regions, but not in its native habitats.
The Past: Seemai Karuvelam Trees — a Miracle Cure
Many decades ago, facing a severe drought and shortage of firewood, the then government of Tamil Nadu promoted Seemai Karuvelam (சீமைக் கருவேலம் / Prosopis juliflora) among small farmers. [An abbreviated timeline: Colonial Indian government introduced the species around 1870. Tamil Nadu government promoted the species across the state in the 1950s, after independence.] Fast growing tree, high drought tolerance, provides plentiful firewood, creates new livelihood options — what is not to like? Many multilateral and international development organizations hyped the species. For example, here is UN’s Food & Agriculture Organization (FAO) and UK’s international development agency DFID manual on Managing Prosopis juliflora (pdf), extolling the virtues of this miracle tree and suggesting plantation forestry. Quoting from the manual with the contrasting view from the experts and local populations:
Since colonial times, planners, policy makers, and forestry experts have given much emphasis to introducing fast growing and well adapted exotic wood species from iso-climatic regions of the world into arid and semi-arid India. Some of these exhibited remarkable adaptability and growth in their new habitats. Prosopis juliflora (Swartz) DC is one of those species that has performed much better than many native woody species. …
With its tremendous ability to adapt to arid and semi-arid environments, and its fast growth and multiple utility, it has long been recognized by foresters as a versatile species for afforestation. However, rural people in arid and semi-arid regions of India are a little apprehensive of this species as (i) they consider that the species adversely affects crop growth and production; (ii) there is a fear that it may become a weed; and (iii) the thorny stems and branches of the species often cause injury to humans and animals, and hinder agricultural operations.
The Present: Seemai Karuvelam Trees — an Invasive Nightmare
Fast forward to current times. Scientific journals are confirming that rural people’s ‘apprehensions’ were well-founded after all. With decades of adaptability under its belt, the tree has morphed into an indestructible super-villain. Seemai Karuvelam tree is a “noxious invader in Ethiopia, Hawaii, Sri Lanka, Jamaica, Kenya, the Middle East, India, Nigeria, Sudan, Somalia, Senegal and Southern Africa.” In India, this water guzzling invasive alien harms entire ecosystems — posing threat to birds, degrading biodiversity in tiger reserve forests, increasing malaria transmission, and more. Apparently, this tree is an invasive menace only in introduced regions, but not in its native habitats.
It is not as if India didn’t have another tree like this. A similar species that co-evolved natively in India has less toxic effects on biodiversity. The research study on Community Impacts of Prosopis juliflora Invasion: Biogeographic and Congeneric Comparisons finds that “Prosopis cineraria, a native to India, had much weaker effects on species richness in India than P. juliflora.” (nature and evolution seem marvelous doesn’t it?).
A public interest litigation filed in Tamil Nadu in 2015 resulted in a court order for all district administrations to take steps to eradicate the tree. Details can be found in Why TN government is uprooting thousands of trees to prevent water-bodies from drying up. However, it is not that easy. Seemai Karuvelam tree is virtually indestructible that experts are recommending that we “manage” the invasive alien tree rather than try to eradicate it altogether. See a few examples in Prosopis … management of one of the world’s worst woody invasive plant taxa and To eradicate or not to eradicate? … Prosopis juliflora management in Afar, Ethiopia.
For, Seemai Karuvelam, invasive that it may be, has become a native alien by now, with its own ecosystem that requires a careful and caring transition over to a new ecological regime.
Eradicating Seemai Karuvelam is not an exclusively biological problem either. There is now a social barrier to removal, thanks to the perverse incentives built into that agroforestry experiment. Remember that ‘livelihoods’ angle from when the species was introduced? Seemai Karuvelam has become a key part of charcoal energy industry. It is now providing livelihoods for farmers with uncultivated land. A study in 2012 found that there is considerable earnings from converting wood into charcoal, especially for a small farmer:
The direct selling of fresh wood from 3–5 year old tree stands provide 16,500/acre and 5–10 year old tree stands provide 24,750/acre. The gross income of charcoal production from first quality wood was 38,250–42,500/acre and second quality wood was 33,750–37,500/acre. In the absence of any investment and maintenance, P. juliflora provides monetary support to the rural community.
Of course, charcoal briquettes have their own environmental issues. However, now the state of Tamil Nadu is stuck, caught between ecological disaster and livelihoods. Studies point to the humongous costs the invasive alien species cause to agriculture and forestry — about $91 billion per year! And yet, even environmentalists are divided on undertaking full eradication because of the impact it would have on livelihoods, especially among small farmers in the drier regions of Tamil Nadu. However, even if the social and economic problems are solved, eradication has to be carried out sensitively, causing in-fighting among environmentalists on the best course of action to take. For, Seemai Karuvelam, invasive that it may be, has become a native alien by now, with its own ecosystem that requires a careful and caring transition over to a new ecological regime.
What Next?
This is the past and present. What lessons can this teach us as we design new agroforestry programs? Instead of offering top-down, monocultural tree plantations as solutions, how might we learn from local communities and incorporate traditional wisdom into creating innovative, biodiverse agroforestry solutions for the future? How can we incentivize local communities, especially small farmers, into creating a thriving ecosystem?
We will reimagine agroforestry in part 2.
