Plant Grass Instead |
Listen to this article:
A tall, majestic tree silhouetted against a blue sky. The cool shade of a tree on a hot sunny day. A tree with branches laden with juicy fruit. The magical tree-house of childhood. Trees have dominated our imaginations, as encapsulated by Joyce Kilmer in his ode to trees, “I think I shall never see, a poem lovely as a tree.”
Yet it wasn’t in the trees, but in the open grassy plains and savannas of Africa that our bi-pedal ancestors evolved, that taught our species to stand tall and look to the horizon, that allowed Homo sapiens to travel across earth and become its most dominant species. Somehow, that grass beneath our feet, far from our uplifted gaze, has not enjoyed the same place in our collective imagination.
A history of being undervalued and misunderstood
Historically and in the current day, our collective fascination with trees and forests, and by corollary, our neglect of open grassy biomes has had very real consequences for how we have come to understand, value and conserve the natural ecosystems around us.
Globally, as the extinction crisis of the past century has unfolded, scientific research and conservation funding have been overwhelmingly focused on tropical rainforest diversity and the crisis of tropical deforestation. So much have these majestic forested ecosystems dominated our imagination that a formal term has been adopted for it, Biome Awareness Disparity (BAD). BAD captures the idea that forested biomes have garnered more than their fair share of attention, even as other, equally ancient biomes with their distinctive biodiversity, and in the case of grasslands and savannas, unique and vibrant pastoral cultures, have been in plain sight. Indeed, the rate of loss of open biomes both predates and outpaces rates of tropical deforestation over the past century, but undervalued and perceived as “less than pristine”, “degraded” systems, these losses have not garnered concern until very recently.
In India, as in many other parts of the tropics, these perceptions are historically entwined with the advent of the colonial enterprise. Here in the subcontinent, the modern classification of vegetation was formalised at the start of the colonial era. Colonial foresters, trained in forestry traditions from densely forested, cooler climes, were charged with surveying the colonial lands, with a special eye on timber, an important revenue source for the colonial state. In this tree-centric lens, all ecosystems with some trees in them came to be classified as a type of “forest”. Thus, while the densely wooded formations of mesic regions such as the central India or the southern peninsula came to be classified as dry deciduous forests, the sparsely-treed formations of the semi-arid regions of the Deccan and interior peninsula were classified as thorn or scrub forests. But the visible presence of humans grazing their livestock herds across these landscapes and setting dry-season fires to encourage fresh grass growth for their livestock in the monsoon the followed, lent itself easily to the perception that these were human-modified, degraded systems which in the absence of humans, would have been closed forests. The more open and degraded of these regions, seen as unproductive in terms of resource extraction, came to be administratively classified as “wastelands”. Further west towards the desert, where there were vast grassy landscapes, it was clear that the region was too arid to support trees, but these open landscapes, seasonally home to migrant pastoralists and their herds, were also easily labelled as “wastelands”. This world view truly missed the grasses for the absent trees. It failed to recognise that the productivity of these ecosystems lay in the abundant grazing animals and livestock supported by the grass, and that the livestock products they generated were the heart of a thriving economy based on adaptive and mobile pastoralism.
The legacies of these misperceptions continue to impact vast areas of India’s open natural ecosystems today. While open natural ecosystems occur on about 10% of the land, a mere 5% are protected, typically small areas set-asides for endangered specialists of the open habitats such as the great Indian bustard and the blackbuck. A troubling 69% of them are classified as “wasteland”, a category still used by the Indian government’s administration. Over time, these have steadily been diverted to “more productive” land-uses: industry, agriculture, built-up settlements and development projects, transforming them into completely anthropogenic landscapes. Gradually, quietly, these transformations have displaced the pastoral people and their livestock, who seasonally migrated across these lands for centuries, and who are now constrained into ever-shrinking remnant fragments of natural grazing pastures.
Ironically, in recent years, these open lands are targets for conversion to green energy projects and tree-planting for climate mitigation. In the latter context, India has made a national commitment to bringing 26 million hectares of land under green cover, which generally means tree cover, by 2030. These commitments have resulted in accelerated tree-planting drives across the country, much of it in our arid and semi-arid grasslands and savannas.
Not an optimal climate mitigation solution
A growing body of recent research establishes that tree planting in arid and semi-arid lands, in open natural ecosystems like grasslands and savannas that have intrinsically low tree cover, often does not bring the carbon and climate benefits intended. Planted trees often don’t establish well, exhibiting poor growth and high mortality. The digging of trenches for planting seedlings results in large pulses of carbon loss from the perturbed soil. Thirsty trees extract much more water from the ground than grasses, compromising hydrological security. The lower albedo of dark green trees relative to the light green grass results in greater localised heat absorption and warming, with compounding effects on water and nutrient cycles. Where tree plantations, typically of a few fast-growing species, do establish, they show losses of native biodiversity, of the plants and animals that were specialised and adapted to the seasonally dry, water-limited, hot and open environments in which they evolved. Tree-plantations, often fenced, take away grazing land from pastoralists, who have long depended on these communal grazing pastures for maintaining their livestock. Even where they are not fenced, grasses get shaded out beneath the trees, reducing fodder availability. As the economics and funding machinery of tree-planting for climate mitigation gain momentum, the remaining grasslands and savannas of India, their unique biodiversity, and the pastoral cultures and livelihoods they have supported for centuries are significantly at risk. All of this without any guarantees that the planted trees will bring the anticipated carbon gains.
So, where and how should trees be planted?
When it comes to tree planting in natural habitats, whether it is for restoration or carbon sequestration, a general rule of thumb should be: The right species of trees, in the right habitats, and at the right densities.
Scaling up this rule of thumb, at the national level, tree planting programmes should follow principles that will enable carbon mitigation through tree planting, but minimise harm to the open natural ecosystems in the country that are already severely diminished. Towards this, a calibrated approach to tree planting should prioritise the following:
Restoration of degraded forests,
Planting in urban, semi-urban areas, industrial estates and farmland edges,
Reclamation of mined lands in previously forested landscapes, and
Where not compromising of food-security and social justice, promotion of some mixed agroforestry in agricultural lands.
So, where should trees not be planted?
Tree-planting should ideally be avoided in arid and semi-arid ecosystems, that is, grasslands and sparsely-treed savannas.
That is the ideal, but where the wheels of economics, planting programs and financial mechanisms to promote them are already underway in semi-arid and arid open natural ecosystems, we urgently need to flip the narrative. We need to change the focus from aboveground carbon in trees to below-ground carbon in soil.
In open natural ecosystems, instead of planting trees, plant grasses. This simple change in strategy will allow the financial mechanisms that have been committed to climate mitigation to continue, will contribute to carbon sequestration through soil carbon, and will continue to bring the anticipated livelihood benefits to local communities through the establishment of grass nurseries and grass planting. All of this while avoiding the negative ecological consequences and economic losses associated with tree planting in the wrong habitats.
In time, if such grassy areas and pastures are restored at scale, they will also contribute to better livestock production, which is suffering from degradation of pastures as land available for grazing has shrunk due to being diverted to other land uses. While the terms of grazing regimes in restored landscapes will have to be negotiated, done with care, this will not only support excellent soil carbon outcomes, it will also improve the outlook for migrant pastoralist economies that have long been amongst the most sustainable and green livelihoods in arid and semi-arid regions.
Natural ecosystems are complex, our efforts to restore them and slow climate change must reflect that same nuance.
When it comes to ecosystem restoration for climate mitigation, we need to embrace a diversity of approaches that reflect the nuances of complex natural systems. It should come as no surprise to us that even as mesic and wet tropical forests are great at sequestering carbon aboveground in the trees, arid and semi-arid grasslands and savannas are much more efficient at storing carbon belowground in their roots and in the soil, where, as a bonus, it is safe from droughts and fires that are common in these habitats. At scale then, we must adapt our nature-based climate mitigation solutions to match the natural ecology of the ecosystems in which they are taking place.
One size does not fit all
Taking the time to internalise the above, and tailoring our efforts to match this complexity will yield far greater returns than any seemingly-simple, sliver-bullet solutions.
But above all, it is critical that we be clear-eyed to the fact that no amount of tree-planting, grass-planting or other forms of nature-based climate mitigation can compensate for the amount of carbon that we humans have added, and continue to add, to earth’s atmosphere through our fossil-fuel driven economies. Ultimately, any real solution will require us to de-carbonise our lifestyles and economies at planetary scale.
Jayashree Ratnam is at the National Centre for Biological Sciences, Tata Institute of Fundamental Research where she serves as Program Director of the Wildlife Biology and Conservation Program. She is a community and ecosystems ecologist who works across the tropics.
This is the eighth article in a series exploring the challenges faced by Indian pastoralists. Read the first, second, third, fourth, fifth, sixth and seventh.