Fire and forest

One day in Manas National Park I took the photo of forestry men on foot. The smoke behind them tells you that they were going about their summer job (white hot March is summer in Assam, just before the onset of the monsoon) of setting controlled fires to manage the grassland habitat. Forest and fire. The two words don’t seem to go together, but that is the legacy of English: both the language and the empire. When the English came to India and saw these ancient grasslands, they didn’t have the language to understand them. They hadn’t yet seen the grasslands of South America or Africa. In North America the destruction of grasslands had begun (think Johnny Appleseed). The English invented the phrase “degraded forest” to describe these grasslands.

To understand the fallacy in this, I reached a little further back into history. Grasses evolved about 75 million years ago in ancient Gondwanaland, before the dinosaurs dwindled due to a series of volcanic eruptions that tore that super-continent apart into the Americas, Africa, India, and Australia (that an asteroid impact killed the dinosaurs after this is another story). How did this evolutionary marvel spread across the world? One theory is that geasslands spread across northern Gondwanaland (present day South America, Africa, Asia, and India) before its breakup. This theory runs into problems with the evolutionary clock. In order for this early spread to have hppened, many families of grasses would have had to evolve earlier than they are known to have. The second theory is that the evolution of grasses happened in the isolated island-continent of India before it met Asia, and the grasslands spread from there outwards to the rest of the world after the contact. This theory has to contend with major geological barriers to its spread. Perhaps neither theory is right, but nevertheless, India is home to some of the oldest grasslands in the world, and also to some of the most ancient grazing animals in the world (Bharattherium bonapartei is one of them). In order to begin preserving this heritage, we have to give up notions encapsulated in phrases like “degraded forests”, “dry scrubland”, and “wasteland”. The lack of trees is not lack of biodiversity. The rich grasslands of Assam are evidence of it. Look at the bottom of the photo above: the number of varieties of grasses and herbs you see is more than that of the trees above them.

There are other aspects of grasslands which should concern us in this era of a changing climate. Grasses evolved new pathways of photosynthesis to deal with hot and wet weather: the technical name is C₄ photosynthesis. In contrast, the grasslands of the Himalayas have many species which use the older C₃ photosynthesis. In the ancient battle between forest and grassland, our inadvertent tuning of the atmosphere has shifted the balance. Grasslands are also prone to fire, and trees and grasses which grow in them have evolved to use it. Often seeds lie dormant until the heat of a fire starts new growth. When the ancestors of humans responded to an ancient climate crisis, 2.5 million years ago, by adapting from arboreal to grassland life, they would have encountered fires very often. The use of fire distinguishes Homo habilis and its descendants, us, from all our remaining cousin species of apes. The forestry men I saw were using an old human technology to maintain the environment that gave us this technology.

The language I use to deal with the wild spaces around me is wrong. The culture surrounding it is wrong. Still, that’s what I’ve grown up with. I cannot name the grasses that I see. But I can name the flowering trees. I recognized the beautiful purple flowers of Bauhinia variegata as soon as I saw them. The orchid tree, as it is sometimes called, grows from sea level, here, up to the lower heights in the Himalayas, and eastwards across South-East Asia and Southern China. It was one of the several flowering trees that I recognized in Manas.