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.

Orchid trees

Our trip had been planned badly, so we spent really long hours on the road. There was little time for long walks, and in any case the pervasive smoke from forest fires made it impossible most of the time. As a result, the opportunity for bird watching was limited, and I decided to concentrate on something I’ve long put on the backburner: identifying trees. On the day-long drive from Almora to Munsiyari, I spotted a tree full of white flowers by the road, and stopped. A closer look told me that this was Bauhinia variegata.

The characteristic shape of the leaves of the genus Bauhinia has been called “camels’ hoofprints” by Pradip Krishen in his field guide Trees of Delhi. Less poetically, when you flatten out a leaf, it seems to have two lobes. The five-petalled flower has colours which can range from purple to white, hence the specific name variegata. You can find this tree across India up to an altitude of about 1500 m. As a result it has many names in different Indian languages. I think I’ll stick to the Kumaoni name, Kachnar for now, instead of the fancy English constructs like mountain ebony or orchid tree. After all, Corbett just calls it Bauhinia. In Kumaon I saw the flowers used in food, and read later that the flower as well as leaves are eaten in various parts of India. Apparently its uses in medicine have been documented for a long time. The full geographical range includes Pakistan, India, Myanmar, and southern China. It would be interesting to check whether it is used for cooking in Cantonese food, or, more accurately, in the kitchens of Guangdong.

In most of the flowers that I saw, three of the five petals stand close to each other, sometimes overlapping, and two are quite separate. As a result, from many angles a photo shows all five petals, and all five long stamens. One petal is always multicoloured, making it a very interesting subject for photography. As I read more about this genus, I saw that it contains species across the world’s tropics. Is this then a very ancient genus? Apparently not. Fossil and molecular evidence agree in placing its origins in Eastern Asia only around 60 million years ago, just about the time that India banged into Asia. So its dispersal across the world is not due to continental movement. Amazing that seeds and seedpods can travel such long distances!