Flowers of the broadleaved bottle tree (top); Italian cypress in front of Humayun's tomb

THE TREES OF DELHI: A FIELD GUIDE By Pradip Krishen, DK, Rs 799

Since I first moved to Delhi thirty years ago, I have admired and enjoyed the tree-lined avenues of Lutyens's Delhi and slowly learned the names and facts about a few of the trees. Whenever a visitor came to the city, I would take him for lunch to the Taj Mahal hotel's rooftop restaurant and explain the layout of the capital to him. I would always wonder at the sheer density of the biomass below us. But I never got beyond identifying a few species. It was as if I, along with many others, was waiting for this book.

The Trees of Delhi is a work of great passion and occasional humour ' two attributes one would not expect in a book of this kind. It has a strong taxonomic base, but the science does get in the way of the practical introduction to India's trees. Not only is Pradip Krishen's new book a useable field guide, but it also has two other fascinating sections. There is a very accessible essay on the historical geography of Delhi. I had no idea that Chandni Chowk was lined with neem and peepal trees until 1912. Nor had I any idea of how Lutyens's team of town planners and arboriculturists chose the species that line the roads of the capital. A committee chose 13 main species for their evergreen quality and these were mostly exotics.

Woven into the text is a plea to replant and replace dying trees with indigenous varieties that are better suited to the climate of India. Krishen has mastered a new skill as a tree taxonomist, but he has not forgotten his training as a historian. And it is his skills as a teacher and film director that bring together all this information in a very clear format, with concise information, excellent illustrations (most of the photographs are by him) and insights.

The core of the book is the incomparable 'Tree guide'. Krishen has studied guides to the trees of many countries of the world, from New York's Central Park to the trees of Britain and has culled the best to create a simple but definitive layout. By using almost 1,200 photographs, the 'Tree guide' manages to illustrate the leaves, flowers, fruits of over 250 species. The 'Where to see it' entries are Delhi-specific but most of the information is applicable to any part of India. Some of the pages in this section are works of photographic art; the pages on the 'Bael-like leaves', and the 'Gulmohur-like leaves' are of great beauty.

But it is the section entitled the 'Back of the book' that gave me the greatest pleasure. Here Krishen has fun sharing with the reader his knowledge on subjects as diverse as how India Rubber bounced back to American homes to debates on the origin of the name 'bistendu'. The publisher should commission Krishen to expand the 'Back of the book' into a new compilation of facts. That would be a worthy companion to this extraordinary book.

Anyone remotely interested in our natural wealth should keep a copy of The Trees of Delhi. I am about to buy a second copy to keep in the car ' at last I will have something useful to read while I am stuck in Delhi's traffic. A recent article in a national magazine pointed out the negative aspects of life in the capital. This book celebrates an aspect of Delhi that we take for granted but would sorely miss if the trees were to disappear. The book, however, is not limited to the flora of Delhi but will be an invaluable companion in travels throughout India. I am carrying a copy on a trip to the botanical gardens next week.