Adding to the article based on ‘Trees of Chennai’ by Prof. K.N.Rao (Madras Musings, December 1st issue), here is further information on a few popular trees of Chennai as well as of India.

Neem (Azardicta indica)

Its bitter principles were once making headlines as a possible cure for AIDS. India has an estimated 14 million trees, yielding 450,000 tonnes of seeds with 20% neem oil. Neem-based insecticides have toxicological effects on over 300 types of insects. Its oil is said to be effective in the treatment of leprosy and skin diseases, and its leaves are used for treatment of wounds. After extraction of the bitter fraction, the oil is also used in making soap. Azadiractin, a chemical constituent, has insect-repellent properties. The main component of the oil is nimbidin which is very bitter and is used for making several pharmaceutical products. In Tamil Nadu and other States in India, forest departments grow neem on a plantation scale.

Coral tree (Erithrina)

The Coral tree, commonly seen in all parts of Chennai with its lovely red flowers, is quite an experience. There are six species of Erithrina popular in India. The spiny variety is used as a standard for growing pepper, and the smooth barked variety used to be grown as shade trees in tea plantations. The seeds are never consumed by birds or animals. They contain hypophorine, a tetanising alkaloid, a very rare toxic chemical, that is more poisonous. The Mexican variety has a powerful chemical yielding that even paralyses the motor system. The extract is a substitute for curare, used to poison the tips of arrows of South American Indian tribes.

Coral trees, or dadaps as they are called in the planting districts, are gross feeders.

We had one of them 20-25 feet away from our flats’ concrete water tank which had a concrete cover. In about five years, its roots cracked the tank’s sides. When we started the repair work, we collected some 20 kg of invasive roots from inside the tank. After the repairs, I wanted our Association to fell the tree so that the problem will not repeat. Tree sympathisers stopped us from doing that. Four years later, it became a giant tree and this time it cracked the concrete cover of the tank besides the sides, causing bigger damage. More than 100 kg of its roots were found inside the tank. The Association spent Rs. 25,000 to repair the tank and those who had objected to the removal of the tree now agreed to the felling of the tree, which yielded more than a truck load of wood. So this is not an eco-friendly tree for animals or human beings. Chennai should think of making a list of non-eco-friendly trees. Another such tree is the Indian Skunk tree, Sterculai foetide, also called the hill coconut. Its pods when dry offen fall on people’s heads and the tree should not be grown near flats where cars are parked or even as avenue trees.

Tamarind
(Tamarindus indica)

The tamarind is a very useful and popular avenue tree. Its unripe fruit is a rich source of tartaric acid which is used extensively in various foods, chemical and pharmaceutical industries and in Indian medicines. The pulp is also used in dyeing and tanning, and to polish and clean metalware and utensils. The timber is used to make agricultural implements and furniture.

It was recently reported that cleft grafting of tamarind brought the tree to yield in four years instead of as long as twenty years.

Mast tree (Asoka tree) (Polielthia longifolia)

Mast (Asoka) tree.

A lovely tree, it belongs to the Anonaceae family which includes the custard apple (sitaphal). It derives its name from its very straight and tall high quality main mint that is used as a mast for ships. It is a misnomer to call it the Asoka tree. Another species, P. fragrana is grown to make billiards cues and cricket stumps. Its bark is used to treat scorpion bites. P. longifolia is a very attractive avenue tree and when planted closely in double rows the trees can make a tall green screen. This can reduce noise levels affecting residences close to main roads and also reduce pollution levels.

These trees host lac insects in North India.

There are six species of Annona in India. The powdered leaves and seeds of A. squamosa (Sitaphal) possess insecticidal properties. Similarly, the seed oil of A.reticulata, (Ramphal), grown in Northeast India and South India, is used as an insecticide.

Mahogany tree
(Swietinea mahagoni)

There is a lovely avenue of these trees in the Theosophical Society, Adyar. During the golden jubilee of the Society in 1925, each tree was labelled with the name of each member country of the Society and sand from the respective countries was symbolically strewn around the tree by the delegate from the country associated with it. There is also one tree in the Chennai Museum campus, much taller and bigger and older, looking great in shape. The wood is very good for making furniture.

Mango (Mangefera indica)

India has 10.7 million hectare under mango cultivation with Andhra Pradesh having 19.27 per cent of it, West Bengal having 22.31 per cent and Tamil Nadu 5.18 per cent. The productivity is 12, 8 and 6 tons/hectare respectively, with India’s average at 8.12.tons/hectare. I have seen wild Mango in the Western Ghat forests. Its fruit is just a seed covered with skin.

There is one huge mango tree near Chandigarh which seems to hold the world record. The tree has a trunk with a girth of 32 feet and branches up to 80 feet long and 12 feet in circumference. It covers an area of 2700 square yards and yields 37,000 lbs (16,760 kg), possibly a world record for any given fruit tree!

There are over 1000 varieties of Mango, but grafting them gives the standard varieties in various regions of India and the world.

Almost all Indian varieties of mango are mono-embryonic. Seedlings raised from them are not true to the mother tree and need to be grafted to the scion of suitable variety.

(To be concluded)