Monday, May 10, 2010

#33. Acacia

Prsosopis juliflora......Vilaiti keekar

Acacia melanoxylon
Acacia mangium

Acacia tortilis

Acacia auriculiformis

Acacia Sengal

. Acacia catechu......... .Kattha,Khair

Acacia nilotica flower

Acacia nilotica in flower
(Picture credit Wikipedia, Blackwood image from the google search engine)

The Story of Babool

One hears about and sees babool all around in our country, but never know anything beyond the basic facts about the plant. I started my search on the net and some of the interesting facts I came to know for the first time. Acacia is a genus of trees and shrubs which has about 1300 species, about 960 native to Australia and the rest to the tropical and warm-temperate regions of Africa, South Asia and the Americas. In such a large group, obviously some would be good and useful to the human kind, and some of their cousins not so . A reputed quasi-religious organization of India has given a list of 3 no-no plants which are: Acacia, mangium and nilgiri. Mangium is Acacia mangium, an invasive but useful plant. Nilgiri is Eucalyptus, and it is admitted now openly or otherwise that its transpiration rate is high, and lowers the water level. But to condemn Acacia as a genus would not be fair. Some varieties are useful, and have been so for millenniums. Let us think about at least the prominent among them.
Acacia nilotica is our native babool. I am fond of it because it is the favourite of birds, as they find it safe for perching, roosting and nesting because of its large thorns. You can sometimes see a colony of baya nests hanging on it , and many a tree of this variety reverberate with the chirping of various birds like house sparrows, prinia, bulbul and other smaller birds. Its wood is used in villages for agricultural implements, and other minor furniture, and interior villages also use it for protecting trees from kettle during the first few years.
After delivery, the mother is given heavy protein in the form of sweets made of nuts, and dry fruits. Also included is laddoo made of gum and sugar which they say thickens the milk. Well, gum in the earlier days was collected from so many trees, but the best gum was obtained from Gum Arabic (Acacia Senegal). From the name it is clear that it is a native of Africa. It is found in West Africa from Senegal to Nigeria. Acacia arabica (a synonym of Acacia nilotica) tree is the gum Arabic of India, and gives gum of inferior quality. To add to the paradox, A.nilotica has become a species of serious concern in Australia as it is currently invasive in nature there.

What is Indian food without paan (betel leaf). Paan is laced with kattha and slaked lime. Betel nut, scented matter, and scented tobacco (for those who like it) are added to it to make it more tasty. Kattha is made from boiling the stem of Acacia catechu which generally grows wild in Indian forests and is jealously guarded by the forest officials. The tree is allowed to be cut only after it attains maturity.
Acacia melanoxylon (Blackwood) is a highly valued temperate acacia species. It is a native to Tasmania, South Africa and Chile. It can go upto 45 metres in height, and is used in construction and furniture making.
Acacia mearnsii (Black Wattle) is also an important temperate acacia.

Acacia modesta (Phulai) is a native of West Pakistan, Afghanistan and India (Punjab and U.P.). Wood is hard and durable, and is used in the villages for cane crushers, Persian wheels and other agricultural implements.

Acacia tortilis (Israeli babool) is the dominant tree of many Savannah communities. It grows wild in Sinai desert. Flowers are highly aromatic, and it can tolerate extreme arid condition. It is also known as Umbrella Thorn and is a staple browse for camels and goats. One tree gives 14 to 18 kgs of pods and leaves in the year. It is a Biblical tree, and it is believed that its wood was used for the Ark of the Tabernacle. This tree has been recommended for the reclamation of Rajasthan deserts, and I think it is an excellent idea.
Sweet acacia (A. farnesiana, Needle bush) is a weedy plant. Its roasted pods are used in sweet and sour dishes. Flowers are processed through distillation to produce a perfume called cassia. It is considered a serious weed in Fiji and parts of Australia.
Acacia planifrons (Umbrella thorn) is a native of southern part of India and Srilanka. Apart from its wood, there is not much to say about this specie.

Now we come to the more controversial species. The first is Acacia mangium. It can go up to 30 meters. It is a native of Australia (Queensland), Molluccan islands, Papua New Guinea and Indonesia. Large scale plantations have been developed in Indonesia and Malaysia. However, it is invasive in the sense that it replaces the local trees. In Tamilnadu the Forest department is cutting these trees. A. mangium is a fast growing species with numerous seeds and therefore it outperforms other trees. Each tree produces a kilogram of seed per year which is about 80,000 to 110,000 seeds. The result is that it stifles the growth of the native trees and disturbs the ecological balance. The tree has been found invasive in Sabah, Africa and Melville Island in Australia. The plus point of the specie is that it has rapid growth, and is tolerant of very poor soils. It can go upto 30 meters, 15m and 40 cm girth in 3 years and 23 metres in 9 years. Wood chips are used as paper pulp, and timber is used for building and furniture. A hybrid of A. mangium and A. auriculiformis has been found to be more vigorous and has better timber.
Leucaena leucocephala (Acacia palida), a native of Australia, was brought to India with much fanfare. It is an excellent proteinous fodder, and Indira Gandhi was so impressed with the plant that she said that it should not be called kuabaool' but subabool and the name stuck. It is a spindly tree and is easily spread by seeds grown in abundance. It spreads quickly in clumps in surrounding areas and it is difficult to get rid of.
Acacia auriculiformis (Earpod Wattle) is another variety which has recently been introduced in India. It is non-browsable and fast growing, and therefore liked by the Forest department. It is leguminous. It was used as an ornamental plant in Florida , but was found to have invaded pinelands, scrub and hammocks in South Florida, and thereby, displacing native vegetation and threatening to shade out rare plants. Its use as an ornamental plant has also been restricted because of the litter it produces. Overall, in spite of some good points, I do not think it is worth encouraging by the Forest as well as Horticulture departments.
A species which is often mistaken for acacia is Prosopis juliflora. This is a thorny shrub or small tree, native of Mexico, South America and the Caribbean. There was a time when for the reclamation of Chambal ravines near Gwalior in Madhya Pradesh its seed was sprayed by helicopter. The programme succeeded in the sense that it got established in the ravines but it also spread to the nearby areas. Soon it was found to be highly invasive in nature. It spreads on its own. Birds do not like the tree because it is so dense that it is unsuitable for roosting and nesting. In a study conducted in Kenya where it was imported, it was found to be not beneficial to the herders as it stifles the favoured grasses in spite of its being a source of livestock fodder in pods. It was found to be invasive into cropfields, grazing areas and wetlands which are useful for dry season grazing. Apart from the fuelwood use and fencing in a basic way, it was not found to have much use. On the whole, another useless plant.

The perception of the people about the invasive species is influenced by how they weigh their benefits against the harmful effects. The invasive plants have some good points but it is better to be cautious before introducing them to a new area. The invasive plants mentioned above have more minus points. The native varieties are always better. We have several instances of exotic plants brought to India with much hope and hype, or for their beauty, and have been found to have more harmful effects. Water hyacinth, lantana, ipomoea, parthenium, eucalyptus are all exotic, and they have had negative influence on our ecological balance. On the other hand, potato, tomato, cauliflower, green chillies, tobacco and sorghum are all exotic plants. So are apple and grapes (from the olden times).

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