A peek into the State's biodiversity heritage site

Nallur, a village in Devanahalli taluk, Karnataka hosts India’s first biodiversity heritage site: a tamarind  grove. The grove traces its origin to the Chola period and was seen as a Devarakadu (sacred grove).

Located nearly 45 km from Bengaluru and nine kilometres from Devanahalli, the grove is situated on the Devanahalli-Hosakote Road. Spread over 53 acres, it currently has 295 gigantic Tamarind trees. In 2007, the grove was declared a ‘Biodiversity Heritage Site’ through a notification under the Biological Diversity Act, 2002 by the Government of Karnataka. Since then, it has been fenced and is under the care of the State Forest Department. 

In 2012, a documentation project by the University of Agricultural Sciences — headed by Dr R Nandini, associate professor in the Department of Genetics and Plant Breeding, and sponsored by the Karnataka Biodiversity Board — was undertaken. It documented the trees, determined their age through radioactive carbon dating techniques and carried out a study pertaining to the pattern of diversity within the tamarind population.

According to Dr Nandini, the majestic trees have survived the vagaries of time  and reveal propagation of shoots from mother trees into full-fledged trees, something uncharacteristic of tamarind trees. The surfaces of these trees are either smooth or rugged. Some of them have developed peg-like outgrowths which later got mounted with tumour like structure piled one over the other. In some cases, even shoots from a single mother tree have developed into clones or independent trees bearing the same genetic characters.

Sanctity of the grove and several mythical accounts associated with it prevent the locals from plucking the fruits that  have an unusually rich pulp content. The yield is now auctioned once every year by the Forest Department. Though there is little by way of evidence to testify the veracity of them, the historical narratives lend a queer aura to the place. Two temples located here add to the grove’s antiquity.

Regional variety

The grove could easily be considered a gene pool of tamarind trees typical to the region. Some of the trees are aged
between 100 to 200 years while the youngest of the trees is 84 years old. Nandini says the diversity could be imagined from five different crown shapes, four different foliage types, three different flowering and trunk styles. Trunks interwoven in complex wedge styles display interesting patterns. Most trunks have, however, hollowed out with complete erosion of
cortex.
Tamarind derives its name from how it was described by the Arab travellers. They called it ‘Tamur al Hind’ (the Indian dates) which got transformed into Tamarindus indicus by the famous Swedish taxonomist, Carl Linnaeus in 1753. Since the locals do not extract the fruits or harm the grove in any manner, the grove has developed all the features of a natural forest. Several trunks have developed huge calluses. One such callus, which in fact is a bunch of rounded ends of branches, stands several feet tall. Interestingly, a clone tree has sprung out from its side. Yet another huge tree cracked into two parts due to a lightning around 80 years ago. Both the parts have developed into two independent trees leaving out passage wide enough to allow even a bullock cart to pass.
Dr Nandini collected samples of the wood from the core of 18 different trees for two institutes — Birbal Sahney Institute of Paleo-botany, Lucknow and Institute of Physics in Bhubaneswar. Two different techniques were applied to determine the age of the trees. The carbon dating tests conducted confirmed that the oldest tree in the grove is 410 years old, while several others are aged around 200 years.
Unique features
It is the antiquity of the trees and heterogeneity of their structure that confers uniqueness as well as heritage value on the grove. These very features propelled the Karnataka Biodiversity Board to take notice of the extant biological wealth and sponsor the project. The grove could also serve as a veritable tamarind gene bank. The longevity of these trees will be as much a subject for research as their productivity and uncharacteristic growth of props which were so far known to be a feature of Great Indian Banyan trees.  
In another study, Dr Nandini has suggested that superior trees from the grove could be selected for clonal propagation as tamarind is an economically important tree. These trees could be identified on the basis of higher pulp weight to seed weight ratio. Her research has even identified such trees from the cluster for monoculture plantation.
Nallur Tamarind Grove is an interesting laboratory for research on tamarind trees and constitutes an invaluable archives of the trees where myths, faith, medieval botanical wisdom and popular preservation techniques have gelled together to give rise to a biodiversity heritage site.