In the lower plains of the forests in Arunachal Pradesh, there is a species of trees that produce a fruit called the Elephant Apple (Dillenia indica). It is larger than a cricket ball in size and – as the name suggests – a very popular fruit with the elephants, who enjoy gorging on the sour tasting, juicy and fleshy fruit. In return, these large mammals help the trees with seed dispersal.
Then there’s the False Hemp Tree (Tetrameles nudiflora), which towers over the forest canopy. This tree is a favourite among the native hornbills, barbets and woodpeckers, as its soft wood is ideal for the birds to carve out nests.
These and many more botanical gems can be found in a new book – Trees of Arunachal Pradesh. The 591-page book, a first of its kind, is a collection of the wild, indigenous trees found in the lower elevations of the Pakke Tiger Reserve in the western part of the state. The field guide has been compiled by Navendu Page of the Wildlife Institute of India and Nature Conservation Foundation’s Aparajita Datta and Bibidishananda Basu, and illustrated beautifully by Meena Subramaniam. It provides details and illustrations of 241 tree species, their local names and how to identify a species by its leaves, flower or fruit.
Although the work on the book started in 2019, Page and Datta visited the state several times before. In fact, Datta has been researching on hornbills and conservation projects for local communities in Arunachal Pradesh since 1995. For Page, his interest in the state's floral diversity was piqued by the fact that not there were no books on it.
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Meanwhile, Datta was starting to document the phenology of plants (seasonal recurrences in plants) in the Pakke Tiger Reserve. “Hornbills eat a variety of fruits and so, it was important to understand the plants they fed on,” Page explains. This prompted Page to discuss and collaborate with Datta on a book on the trees of the region.
“There are no field guides for plants in the region like we find for birds," he says, adding that the inspiration for their book came from another similar field guide – Pradip Kishen's Jungle Trees of Central India: A field Guide for Tree Spotters, which came out around 2014.
Arunachal has the second highest forest cover (79.6% of the state is covered by forests) in India after Madhya Pradesh. However, this forest cover has reduced to 74%, as per the Global Forest Watch (2020).
The state has over 6,000 plant species that cover various elevation ranges from lowland to Himalayan vegetation. Out of this, more than 500 species have been identified as medicinal plants till now.
Given the vast forest area, the trio decided to focus on lower elevation forest trees for the book. The book meticulously details commonly found native species along with photos and illustrations that can particularly be useful for laymen. The use of local names of trees in the book also makes it relatable to the local communities.
With citizen science initiatives around trees and fauna picking up in the last few years, Page felt it was important to have a field guide of the region that provided information beyond just photographs. He hopes the book will be useful for botany students, forest department officials, naturalists, and enthusiasts who likes plants and trees.
One of the challenges, Page felt, was the lack of information and documentation of the local tree diversity in the state. While the team has identified and recorded two threatened species in the book, information regarding trees is dismal in the country. “We don’t have any systemic data of threat status of trees; there is a data deficiency. So, we don’t know if there are other trees that are endangered,” he says.