Climate News Network

Computer census aids declining palm trees

July 28, 2017, by Paul Brown

Palmyra palms galore line a road in Tamil Nadu, India.
Image: By PJeganathan via Wikimedia Commons

Concerned that palm trees vital to his home country are vanishing in large numbers, a scientist has devised how to count them for conservation.

LONDON, 28 July, 2017 – A method of counting palm trees by using images on Google Earth is being used to plot the decline of valuable trees across large tracts of dry land in the tropics.

The project was initially launched to raise awareness of the decline of the Palmyra palmBorassus flabellifer, in northern Sri Lanka, but the method can be used to count any palm or coconut species for a census of tree numbers.

It is 93% accurate and will save both time and many hours of work, because the alternative is manual counting from the ground. The idea is to document the decline of trees and identify areas where new plantations can be introduced.

The Palmyra palm, a 100-ft (30 m) giant, has many uses, including as a roofing material for millions of people, and has been a vital resource for generations. There are as many as 40 million specimens in the Indian state of Tamil Nadu alone. Across the narrow strait in northern Sri Lanka, however, numbers have diminished substantially because of the country’s civil war, and human development.

Shade givers

Senthan Mathavan, a visiting research fellow of the School of Architecture, Design and the Built Environment at Nottingham Trent University, UK, is from Jaffna in northern Sri Lanka. He has watched the decline of the species with sadness. He said: “Even two decades ago, every backyard used to have five to 10 trees, and these provided the much-needed shade in the hotter months. This has become a rarity now.”

Outside developed areas there were groves of the trees. All tree cover has a cooling effect on the climate, and here the summer heat is becoming an increasing problem. “For me this is about using the technology I know very well to solve a problem that is going to change the landscape of the region I was born in,” said Dr Mathavan.

The system can be adapted to count other tree species with similar characteristics and to help formulate conservation programmes. The counts are being done in collaboration with the National University of Science and Technology (NUST) in Pakistan, where the trees are also a valuable resource.

Co-investigator Dr Khurram Kamal of NUST said: “It’s important that we’re able to gather reliable data on the decline of these trees to help ensure that something is done to mitigate their decreasing numbers.”

The Palmyra palm is distinguished by its blue-green fronds, which grow in a circular pattern, and its impressive height, which casts a distinctive shadow. Because the trees grow on dry land and a distance apart, it is possible using freely available Google Earth maps to do an accurate count.

“It’s important that we’re able to gather reliable data on the decline of these trees to help ensure that something is done”

The Palmyra palm has never been planted traditionally because it regenerates itself from seed, and local people have allowed them to grow. The fruit is eaten raw and used as an additive for food. It can be boiled, beaten and made into a flour that is high in nutrients and is added to rice to made traditional dishes.

Palm shoots from the top of the tree are also used to make drinks, some of them alcoholic. A non-fermented drink is made into palm sugar, which is said to have medicinal properties.   The wood for building and the palm leaves make particularly good thatch and are used on millions of poor people’s homes.

However, in many places the trees have been cleared for development or replaced by coconut palms, which are used for a cash crop.

The Sri Lankan government-backed Palmyrah Development Board hopes the survey will help it to promote a tree-planting programme. – Climate News Network

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