KARACHI: The beautiful barna trees — among the many indigenous plants that seldom receive government attention during its plantation campaigns — can be an excellent choice for a city like Karachi experiencing a rise in temperature as well as a loss of faunal diversity, experts suggested on Thursday.

The trees in bloom these days attracted many insects including butterflies and their seeds were eaten by birds, they said.

Its botanic name, according to the Flora of Pakistan, is Crataeva adansonii.

“They have a tremendous aesthetic appeal when they flower as they have abundant white to violet petals with a large number of long stamens. That’s why they are grown along streets and avenues,” said Prof Zafar Iqbal Shams, a senior Karachi University (KU) teacher with a doctorate in environmental sciences.

Although studies had shown the many benefits of growing indigenous plants, they were generally ignored in our plantation campaigns, which targeted exotic species, he regretted. Neem was perhaps the only local tree that had received state attention and had been planted in significant numbers, he said.

“But the practice of monoculture is not a healthy trend and experts are of the opinion that there should be diversity in plantation as it brings more resilience and sustainability.”

Plantation drives should be a combination of indigenous and local trees and needed to be done scientifically, keeping in view land conditions, plant requirements, its growth, especially penetration of its roots that could affect water and sewerage lines and the maximum height the plant could attain, he added.

“The best location for barna is a park where it could receive water according to its requirements, though it can also be grown in the wide median running along the roads. Unlike other global cities where tree initiatives are spread over years, for instance the million-tree campaign of Los Angeles which will complete in 2017, our practice is to plant hundreds of saplings in a day or two and that’s the end of the matter,” he lamented.

According to him, some of the local trees that should be given preference in plantation campaigns are banyan tree, peepal, tamarind, amaltas (Cassia fistula), moringa and acacia trees.

A KU study conducted last year to assess the diversity, density and composition of street trees in the 18 towns of Karachi showed that Barna plant existed only in three towns: Liaquatabad town, Gulshan town and Jamshed town (the sampling technique covered about 10 per cent of the streets of each town).

“These plants are still seen in the city but their number has drastically come down thanks to the local authorities that preferred the exotic Conocarpus erectus and Guaiacum officinale (lignum) species in their plantation drives, which have naturally reduced their number over the past few decades,” he said.

Increasing pollution had badly affected flowering and leaf emergence in plants growing along city roads, he pointed out.

On the distribution of the barna tree, he said it was naturally distributed from the Indian subcontinent to the Far East, where it was found in open forests or scrub jungles, except in the humid hill states of North-east India and Kashmir.

“Its wood is used to make agricultural tools while other parts have been found to have many medicinal (anti-inflammatory, diuretic, lithontriptic and demulcent) properties. Fresh leaves and bark have been found to be effective in treating rheumatic and urinary complaints,” he said.

On the nature of barna tree also called sacred garlic pear and temple plant, Dr Farhat Agha, a senior botany teacher, also representing the Horticultural Society of Pakistan (HSP), said the plants shed their leaves during winters, which started appearing during February just before the flowering seasons.

“There are many places in the city where barna trees are still found but I have no idea how old they are. We have four trees in the HSP garden centre, there are some in DHA phases 1 and 4, along Kashmir Road and M.A. Jinnah Road and in the Gurumandir and Patel Para areas.

“However, perhaps, the most beautiful ones are grown along Governor House which were planted by the late A. K. Khan sahib and his team,” she said.

The plant, she said, didn’t disturb neighbouring plants. “It’s leafless from November till March and then starts blooming but usually flowers are more than leaves. Blooming stays till April depending how windy Karachi is in those days.”

Published in Dawn, April 15th, 2016