Global warming is caused mainly by gases such as carbon monoxide and dioxide in the atmosphere. This is a fact now known to everyone except only the stupidest among us. During hours of daylight, foliage captures oxides of carbon and water from the air. Chlorophyll, the substance that makes leaves green, uses sunlight to process the oxides and moisture into sugar for the tree’s food and releases the oxygen back into the air. This process is called photosynthesis.
The less carbon in the atmosphere, the cooler the earth’s temperature. That is an unalterable scientific fact. However, the process of photosynthesis slows down considerably during hours of darkness.
Now, the larger the biomass of the tree, the more carbon it will sequester. A mature banyan or pipal will hold far more carbon than, say, an ornamental rubber plant or even a fully grown date palm. It can hardly be overemphasised that trees of large biomass have the capacity to limit global warming. Moreover, the fact that our planners forever miss is that Pakistan is a hot country where we need shade. Palm trees and bushes are a poor choice for that.
Recent research shows that pipal (Ficus religiosa) is perhaps the only tree in the world that continues to release oxygen even in darkness. No wonder ancient Indians worshipped this wonder tree! This is the most beneficial tree if humans are serious in their attempts to control global warming.
This does not mean that simply planting countless pipal trees will halt the spread of greenhouse gases even when we do not take other measures as laid down under the Kyoto Protocol. But pipal can certainly help.
For more than two decades I have cried myself hoarse about the need to keep our foliage indigenous. But we who learn horticulture from our illiterate malis have no sense. The loss: Lahore’s bird life. Forty years ago an estimated 170 species of birds were resident in the city. Today we have less than 50. And these few are restricted to Raj period plantations such as Lawrence Garden, Mayo Gardens, Aitchison College and the cantonment.
There are attempts by ignorant babus and their political masters to turn Lahore green. But, mark my words; this will only be a green desert where no birdsong other than the cawing of crows will ever be heard. — S.R.
Published in Dawn, EOS, May 14th, 2017