Trees are not enough

While recovering from a very minor surgery in hospital, I looked out over the top of a Jamun (Syzygium cumini) tree. Jamun is one of the fastest growing trees of India. In about 6-8 years it grows to a height of about 10 meters, and it lives for about a 100 years. It begins to fruit when it is about 8 years old, and continues to yield a good crop until it is well over 60. I love this fruit, and look forward to the hot time of the year for it. The tree is hardy and grows well enough to be considered invasive in some parts of the world. If you are interested in carbon mitigation through planting trees, this should be a great choice. But how much carbon does it bind?

A decade old tree is about a meter in perimeter, which means that with a height of 10 meters, its volume is 10/(4π) meter³, which is about 0.8 meter³. Jamun is one of the denser woods, with a specific gravity of 0.7. This means that a 10 meter tall tree weighs about half a metric ton. About half the weight of the wood would be carbon (the rest is essentially hydrogen, oxygen and nitrogen). Planting about twelve billion new jamun trees would be sufficient to capture the carbon that India emits in a year, for every year in the next decade or so.

Typically a jamun orchard will have a spacing of about 10 meters between trees. This means that one tree is usually planted in about 100 meter² of area, which is about 10,000 every km². India has an area of 3.2 million km². So planting enough Jamun trees to capture the carbon that we emit would take about 12% of India’s land area. This is a little larger than the area of France. However, this will have to be well drained loamy soil, with sufficient water. That would be about one fifth of the agricultural land in the country.

It already sounds pretty hard. But then I found that an increase in tree cover by 2261 kilometer² in two years was considered celebratory news. This, as you can see from the numbers above, is the area needed for about 0.02% (1 out of every 5000) of the trees one needs to plant! Maybe that means that planting enough trees to mitigate carbon emission is in the realm of pipe dreams. I’ve talked about a fast growing tree, because it would absorb carbon fast. If we take slower growing trees like teak or pine, then we would need to plant more of them to absorb carbon at the same rate.

Trees are good. Trees are healthy. Trees allow other vegetation to grow beneath it. Trees are needed to slowly suck the carbon out of the air. But today’s meditation convinces me that planting trees is no miracle cure to the climate change problem, no more than covering a pot while cooking is a solution. Pollution is a structural problem, and one needs structural changes for that. Making more efficient use of electricity is better. If I had another day in the hospital, I might have been able to calculate how much energy we can save my going off all social media altogether.

And since I’m joining in (against all good sense) to a challenge which asks us to show three photos, I must add that one should extend the title of this post and say that threes are not enough either.

End-summer reds

Right now, as summer turns into monsoon, grishma to varsha, our table is full of red fruits: from the red-orange of ripe apricots to the darker reds of ripe plums. Just to be contrary, I put a couple of left over jamun (Syzygium cumini) in the bowl. Not only does the deep purple of its skin present a counterpoint, so does its taste. The sweetness of the apricots and plums seem bland compared to the tart turning to sweet of jamun. I think this photo could be this year’s goodbye to these fruits, now that three showers a day has announced that the monsoon winds are close to us. The weather is better, but it is the season of grey for the next four months.

The world of woven trees

We still remember, we who dwell
In this far land beneath the trees,
Thy starlight on the Western Seas.

J.R.R.Tolkein, The Lord of the Rings

The season of jamun (Syzygium cumini) came and went again in an eyeblink. It has been a favourite since my childhood, when my friends and I would pick fallen fruit from the ground, and in complete disregard of instructions from parents, eat them without bothering to wash them. Our mouths would turn a bright purple from the juices of the fruit, so there was no hiding the fact that we had spent a morning foraging. My memories have a strange anti-resonance with Tolkein’s verse, equally laden with nostalgia. Sitting on the shore of this western sea, I still remember my childhood in the far land of woven trees. Especially the burning heat of summer holidays, when dogs and their Englishmen dozed in the shade, and only school children and crows would venture outdoors.

Jamun

I managed to taste some jamun (Syzygium cumini) at the tail end of the season. This is a fruit which is deeply embedded in my childhood memories. I literally measured my growth by a jamun tree which stood in the garden in front of the house I grew up in. My earliest memories of the fruit are of picking fallen jamun and eating them until my mouth and tongue were stained deep purple. Every summer, over years, my cousins and I tried to climb the tree. Eventually I was able to shin up that straight scaly trunk until the first branch. I was never as good at it as a friend who would go straight up to the fruiting branches and drop fruits down on the rest of us after eating his fill. I wasn’t surprised to find that this tree is native to the Indian subcontinent. Unlike the mango, another fruit of the summer, there is no mystique to this fruit; it is just an old friend, a favourite which you love to come back to. This year too, The Family and I sat down to savour the sweet acidic taste of the fruit, and shared childhood memories of having it with rock salt.

That’s why I was not surprised to find that there is huge genetic variation in the tree across India; no one has tried to cultivate particular strains. Since the taste of the fruit is preserved by the seed, vegetative propagation of jamun has not been widely used. Propagation by seed must have caused some selective distinctions between different regional varieties (the ones we ate this year did not colour our tongues much) while retaining genetic diversity. Two related facts amazed me. First, that although jamun has been carried across the world recently, there are many regions where the fruit is grown but not eaten (imagine that!). Second, that the genus Syzygium is found in a wide arc across the world, from Africa and Madagascar, through Asia, all the way to Australia and several Pacific islands. The geographic spread and genetic clocks indicate that the genus may have evolved after the late Jurassic, when the supercontinent of Gondwanaland was breaking up to create the modern oceans. It contains more than 1500 species, many of which have edible fruits, and (this blew me right out of the water) cloves (Syzygium aromaticum) belong to the same genus.