Ross Clark

This manic tree-planting contest has gotten out of hand

This manic tree-planting contest has gotten out of hand
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Whoever wins the election, three things are certain: borrowing is going to rise, taxes are going to have to go up – and there will be a lot more trees. There may even be enough trees to replace those lost to produce all those Lib Dem election leaflets and bogus newspapers.

The election campaign has descended into a manic contest to see who can promise to plant the largest number of trees. The Conservatives have promised 30 million a year for five years, the Lib Dems have upped that to 60 million. The Greens have chipped in with 70 million a year for ten years. Never to be outdone, Labour has promised 100 million trees a year for 20 years. So there.

It is all beginning to look like a Monty Python sketch. That’s nothing, the Tories should now say: we’re going to plant 10 billion trees, until there is one coming out of every chimney pot. Make that 100 billion, Labour should respond – we’re not stopping until everyone has a tree coming out of their ear’ole.

To put these figures into perspective, and assuming an average planting density of 500 trees per acre, or 300,000 per square mile, the Conservatives are planting to plant around 100 square miles a year. At the end of five years they will have covered the entirety of Berkshire. As for Labour, at the end of its 20 year plan it will have planted 6,000 square miles: an area covering Kent, Surrey, Sussex and Hampshire.

All very green and all very admirable, of course. But it does rather raise the question: where are all these trees going to be planted? These promises, given that environmental issues are a devolved issue, only cover England. England stretches to 50,000 square miles. We are going to struggle to find 6,000 square miles which does not seriously encroach on good quality farmland. Britain’s self-sufficiency in food has already nose-dived over the past two decades. The tree-planting spree could make us further dependent on imported food, colliding head-on with another environmental issue: cutting down food miles. Either that, or we will have to have a Dutch-style revolution where we grow much more of our food in large greenhouses, hydroponically – without soil. That has a lot to say for it, but I don’t hear any of the parties talking about it.

The other environmental issue is whether, even with all this tree planting, we would as a nation be making a net contribution to global tree cover. In recent years Britain has become a vast importer of wood pellets, to feed our biomass power stations at Drax and elsewhere. It has allowed the government to claim rapid progress in renewable energy – 30 per cent of electricity is now from ‘renewable sources’. But some forms of electricity are more renewable than others, and there are many critics who object to the inclusion of wood pellet-fired power stations in this definition.

In 2018 we imported seven million tonnes worth of wood pellets, most of which had to make a carbon-hungry journey across the Atlantic from North America. There are conflicting claims as to how much of the content of these wood pellets comes from trimmings – leaves, twigs etc – which would otherwise go to waste and how much comes from virgin wood. But on a crude calculation, taking the weight of a mature pine tree as five tonnes, we are burning about 1.4 million mature trees’ worth of wood a year to feed our biomass power stations. While this is a lot fewer than the number which the parties are promising to plant, you have to remember that their trees will be saplings which will not reach maturity for several decades – and they will need to be thinned out considerably before they do so.

If we are going to rely on wood-burning for our renewable energy, we are going to clear out an awful lot of North American forest land before our Conservative/Lib Dem/Labour forests have reached their prime.