Cars, Cherry Trees, Chiswick and Carbon
The last-minute cancellation of the planting of 16 cherry trees on Turnham Green, the unfortunate saga that has become known as ‘cherrygate’ got me thinking about carbon capture by trees. How much do trees actually mitigate climate change and how much carbon do they absorb? What was the effect of Councillor Biddolph's last-minute intervention to stop the planting in environmental terms?I should declare my conflict of interest as ownership and occasional use of a family car as well as regular cyclist.I’ve posted recently on here about cars and Chiswick. I wonder why we have to put up with quite so much motorised traffic on the Chiswick High Road, when a much of it is travelling through our neck of the woods to avoid congestion on the A4 and A40 and contributing nothing to the local economy, whilst making the place noisy, polluted, more dangerous and less pleasant. Similarly why do we put up at all with cut through traffic in the roads where many of us live, our residential side streets. Side streets could be turned in to low-traffic neighbourhoods which could be driven in and out of and through. Perhaps Kings Street and Chiswick High Road could be restricted more to local Hammersmith/ Chiswick/ Brentford traffic and electric buses.Anyway back to trees:According to an academic article in ‘Forestry’ in 1999, The average car (driving 12,000 miles a year) then produced 1.1 tonnes of carbon a year. And interestingly real world emissions from cars has only reduced slightly since then then, perhaps because larger cars are more fashionable. (see Chiswick)The author calculates that to absorb the annual carbon emissions from the average car, THIRTY-TWO widely-spaced wild cherry trees would be required. Thirty-eight oak trees would do the same or forty-two poplars. So on Turnham Green, if the donated sixteen cherry trees had been planted as agreed by the Friends of Turnham Green, and they has similar capacity, they would have absorbed about half the CO2 produced by an average family car per year and would have done the equivalent of this every year for about 45 years.We’ve got a couple of cherry trees in our garden which we love (sadly not big enough to be widely-spaced, but never mind). So assuming roughly the same CO2 absorbing capacity this gives me roughly 750km (466miles) of car driving a year. This highlighted a couple of things to me. Firstly that Councillor Biddolph’s cancelling of the planting has prevented the carbon offsetting over the trees over their lifetime of the equivalent of driving a one family car for about 20 years.Secondly that quite that a lot of trees are actually required to offset the average car, so obviously it’s best not to drive or catch Ubers if other options are easily available. A third of trips by car in London are under 2 kilometres and one in seven under 1 kilometer (which takes about 10 minutes for someone healthy to walk) so the message needs to gain a bit more traction.Just for fun and giving the cherrygate councillor's previous hostility to people cycling and protected cycle paths: The CO2 emissions from cycling are approximately 5% of those of driving. The carbon dioxide in this situation comes from the fuel used to power muscles i.e. food (and methane from animal and human guts!) So we can calculate that 16 cherry trees would offset the carbon produced by one person cycling 120,000 km per year (which is round the world three times) or alternatively 16 cherry trees can offset carbon emissions for about 50 people cycling into central London and back daily Monday to Friday for 42 weeks a year.
Edward Seaton ● 2446d35 Comments