It's not quite the Amazon rainforest, but Britain's tree canopy is a vital asset. Lucy Siegle on why, and how, we should protect it.

 

 In the popular imagination, big trees equal trouble. Among the plethora of problems they supposedly cause is the downright irresponsible shedding of fruit (Islington council has taken umbrage at dangerous pear trees) and conkers (Norwich council found the conker-dropping antics of 20 horse chestnuts intolerable), and leaves that make pavements slippery.

But mostly it's about their roots (outrageously) seeking water, pushing up pavements and wantonly destroying the foundations of houses. Such bad behaviour is punishable, it seems, by tree death: out of 40,000 trees felled by London boroughs in the past five years, subsidence was cited as the reason in 40 per cent of cases.

According to a London Assembly report last year, unequivocally entitled Chainsaw Massacre, only 1 per cent of these fellings were justified, subsidence being a complex kind of problem. The London Tree and Woodland Framework agrees that the allegations of subsidence are more severe than the reality. Naturally, the insurance industry is loath to admit that it might be axe-happy, and insists that since May it has enforced an industry standard, Root Mitigation Protocol - and unless a tree meets the standards therein it cannot be removed. If you are still convinced that a municipal tree should not be removed, lobby the council for a Tree Preservation Order (gardenlaw.co.uk).

Britain continues to lose its veteran tree canopy, opting instead for mass planting of lollipop trees - smaller, more compact varieties with shorter root systems. These are reckoned to be cheaper because they require less maintenance, but this is a false economy. Preserving the big tree canopy of the UK might not be in the same eco-crisis league as preserving the Amazon rainforest, but it is short-sighted to ignore the merits of big trees: they clean air, capturing molecules of pollution; absorb CO2 while giving off oxygen; act as sound and wind barriers; cool heated cities; help prevent erosion and moderate and lessen flow of rain to storm drains (the latter two attributes are, frankly, things you'd expect to thrill the insurance industry).

But big trees shouldn't be regarded as priceless. Indeed, one way to save them is to put a cold, hard cash value on them. Andy Tipping of the London Tree Officers Association has come up with a formula, the Capital Asset Value for Amenity Trees system (Cavat), which comes up with an approximate value based on the size of the trunk, height, condition and the number of people the tree serves. Britain's most expensive tree is valued at £750,000 and it's a Victorian beauty in the middle of Berkeley Square in Mayfair. Why is Cavat a useful development? Because the good thing is, unlike its poor Amazonian cousins, the Mayfair tree is worth more alive, growing and untroubled than dead and turned into floorcovering.

This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.

Do the right thing

Plastic litter on beaches was up 58 per cent last year. The new big culprit: plastic tampon applicators. Go for traditional cardboard or buy a Mooncup (mooncup.co.uk)

Lucy Siegle writes the Ethical Living column in the Observer magazine and is a regular presenter on BBC’s The One Show.

Her new book, To Die For: Is Fashion Wearing Out the World? is due to be published in January 2009.