It's hard not to join in the chants when they come to town - mainly because it's something of a no-brainer. Old growth forests, those mythic stands of trees, whatever species they may be (if we even care in the first place what species they are), touch something deep within us that compel us to argue for them to be conserved, protected and revered. We don't care for definitions, all we care is that they're old, they're forests, and they're safely locked in reserves far from the touch of humankind.
It's a noble cause, and to paraphrase the eminent Victorian forest ecologist David Lindenmayer, we are living in a time when we shouldn't have to log or destroy our old growth forests. It is a mark of the truly civilised society, then, that the soil shall never shake with the vibration of a falling giant ever again.
But there is a question that hangs over these presumptions that no one seems to consider - what happens when the old growth dies, of natural causes? In the case of Australian old growth, the majestic Eucalyptus regnans tends to live for around 400 years - dwarfed by the 2,200 years of it's rival-in-height, Sequoia sempervirens. Are we prepared to let go of old-growth, if that loss occurs free of the hand of man or bushfire?
It's a tricky argument, and you're not likely to garner many friends (of the earth - ha!) while pursuing it - it is too easy a sentiment to be appropriated by anti-conservationists as an argument for no-holds-barred native forest harvesting. However, there needs to be a level of reconsideration when it comes to old-growth forests. As Tim Low pointed out in his 2003 novel 'The New Nature', the notion of wilderness can, at times, be an unhelpful idea - potentially even a "dangerous myth", one of the "biggest buzz words in history", an "idealised view of nature [speaking] strongly to people disillusioned with city values."
In my interpretation, the most dangerous thing about "wilderness" is that it exiles nature to that which lives outside the city limits. And thus, everything in and around our suburban gardens, city streets, and rivers - indeed, all that is closest to our hearts and homes - aren't given the due weight they deserve. This is particularly so in the case of the urban forest.
In 2007, Randy Stringer from the University of Adelaide presented a paper at the annual Treenet Symposium titled 'The Benefits of Adelaide's Street Trees Revisited'. Some of his general conclusions included the observation that trees in Adelaide's urban landscape provide not only aesthetic value, but without them, summer temperatures in the city would be 0.5-2.0 degrees Celsius warmer, translating to a per household per year air conditioning energy consumption increase of $20. This occurred alongside stormwater reduction, carbon dioxide sequestration and air pollution reduction.
However, one of the most interesting remarks was that, all in all, older, larger street trees in urban landscapes can provide up to 60 times the benefits of younger smaller trees. Therefore - we need old growth not only in wilderness reserves, but in our cities too. This is a great challenge - it requires our planning to take account the next 50 years, and an intelligent overlap between young trees and old trees to ensure we never end up with barren streets burning in the heat of summer. Furthermore, it requires us to choose trees that will survive the hotter and drier future that awaits us.
But most of all, it is but another reason why we need to realise that we never are, and never will be, distinct and separate from nature. The distinction, if it was ever there at all, is porous and malleable. Nature's heart beats to the same ceaseless rhythm in the misty wilderness reserves as it does in the sprawling metropolis. It's just up to us to listen to it.
