Ron Dembo of Zerofootprint posts engagingly at TreeHugger on, well, the value of trees:
The role of trees is essential to the health of the planet’s ecosystems, while their benefits so multifarious that we really cannot have enough of them. Everyone knows of the gifts of the trees in their neighbourhoods, whether it is the beauty and shade they offer, the protection from wind or flood, their flowers and fruit, their habitat for wildlife, their wood, their sap, or the playgrounds they provide for children.
Cities are beginning to realise that their trees have a quantifiable value. New York’s parks department, for example, has concluded that its street trees provided an annual benefit of about $122m, or $5.60 in benefits for every dollar spent, through their ability to combat pollution, reduce noise, prevent flash floods, add value real estate, and so on.
With one fifth of global emissions down to deforestation, we need to do everything we can to protect existing forests, while given the benefits of trees over and above their carbon sequestration, we need to plant as many as possible.
Everything about this is true and (re)forestation is extremely useful and important as both an environmental and an economic move on its own merits. But Dembo is ostensibly writing about using trees as carbon offsets, and doesn’t quite answer his own questions: “Why offset with trees when fossil fuels are to blame? … Shouldn’t we focus on renewable energy projects that can replace the use of fossil fuel?”
And the answer is that as far as reducing atmospheric carbon levels is concerned, we actually should focus on (1) using less energy, (2) getting energy from renewable sources, (3) reducing the carbon we emit from burning fossil fuels, and (4) trying to take carbon out of the atmosphere — in that order.
Once we’ve squeezed enough benefits out of one item on the list that we’re seeing diminishing returns, then we can move on to the next. Compare it to trying to put out a fire; the first thing you do is stop throwing gasoline on it, before you start dousing it with water.
Dembo also handwaves away the very significant practical problems we currently have with growing trees as carbon offsets, namely that it’s hard to be sure just how much carbon they’re fixing out of the atmosphere, hard to protect trees from being cut down or dying natural deaths later, and hard to be sure that any particular company is actually planting and managing the trees it says it is.
Again: reforestation is very, very good and worth pursuing, but getting it mixed up with the carbon-offset business means confusing both goals.