You may have heard the buzz: tropical rainforests are repairing themselves far faster than expected. Time for a big party?
Keep the champagne corked for now. It’s true that research by the Carnegie Institution points to some 135,000 square miles of tropical rainforest growing back, but this deserves some context. For a start, that’s less than 2% of the original forest coverage. Also, all this regrowth is an interrupted ecosystem – razed forests that for a time couldn’t perform their vital role as the lungs of our planet. (More on the implications of that in a minute.)
And there’s the vital question of carbon storage. Determining how much carbon young trees lock up has been a recent hot topic – during its development, a new tree takes in more carbon than an older one, and so a new forest absorbs carbon at a quicker rate. Until recently it was also presumed that as forests became elderly there was a “drop-off point” beyond which their carbon storing abilities were severely diminished – implying that planting new forests was the quickest and most effective way to combat global warming. Yet a recent anaylsis by Nature has overturned this – concluding that old growth forests remained sprightly “carbon sinks” well beyond the century-old mark.
Chopping down a rainforest, no matter how quickly it grows back, is opening Pandora’s box.
First, there’s the enormous release of carbon into the environment from all the decomposing vegetation. According to the Wilderness Society, trees in the U.S. alone hold the equivalent of 20 years of American greenhouse gas emissions.
Deforestation is also the loss of a habitat, and even if it’s temporary, some species can’t survive such upheaval.
Regrowth has its own problems – it’s decades before new trees start fulfilling their carbon-sinking potential.
It seems that by far the best way to help forests clean our atmosphere is to simply let them get on with it. For our own good, forests should be allowed to grow old.
A world where conservation techniques do work, coupled with a natural world much tougher than we expected? Maybe we’ll crack open that bubbly after all.
Image: baxterclaws