Can rainforests regenerate?
We’re still not entirely sure. In 1926, British colonists in Malaysia reseeded (with 15 tree species) an area that had been deforested by mining. A century on, the area looks and feels like a mature, primary forest. However, it hosts only 70 species of tree per hectare, compared to the 200 found in neighbouring old-growth forest.
More recently, a study of 56 sites in tropical America tracked the fates of former agricultural land adjacent to old-growth
forests. Here, tree diversity naturally reached 80 per cent of the natural forests within 20 years, though the actual species present were rather different, and little is known about the recovery of the animal life or the myriad ecological interactions.
That said, perhaps these experiments just haven’t run for long enough. There is evidence that areas of primary forest in both the Amazon and the Congo were cleared for agriculture in the more distant past. SB