Left alone, tropical forests heal themselves — invaders fade as the canopy closes

When farmland in the tropics is abandoned, forest creeps back — but so do foreign tree species, and conservationists feared the invaders would take over for good. A team from about 60 institutions, led by Angélica Faria de Resende of the University of São Paulo, read the evidence from 1,561 forest plots across 10 countries of the Americas and found a reassuring pattern, published in Nature Plants: foreign trees surge in the first 10 to 20 years, grabbing the sunlight of open ground — then fade. As native trees grow tall and close the canopy, the shade-loving natives take over and the invaders dwindle to low numbers. In humid forests the early wave was big — 28% of trunks — yet it still receded. 'Natural forest regeneration and relatively intact landscapes provide a nature-based solution for controlling non-native species while protecting biodiversity,' Resende concludes. In plain terms: given time and protection, the forest sorts itself out.

SDG 15 · Life on land