Nitrogen fixing trees crucial in tropical forests (journal)

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

This study identifies a powerful feedback mechanism in which N₂ fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in young tropical forests. Over a 300-year chronosequence in Panama, N₂-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours, and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000 kg carbon per hectare) in young forests. These findings show that symbiotic N₂ fixation can have a central role in nitrogen cycling during tropical forest development.