Tropical Seasonal Forest

Abstract

Most seasonal tropical forests average ≥650mmrainyear−1 and ≤200mm rain during the year's driest quarter. Their wetter counterpart, rainforests (everwet or aseasonal forests) average ≥1700mmrainyear−1, ≥300mm in the year's driest quarter, no month averaging <80mm rain, and no. 2 consecutive months averaging <100mm rain. Tropical seasonal forests include humid forests, averaging ≥1700mmrainyear−1, ≥100mmmonth−1 for at least 7months of the year, and ≥50mm in the year's driest quarter, and dry seasonal forests averaging <1700mmrainyear−1, and usually, ≥5 consecutive months averaging <100mm rain apiece. Zones of rapid species turnover between everwet and seasonal forest reveal trade-offs between adaptation for everwet versus seasonal climate. The distinction between humid and dry seasonal forest is far less clear-cut. Especially in everwet and humid seasonal climates, continental forests with more rain during the year's driest quarter have higher tree diversity. Even mildly seasonal forests have a much more markedly seasonal rhythm in flowering, fruiting and leaf flush than aseasonal forests. Thanks to their manageable tree diversity, seasonal forests have contributed disproportionately to our understanding of processes organizing tropical forest ecosystems.