Short‐term responses in a secondary tropical forest after a severe windstorm event

Abstract

AbstractQuestionsHow do abiotic conditions, forest structure, as well as taxonomic and functional diversities and composition recover after wind‐generated treefalls? Do young and old‐growth secondary forests differ in their responses?LocationMandai region of the Central Catchment Nature Reserve, Singapore, where extensive treefalls occurred during an unusually powerful windstorm in 2011. Southeast Asia.MethodsSoil nitrogen, phosphorous, potassium, canopy cover, leaf litter depth, coarse woody debris, and woody stems ≥1‐cm diameter were measured and identified in 10 × 10 m plots. Twenty‐six plots were located in treefall areas and 14 plots were located in relatively unaffected areas, with equal numbers in young and old‐growth secondary forest types. The first round of surveys took place within 3–6 months of the windstorm event and yearly re‐surveys were conducted until 2015. Specific leaf area, leaf dry matter content, leaf thickness, woody density, maximum plant height, and seed dry mass were measured or derived from various sources.ResultsThere was a pulse of soil nutrient availability in both affected and unaffected areas 1 year after the wind event. Canopy cover and basal area in the affected areas recovered to similar levels as unaffected areas by the second year, and coarse woody debris by the fourth year. In affected plots, taxonomic and functional diversities increased and overshot that of—and taxonomic composition diverged from—unaffected plots after the second year. Young and old‐growth secondary forest types mainly differed in the taxonomic composition of new recruits. However, there was no evidence of changes in functional composition towards resource‐acquisitive strategies such as lower wood density or higher specific leaf area.ConclusionsAbiotic conditions and basal area recovered rapidly within 2–4 years after the windstorm. Taxonomic composition in young and old‐growth affected forests both diverged from unaffected forests but also from each other over time.