Alnus formosana, the Formosan alder, is a species of alder endemic to Taiwan. It is a medium-sized tree, up to in height It is commonly found in disturbed habitats as a pioneer species.
Ecology
Alnus formosana flowers between May–June, fruiting between July–September.
The Atayal people uses A. formosana as a cover crop after clearing a new field, the traditional wisdom being that the soil becomes rich when it is cut cleared again in 10 to 15 years. It is also used in the Pas-ta'ai ritual of the Saisiyat people.
Early Han settlers of Taiwan name some places after the occurrence of the plant, the belief being that its occurrence is linked to ground collapse.