Table 1. Definitions and measured morphological traits of each understory vegetation group.

Classification	Definition	Morphological trait
Tree	Woody plants with a diameter at breast height of 6 cm or more	Species, Diameter at breast height, Height
Young tree	Woody plants with diameter at breast height of less than 6 cm (or height under 5 m), including saplings and seedlings	Species, Diameter at root collar, Height
Herbaceous layer	Layer of herbaceous plants and ground cover, including grasses, forbs and ferns	Typea, Number of stems, Length of main stem, Height

The herbaceous plant types were classified into herbs and ferns.