The understory is a unique environment, involving more than just shade. Shade influences air temperature, humidity, soil temperature, soil moisture content, wind movement, and more. These factors impact plants. (Agroforestry ejournal)

Savanna trees influence water, light, and nutrient availability under their canopies, but the relative importance of these resources to understory plants is not well understood. (CAT.INIST)

Understory vegetation responded to thinning with increased percentage of cover and number of herbaceous species in thinned areas and in created gaps. (US Forest Service)