understoreynoun [ C or U ]
UK specialized US understory /ˈʌn.dəˌstɔː.ri//-dɚˌstɔːr.i/a layer of plants and bushes that grows under the canopy (= the thick, high roof formed by branches and leaves) of a forest:
There are many old plants, as well as a thriving understorey of seedlings.
The article examines the effects of surface fires on understorey in central Brazilian Amazonia.