understorey

Tropical forest is wetter and usually supports only knee-high fires that spread slowly through the understorey.

热带则较为潮湿，通常只能使火烧到及膝高度，并缓慢地在下层植物中蔓延。

Forests are important habitats for birds and, in temperate forests, small mammals which inhabit the dense understorey.

鸟类来说是重要栖地，而且在温带里，哺乳动物居住在稠密下层。