Biodiversity and composition of understory plant communities in the boreal mixedwood forest

林下植物群落（灌木和生长在树冠下的非木本植物）是森林生物多样性的重要组成部分。它为各种生物提供了栖息地，是生态系统进程的驱动力。在森林中，冠层树木通过直接竞争和对林下植物重要的环境条件的影响（例如，微型基地的建立，土壤pH值和养分供应，小气候）。树木也可以影响火灾干扰的严重程度，这反过来又会影响火灾后重建的林下植物。在加拿大西部北方平原的梅西奇地区，森林主要由颤抖的白杨和白色云杉的不同组合组成。这两个树种不同的影响火灾的严重程度和林下环境条件。因此，它们的相对丰富度对混交林景观中林下植物群落的组成和生物多样性具有重要意义。

The understory plant community (shrubs and non-woody plants growing under canopy trees) is an important component of forest biodiversity. It provides habitat for a diversity of living organisms and is a driver of ecosystem processes. In forests, canopy trees influence the understory through direct competition and also through effects on environmental conditions important for understory plants (e.g., microsites for establishment, soil pH and nutrient availability, microclimate). Trees can also influence the severity of disturbance by fire, which in turn affects post-fire redevelopment of the understory. On mesic sites in the boreal plain of western Canada forests are dominated by varying combinations of trembling aspen and white spruce. These two tree species differ in their effects on fire severity and on environmental conditions for the understory. Their relative abundance, therefore, has important implications for the composition and biodiversity of understory plant communities in mixedwood landscapes.