Tree age provides an insight into the overall status of the forest ecosystem: seedling regeneration and establishment to maturity determines ongoing survival of the forest and senescent trees often support important specialist biodiversity (Gao et al. 2014, Rainey and Holmes 2023).
There is extensive evidence that tree diversity is a key driver of biodiversity and ecosystem functioning (Baeten et al. 2019, van der Plas et al. 2016, Ampoorter et al. 2020). For example, forests with a higher tree species richness have a higher richness of associated lichens and tree species richness in the regeneration layer is positively related to overall richness of other taxa (Storch et al. 2023).
The direction of change in vegetation biomass provides different insights in ecosystem status, depending on the habitat. In grassland, an increase in vegetation biomass is often linked to declines in species richness, for example nutrient addition leads to grass dominance and a decline in species richness in chalk grassland (Willems et al. 1993). In woodland biomass can be used to track biotic (e.g. ash dieback) and physical (e.g. wind-throw disturbance) (Evans et al. 2019).
Structural complexity within habitats is an important determinant of biodiversity. Vegetation structure can be assessed from the habitat level (e.g. vegetation height diversity) to within-plant architecture (e.g. branch density) (Langellotto and Denno 2004).