The cycles of carbon and nutrients involve many ecological processes that are all potentially sensitive to environmental change (Bai et al., 2013; Yue et al.,

2017). Key terrestrial ecosystem processes include photosynthesis, aboveground and belowground plant growth, autotrophic and heterotrophic respiration, organic matter decomposition and nutrient mineralisation. Even minor changes in any of these processes, or in the balance between them, can have implications for ecosystems as well as individual organisms.

Ecosystem responses to environmental changes can affect important services that terrestrial ecosystems provide to humanity, such as provisioning of food and fibre, water regulation, and carbon sequestration (Trumbore et al., 2015). Therefore, the assessment of responses of biogeochemical processes to a changing climate in global-change studies is important from a fundamental and applied perspective.

In the carbon and nutrient cycling chapter, we focus on the main components of the terrestrial carbon cycle, including aboveground and belowground processes, pools, and fluxes. Nutrients are also included, but only those pools and processes that are linked to carbon cycling and ecosystem feedbacks to the climate. We distinguish between plant and soil measurements. We also provide three thematic protocols that are particularly relevant when considering carbon and nutrient cycling processes within terrestrial ecosystems (plants, soil, ecosystem).