ABSTRACT
Detailed knowledge of the interactions between the atmosphere, biosphere and pedosphere is essential for an understanding of global carbon dynamics in terrestrial ecosystems. This chapter addresses ecosystem level variation of Δe, possible impacts of seasonality, of characteristic features of the dominant plant species within an ecosystem (life form, canopy structure, age) as well as the influence of climate and soil nutrient availability. It focuses on where to obtain tro-pospheric baseline data, and then discuss how to determine 13carbon of respired CO2. Canopy air should be collected dry, and stored in inert flasks that do not leak or exchange CO2, with seals that do not exchange with CO2. Natural landscapes comprise mosaics of evergreen and deciduous ecosystems, most pronounced in temperate and boreal regions. Information about the influence of different life forms on ecophysiological processes is therefore critical for understanding what controls carbon dynamics in evergreen and deciduous forest ecosystems, and how to integrate over diverse regions.
