Biogeochemical emissions represent a significant part of the atmospheric sources of major greenhouse gases (CO2, CH4, N2O) and volatile organic molecules. Optical spectroscopy techniques based on absorption of ultraviolet, visible or infrared light are, in principle, valuable analytical tools for measuring the atmospheric minor constituents because the Beer-Lembert’s law relates changes in the light intensity directly to concentrations. There are, however, several challenges to be overcome for instruments that employ absorption spectroscopy to make atmospheric measurements. Most daunting is that often instruments must be able to detect changes in concentration of target species with sensitivities ranging from ppbv to pptv. During recent years, new analytical techniques have been developed that are mainly based on laser spectroscopy. They are not only more sensitive and reach lower detection limits but they also give more detailed information on the species under investigation and their interactions with the environment. In my talk, I will highlight the recent progress in measuring atmospheric trace molecules by ultra high-sensitive laser spectroscopy, and introduce our new combined efforts in laser spectroscopy techniques and biogeochemical studies of trace gas exchange between the atmosphere and biosphere in a forest environment.