This contribution describes the development and current status of a new forest observational study (FOS) network for China.We outline assessment methods,report scientific activities and explain longterm objectives of the network.The FOS sites include large managed and unmanaged experiments,some covering more than 40 ha.They are designed to study ecosystem structure and dynamics,inluding tree growth,recruitment and mortality.The focus in the unmanaged series is on a wide range of topics that are of interest to ecologists,such as species-habitat associations;gender-related biomass partitioning; natural ecosystem structure and diversity; response to natural disturbances including wildfire or seed dispersion and seedling survival.The development in the managed experimentsis characterized by regular selective harvesting activities to assess and analyse modifications of ecosystem structure and diversity caused by harvest events and to study forest dynamics under management.Eachobservational study is subdivided into square cells measuring 20×20meach.The relative height differences among all the intersections of grid linesare assessed to study topographical effects.All trees and shrubs exceeding 1cm in breast height diameter (dbh)are tagged and mapped,their species identified andtheir diameter at breast height,total height and crown diameter measured.Assessments are not limited to measuring trees.Flowers and fruits of dioecious tree and shrub species are collected,tree ring data are assessed,seeds and seedling survivals are counted,biomass components are sampled and the response of the leaf spectral reflectance to aboveand belowground competition is studied under field conditions.An important longterm objective of the network is to attract scholars from a variety of disciplines and from different countries.Currently,working relationships have been established with the University of Quebec,Canada,the University of West Virginia,USA,and the University of G(o)ttingen,Germany.Trees live much longer than most animal and other plant species,and their longevity requires relatively long observation periods.Thus,forest observational studies typically extend over many generations of researchers.For this reason,longterm institutional support is essential.Maintenance and extension of the new forest observational network is currently secured for periods up to 5 years in accordance with the five-year plans of the Peoples Republic of China and its economic development guidelines.Additional support is secured from time to time by short-term projects extending over periods of 1-2 years.Because of the enormous size of the network and the country-wide coverage of virtually all the important forest ecosystems,institutional support is required to ensure the survival of this unique "Green Infrastructure" for future generations.