Applying biomass and stem fluxes to quantify temporal and spatial fluctuations of an old-growth forest in disturbance
- 1South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China
- 3Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
- 4Barr Engineering, Minneapolis, Minnesota, 55435, USA
- 5Climatic and Agrometeorological Center of Guangdong Province, Guangzhou 510080, China
- 6Department of Plant Ecology, University of Bayreuth, 95440 Bayreuth, Germany
- *These authors contribute equally to this work.
Abstract. A subtropical old-growth forest was studied over a twelve-year period to investigate temporal and spatial fluctuations of biomass and stem fluxes under disturbances. Vegetations were categorized into three types according to disturbances caused by biotic and abiotic factors, including Castanopsis chinensis population, insect direct-influenced population, and insect indirect-influenced population according to disturbance scenarios. The biomass fluxes (growth and mortality) and stem fluxes (stem recruitment and mortality) were used to quantify population fluctuations. Annual average biomass growth rate was stable throughout the study while annual biomass mortality and stem fluxes increased consistently. C. chinensis population predominantly contributed to biomass fluxes of the community. Biomass and stem mortalities of insect direct-influenced population increased significantly during the whole study period (1992–2004). Results of indirect-influenced population showed that (1) the increase in biomass of the dominant species was well correlated between different intervals. Similar relationships were found in stem fluxes; (2) higher stem mortality occurred within the DBH range of 1 to 10 cm; (3) stem fluxes in the canopy gaps were remarkably higher than those in closed canopy.