On the tree-root-soil-continuum - temporal and spatial coupling of the belowground carbon flux

摘要: The direct flux of current assimilates from the tree canopy to belowground compartment drives roughly half soil respiratory activity in boreal forests. This thesis focuses on temporal and spatial aspects carbon (C) within tree-root-soil continuum temperate I used stable isotopes 13C 15N follow C flow nitrogen reverse direction. isotope composition photosynthate varies diurnally, but such variations could not be observed soil-respired CO2. Labelling small (up 4.5 m) Pinus sylvestris trees with 13CO2 showed that it took two days for reach soil. velocity phloem was c. 0.1 m h-1. is absolutely vital production sporocarps by ectomycorrhizal fungi, as shown their paucity plots girdled trees. It also likely important other microorganisms; addition a labile labelled source revealed lack substrates plots. reduction abundance edges centre uptake experiment lateral spread roots average 4 5 trunks. Thus, can expected an area 60 m2 under influence single tree. Areas several overlapped. conclude processes are coupled time lags few days. impact plant should considered more often studies labelling study demonstrated now possible at very high resolution fate this into system.