Stem respiration and its linkage with soil respiration

Background/Question/Methods

Stem respiration from forest ecosystem is an important component of total ecosystem respiration and the forest carbon cycle. Our knowledge in understanding the variation in stem respiration and its governing drivers is limited, partially because empirical measurement of stem respiration is scarce. The diel pattern of stem respiration and its linkage with soil respiration and tree photosynthesis are not widely known.

Our research goal is to develop a novel system to automatically measure stem respiration at a half-hour frequency and to explore the diel pattern and its correlation with soil respiration and root respiration. We hypothesize that the peak value of stem respiration during a day reaches earlier than root respiration, resulting from the transit transport of newly assimilated photosynthate.

Results/Conclusions

Our preliminary results indicate that the magnitude of stem respiration based on stem area is at the same order as soil respiration based on ground area. The diel pattern of stem respiration is primarily driven by temperature variation. But the peak stem respiration during the course of a day is influenced by tree photosynthesis.