Abstract: Stem/branch respiration contributes about 8% of the total ecosystem respiration, being one of the most important components of forest carbon budget. In recent 10 years studies, specific respiration chamber with complex system was applied to measure the stem/branch respiration. However, it’s still difficult to precisely estimate the stem/branch respiration at cell, tissue, individual, and stand scales. It is becoming a major trend to estimate the CO₂ flux from the  internal and external stem/branch, using the combination of CO₂ microelectrode technology and infrared gas analyzer (IRGA) method. Generally, the stem/branch respiration rate increases with elevated atmospheric CO₂ concentration and temperature, but it’s still unclear whether the stem/branch　respiration acclimates to the elevated CO₂ concentration and temperature. The Q₁₀ value of stem/branch respiration, ranged from 1.0 to 4.3, could be affected by measurement method, season, tree age, and stem diameter. In addition, the stem/branch respiration rate decreased with increasing drought stress, and increased abruptly with the following rewetting process. The management practices, including fire, fertilization, irrigation, pruning, and girdling, could also affect the stem/branch respiration rate. Therefore, four research priorities were proposed, i.e., 1) sources and fate of the CO₂ release from stem/branch respiration and its measurement standard, 2) biological mechanisms of the responses of stem/branch respiration to environmental change, 3) acclimation of stem/branch respiration to environmental changes, and 4) integrated application of stem sap flow measurement, isotopic tracing, and CO₂ microelectrode technology in measuring stem/branch respiration.

Key words: Global warming, Precipitation, Soil moisture, Productivity