Temporal Variation and Hysteresis of Soil Respiration and Sap Flow of Pinus densiflora in a Cool Temperate Forest, Japan

Soil respiration (Rs) consists of autotrophic (Ra) and heterotrophic (Rh) respiration, the metabolic responses Ra Rh are supposedly affected by environmental factors. Our hypothesis was that contribution would be seasons. To characterize seasonal patterns Rs, sap flow (as an indicator photosynthetic activity), factors, we continuously measured temporal variation in Rs using automated opening closing chamber system a cool temperate forest. had counterclockwise hysteresis (Rs: spring < autumn) with soil temperature at depth 5 cm. Daily maximum significant positive relationship daily over three seasons, lower autumn than (Ra: > autumn). The amount leaf litterfall increased significantly from August to October; high due increase (Rh: These results suggest contributes more autumn, is summer through autumn.