Part I: Radiocesium deposition at the accident.- Chapter 1: Radioactive contamination in forest by the accident of Fukushima Daiichi Nuclear Power Plant  - Comparison with Chernobyl-.- Chapter 2: Radiocesium deposition at the accident and the succeeding movement through hydrological process in forest ecosystem in Fukushima.- Part II: Mechanisms of radiocesium translocation in plants.- Chapter 3: Uptake of radiocesium by plants.- Chapter 4: Surface absorption of 137Cs through tree bark.- Chapter 5: Translocation of 137Cs in the woody parts of Sugi (Cryptomeria japonica).- Chapter 6: Radiocesium translocations in bamboos.- Chapter 7: Movement of cesium in model plants.- Part III: Radiocesium movement through ecological processes in forest ecosystem.- Chapter 8: Movement of radiocesium as litterfall in deciduous forests.- Chapter 9: Changes in chemical forms of radiocesium in the forest floor organic matter with decomposition, and uptake of radiocesium derived from the organic matter by crops.- Chapter 10: Contamination and transfer of radio-Cs in soil ecosystem.- Chapter 11: Spiders as an indicator of 137Cs dynamics in the food chains in forests.- Chapter 12: Radioactive cesium contamination of sika deer in Oku-Nikko region of Tochigi Prefecture in Central Japan.- Part IV: Radiocesium dynamics and its perspective in forests.- Chapter 13: Modeling radiocesium dynamics in a contaminated forest in Japan.- Chapter 14: Future perspective.