Satellite Data-Based Phenological Evaluation of the Nationwide Reforestation of South Korea

Background

South Korea's reforestation efforts since the 1950s have been evaluated for changes in biomass, area and growing stock; but little has been done to study the phenology changes (seasonal changes) and photosynthetic activity, which will help in the preparation of new forest management in light of climate change.

Goals & Methods

This study analyzes nationwide variations in phenology using satellite-based and ground-based growing season estimates from 1982-2005 to answer the question, "Which phenological event, start or end of the growing season, has had the most dominant effects on the recent changes in the total growing season?" The authors used a combination of satellite-based estimates (Global Inventory Monitoring and Modeling Studies) and ground-based estimates of first-flowering date of cherry to study both temporal and spatial variations and the relationship between surface phenology and forest biomass carbon stocks.  

Conclusions & Takeaways

The results show clear geographic variations according to latitude and altitude, and indicate that the growing season has increased by ~4.5 days over the past 27 years, largely due to an increase in the end of the growing season by ~2.5 days. The study also established a statistically significant positive correlation between phenology and biomass carbon density in young forests, which was not true in old forests, suggesting that regions of larger biomass carbon density correspond to longer growing seasons. This could be explained by the fact that younger forests are more responsive to external factors than older forests. Further studies should explore the role of soil dynamics and its relationship to the role of phenology in the terrestrial carbon pool.