Forest degradations including deforestation and desertification are problematic globally as well as expand rapidly. This is true particularly in Asia, Africa and Latin America. Deforestation is also a serious problem to the tropical forest in Southeast Asian regions. Slash and burn, and shifting cultivation are most critical causes for destroying the tropical forests. Similar degradation was observed in Northeast Asian regions: desertification in China and Mongolia, and deforestation in Democratic People's Republic of Korea and Far East Russia. An understanding of causes or issues in degraded forest ecosystems is essential to start structural/functional restoration activities. This special journal issue is a compilation of nine papers presented in a seminar on "Restoration Research of Degraded Forest Ecosystem" that was held at Seoul National University (SNU), Seoul, Korea during 13-14 April 200 by the auspices of Korea Science and Engineering Foundation (KOSEF), and by the support of Yuhan-Kimberly (Y-K), Korea Forest Research Institute (KFRI), Korean Forest Society (KFS) and Northeast Asian Forest Forum (NEAFF). It focused on their theme in a broad sense and encompassed practical rehabilitation, socio-economic and/or applied aspects and restoration strategies in Asia and Latin America.