A systematic system for control of PWD epidemics was not in
place in Korea until 2002 (Lee, D.L., in the Korea Forest Service, pers.
comm.). Therefore, data for districts that had PWD wilt pines prior
2001 were not used in the analysis. Data from eight districts neighboring
the heavily infested districts (e.g. Jinhae, Masan, Hadong,
Chilgok, et al.) were also excluded because PWD wilt pines (infected
by pine sawyers immigrating from neighboring districts) were very
likely present. Data for Pohang was not included because silvicultural
and conventional controls were applied simultaneously in
2004.